# Heat your water with a  heat pump - 50% electric savings!



## mikeathens

I know, my topic sounds like some cheezy scam ad in the back of better homes and gardens....

I lost my on-demand propane water heater when we had a bad downdraft during sub-zero weather last week.  It froze and then blew out the heat exchanger and left a nice pool of water in my house.  I went to Lowes and grabbed a 50-gallon electric tank instaed of pissing around with the on-demand - it solved my downdraft problem and gives me STEADY hot water vs. fluctuating hot/cold, which is not nice for showering.  I was shocked at the energyguide saying 4777 kWh/year avg. use.  That's about what my 4 kW solar array produces in a year.

I did some research and found this:  http://www.airgenerate.com/products/airtap.html

This thing mounts on top of your water tank and uses the refrigeration cycle to heat your water instead of resistance heating.  You plug it into a 110 v outlet and switch off the breaker for the in-tank heaters.  For us wood burners, this makes perfect sense!  If you are heating with gas/electric/etc., might not be such a great deal since you're robbing your air of some of its heat (that you already paid for once).  As a bonus, in the summer, it doubles as a small air conditioner/dehumidifier, so you're basically using the heat that your AC would normally throw outside to heat your water.

To save on electric, you all might want to look into this.  It costs $699 (I found a site with free shipping) and then there's a $300 tax credit for '09 taxes.  

No, I don't work for this place.  I just think it's a great idea.  I'm getting one, and planning to install a kill-a-watt meter on it to see what I'm actually using for hot water.  I'd be more than happy to share my results when it happens.


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## jdemaris

Mike from Athens said:
			
		

> I went to Lowes and grabbed a 50-gallon electric tank instaed of pissing around with the on-demand - it solved my downdraft problem and gives me STEADY hot water vs. fluctuating hot/cold, which is not nice for showering.  I was shocked at the energyguide saying 4777 kWh/year avg. use.  That's about what my 4 kW solar array produces in a year.



Sounds like you only make a litte more watt-hours per watt of solar panel than I do here in central New York.  I'm surprised considering I live in a pretty dark,snowy and rainly area.   I've got a 5250 watt solar array and made, on average, 458 KWH per month last year.  I.e., the 5250 watt array made 5500 KWH in a year. We use, on average, around 300 KWH per month - but we no longer use an electric hot water heater or clothes dryer.  My biggest winter power draw is the electric blower on my wood furnace that runs, just about, all winter.


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## mikeathens

jdemaris said:
			
		

> Mike from Athens said:
> 
> 
> 
> 
> I went to Lowes and grabbed a 50-gallon electric tank instaed of pissing around with the on-demand - it solved my downdraft problem and gives me STEADY hot water vs. fluctuating hot/cold, which is not nice for showering.  I was shocked at the energyguide saying 4777 kWh/year avg. use.  That's about what my 4 kW solar array produces in a year.
> 
> 
> 
> 
> Sounds like you only make a litte more watt-hours per watt of solar panel than I do here in central New York.  I'm surprised considering I live in a pretty dark,snowy and rainly area.   I've got a 5250 watt solar array and made, on average, 458 KWH per month last year.  I.e., the 5250 watt array made 5500 KWH in a year. We use, on average, around 300 KWH per month - but we no longer use an electric hot water heater or clothes dryer.  My biggest winter power draw is the electric blower on my wood furnace that runs, just about, all winter.
Click to expand...


The array was installed last April, so it hasn't QUITE been a year...but so far, if I remember correctly, the last reading I took (last saturday) was around 4500 kWh.  I suppose if it clears up and we have some really sunny skies in Feb and March, I could see another 1000 kWh on that.  GOOD sunny days will give us 20-22 kWh/day.

EDIT:  Oh, yeah, I forgot...we use about 600 kWh/month, of which a HUGE percentage is from running the aerator on our home sewage system, and the ultimate hog: our 1/3 hp myers jet (well) pump.  I always forget that most people don't have these two things, which is why they are at 300 or less kWh/month.


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## jdemaris

Mike from Athens said:
			
		

> The array was installed last April, so it hasn't QUITE been a year...but so far, if I remember correctly, the last reading I took (last saturday) was around 4500 kWh.  I suppose if it clears up and we have some really sunny skies in Feb and March, I could see another 1000 kWh on that.  GOOD sunny days will give us 20-22 kWh/day.
> 
> EDIT:  Oh, yeah, I forgot...we use about 600 kWh/month, of which a HUGE percentage is from running the aerator on our home sewage system, and the ultimate hog: our 1/3 hp myers jet (well) pump.  I always forget that most people don't have these two things, which is why they are at 300 or less kWh/month.



Well, no electric on our septic system at home, thank God. Just a gravity feed to a 1000 gallon tank and 300 gallon dry-well.  But, if I ever install a septic system on my property in the Adirondacks, an electric pump system might be required.  For now, we have a good old fashioned outhouse and an artesian well with a hand pump for water.

I had a 3/4 horse jet-pump here for years, hooked to a 200' well. That after using a piston pump for many years.  Jet pump is very inefficient. Water head is usually only 15 feet down - so even an in-house shallow jet bolted to the pump worked OK but wasted electricity.  Later, I installed a deep-well jet with two pipes -thus putting the jet down near the well bottom.   Worked better but still a power waster.  Finally installed a submersible 1/2  horse, 220 VAC pump.  The deep-well submersible pumps much more water and uses a lot less electricity.  It is much more efficient.

I'd still prefer to have gravity feed water to my home some day if I get around to it.  I've own several high-flow springs on the mountain top behind me.  But, building a reservoir and putting pipes five feet deep a 1/4 miles is a big project.  I have backhoes and dozers, but so far have never gotten around to it.

Our montly electric useage was 600-700 KWH per month before we trimmed down, when we were first thinking about installing solar.  Changed a bunch of appliances, CFL lights, removed the electric  clothes dryer and hot water heater, etc.  Got down to 280-300 KWH per month and then put in the solar.

Last year, we used more electric than we made in October, November, and February.   During some summer months, we made twice more than we used.  I keep close track since we are grid tie the power company pays us at the end of every calendar year.

My system is grid-tie and battery backup, which I had to design myself when we put it in.  Now, it's becoming more common and there are factory designed systems available.  I've got dual Outback inverters and dual Outback MX60 controllers/chargers along with a Rolls/Surette battery bank.   I'm glad I did it this way.  We've had two long power outages so far this year.  My power was never interupted.   A guy near me is on grid-tie solar and no battery bank.  When the power was out, so was his solar.


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## mikeathens

I looked at the nyletherm and it appears a bit more complicated to install, and uses the existing themostat...and remains connected to one of the elements.  It also runs on 220 vs. 110.  They're probably both about the same in performace, though.

The one i posted a link to runs at 690 Watts  (115v, 6A), and according to testimonials and mfg. data, runs 3-4 hours/day...that's a total of 2.8 kWh vs. (based on the data plate on the tank) 13 kWh/day!  I also figured that my on-demand propane tankless unit was consuming ~0.5 gallons of propane/day...or 14.7 kWh equivalents!  I guess what makes them attractive is the cost of operating:

Propane on-demand: 0.5 gallon @ $1.5/gallon = $0.75/day
Electric resistence: 13 kWh/day @ $0.10/kWh = $1.30/day
Electric heat pump:  2.8 kWh/day @ $0.10/kWh = $0.28/day  (Assuming 4 hr run time/day - I've seen estimates at closer to $0.50/day).

I'm planning to plug mine into a "kill-a-watt" meter, and see how it really measures up.


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## kimko

Geothermal companies tried to market demand hwgenerators but had so much trouble with them they stopped ,this is due to the high condensing temp for the task, I'm a refrigeration mech and it doesn't sound like a good idea to me. Never seen one so just an opinion .


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## mikeathens

kimko said:
			
		

> Geothermal companies tried to market demand hwgenerators but had so much trouble with them they stopped ,this is due to the high condensing temp for the task, I'm a refrigeration mech and it doesn't sound like a good idea to me. Never seen one so just an opinion .



My dad has a geothermal heat pump that is supposed to also produce DHW...he doesn't use it because the water is "tepid" at best.

I also have a friend at work who has one of the air-source water heaters, and he loves his.  He said it produces HOT water and is hassle free.  I would also assume that it has to be worth somethin gif it's enery star certified and eligable for a $300 tax credit:

http://aceee.org/consumerguide/waterheating.htm

http://www.energystar.gov/index.cfm?c=heat_pump.pr_heat_pump

I feel it's worth the "risk".


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## gpcollen1

I have the Nyletherm unit myself...

http://www.nyletherm.com/waterheating.htm

Hard for me to do any energy comparisons year over year or anything b/c I am continually changing things.  This unit is great in that I get my garage/cellar Air conditioned and dehumidified in the summer while it produces hot water.  As you said, it kicks on instead of the lower element on the hot water heater.  I am a do-it-yourselfer but regardless, this unit was easy to install into the HW heater - A wire or two, some pex and wallah!  The guys at nyletherm are pretty nice on the phone too!


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## velvetfoot

I didn't realize indirect hot water heating with oil cost so much.
These things are interesting as well for potentially doing double duty in the basement for dehumidifying.


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## Corey

Interesting idea.  I've seen them mentioned a few times before- but never heard any direct ratings of them.  It is a bit funny that you can go to walmart and buy a 7k btu window air conditioner for $175 bucks.  If they make that unit so it has a couple tubes that warm water, it's suddenly worth $700!

I believe there are also some HX units which fit on an actual residential AC condenser.  You basically pipe the compressed freon through the HX to heat your water and get rid of the relatively high grade heat - then through the air cooled coils to dump the rest.


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## Wet1

Other than the fact that our basement is typically in the low 40's in the winter (w/o the stove going), this sounds like it would be perfect for us.  We run a dehumidifier down there in the summer anyway, so this would certainly be a savings.

Here's a good overview on the systems:
http://www.toolbase.org/Technology-Inventory/Plumbing/heat-pump-water-heaters#initialcost


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## Wet1

CTwoodburner said:
			
		

> I have the Nyletherm unit myself...
> 
> http://www.nyletherm.com/waterheating.htm
> 
> Hard for me to do any energy comparisons year over year or anything b/c I am continually changing things.  This unit is great in that I get my garage/cellar Air conditioned and dehumidified in the summer while it produces hot water.  As you said, it kicks on instead of the lower element on the hot water heater.  I am a do-it-yourselfer but regardless, this unit was easy to install into the HW heater - A wire or two, some pex and wallah!  The guys at nyletherm are pretty nice on the phone too!


If you don't mind me asking, what was the cost of your system?


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## gpcollen1

I think I got mine for 600-700.  I think that is pretty good given that it seems like much more of a commercial product than a window a/c unit does for sure.


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## Wet1

CTwoodburner said:
			
		

> I think I got mine for 600-700.  I think that is pretty good given that it seems like much more of a commercial product than a window a/c unit does for sure.


Sounds reasonable to me.  Did you order directly from the manufacturer?  If not, who carries them?


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## Shipper50

I am very interested in any ones findings on the above posts. I have an 10 year old electric hot water heater and I think its the main cost of my bill every month as I don't use my electric furnace due to burning wood.

Thanks
Shipper


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## Wet1

I contacted Nyle about their Nyletherm 1 HPWH.  It would appear they are now out of stock of these units. In fact, they have licensed the design to another company, North Road Technologies.  They anticipate production in March... but you know how that goes.


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## Wet1

A question about the AirGenerate A7... what happens with the condensation that is developed form this heat pump?  I don't see a condensate pump mentioned anywhere.  What I did notice is they have drastically increased the price on the A7 from $499 to $699 in the last few months, ouch!  Supply and demand I guess...


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## mikeathens

Wet, from what I can see (I downloaded installation instructions), this is a gravity flow setup for the condensate.  It runs to the fron of the unit, and then down a tube.  Mine will go into the washer drain.  You can pick up a 110 v condensate pump at pretty much any hardware/plumbing store.

I did see a site that sells the air tap with free shipping.  Guess I had better get on the ball before everyone on here buys them out  hh:


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## Hansson

This is a cool one sold overe here.
You can add solar panels to it to.
http://www.norden.se/data/norden/files/image/norden_framsida_1.png

No info in English :-(


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## Wet1

Thanks Mike.  That's what I assumed as well, but I did see a review on Amazon where the reviewer mention having to insulate because of condensation issues, that's why I asked the question.


Hansson... 404 Not Found.


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## Hansson

Wet1 said:
			
		

> Hansson... 404 Not Found.



Sorry
Try this
http://translate.google.se/translat...denberedaren.se/&sl=sv&tl=en&history;_state0=


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## mikeathens

Hansson said:
			
		

> Wet1 said:
> 
> 
> 
> 
> Hansson... 404 Not Found.
> 
> 
> 
> 
> Sorry
> Try this
> http://translate.google.se/translat...denberedaren.se/&sl=sv&tl=en&history;_state0=
Click to expand...


Whoah!  F'n cool!  I guess I had better do a bit more searching and research to see which is the best one (efficiency-wise).  It seems, though, that you're looking at a year or so payback no matter which one you get.


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## gman1001

hey there - not to say things have not improved but here is my experience with NYLETHERM.

About 5 years ago, the State of CT offered the NYLETHERM  product for free to those who heated thier houses with electricity (me) and had an electric HWW.

A contractor came and installed the unit, it was pretty simple, and yes it replaced the lower heating element and has a neat backflush pipe system.

Basically the unit was crap.  It was not UL approved and continually ran and ran and ran.  Circuit boards melted continuasly and the poor guys from NYLETHERM and the HVAC contractor was at my house non-stop.

Someone else posted that NYLETHERM was looking to manufacture more units soon.  Thats exactly what they told me after my 10th unit melted down.  By then I'd had enough and ripped the system out.

I'f I had the time, and two less kids who demand alot of hot water, I'd try to work with/install a Solar Hot Water system instead, at least we know the sun doesnt need UL certification!  

I'm a believer in the Heat Pump Hot Water theory, thats why I jumped on board.  Maybe in the future this will become more reliable.

Food for thought...


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## mikeathens

Maybe that's nyletherm...I need to get the brand name from my coworker that he has.  Like I said previously, he has one that's been in service for 10+ years, and he swears by it.


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## gpcollen1

I can only speak to my experience as I did not have one single issue.  Maybe I will and maybe I wont - we will see.


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## Shipper50

Mike from Athens said:
			
		

> Maybe that's nyletherm...I need to get the brand name from my coworker that he has. Like I said previously, he has one that's been in service for 10+ years, and he swears by it.


Could you ask your coworker what kind of savings he saw with his? I didn't even know they made such a thing till I read this post.  

Shipper


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## Redox

Shipper50 said:
			
		

> Mike from Athens said:
> 
> 
> 
> 
> Maybe that's nyletherm...I need to get the brand name from my coworker that he has. Like I said previously, he has one that's been in service for 10+ years, and he swears by it.
> 
> 
> 
> Could you ask your coworker what kind of savings he saw with his? I didn't even know they made such a thing till I read this post.
> 
> Shipper
Click to expand...


Yeah, I'm curious too.  I venture to guess they are no longer in business.  I have been watching Nyle and other companies come and go for years.  It would seem to be a simple matter to add a heat exchanger to a cheap window AC unit, but the reality is much different.  A window shaker runs in a pretty consistent environment like 95 outside and 75 inside.  Put one in your 55 degree basement and it will turn into a snowball.  Increase the size of the evaporator and put a bigger fan on it and now it's too loud and drafty.  Then, there's water conditions.  Put a thin coating of scale on that heat exchanger and it kills the unit's efficiency.  These problems are just the tip of the iceberg (no pun intended).  The practical limit for a refrigeration compressor is about 110 to 120 degrees and this isn't hot enough for most people.  The compressor's discharge line can top out over 200 degrees (this is the "superheat" they are talking about), but the remainder of the condenser is going to be about 100 degrees.  GSHPs are ideal because they have a large compressor running a lot and it is possible to "steal" a little heat off the discharge without anyone noticing.

I really would like to see someone market a simple HPWH that worked for less than $1k.  They make a lot of sense, especially for those of us that live south of the Mason-Dixon line.  I have seen commercial varieties that put a large heat exchanger inside the tank, but they are rare due to their expense.  Restaurants would be ideal for this application, but I'm just not seeing it happening.

FWIW, I would be especially wary of ANY company that compares its product's consumption to a coffeemaker.  They pull 1 KW for about 5 minutes and then 100 watts or less for the warmer.  I think my Kill a Watt was claiming $15 a month for ours last time I checked.  Amish mantelpiece, anyone?   :roll: 

Hansson;  You keep teasing us with this European technology!  Know anyone in the import/export business?  We will just have to keep dreaming...

Chris


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## mikeathens

I asked my coworker about his again.  He said it's a "marvair" or "crispaire" (He can't remember).  His has been in service for at least 10 years.  He says his biggest complaint is the noise, which he compared to a furnace blower.  He hasn't done any exact measurements, but he said it definitely is a big savings.

I would guess that these things won't heat water up like your electric elements do.  I would also guess that you won't see as short of a recovery time, either.  I, however, have my water temp set at about 110 F right now, and I'll bet one of these will do the job just fine.  I'm willing to risk the $400 that it will cost.  I plan on putting mine on one of those kill-a-watt meters  out of curiosity.

(BTW, Redox.  I called at the right time, and I was lucky enough to get my Amish mantle.  It is beautiful, and only uses as much electricity as my 8-cup coffee maker.)


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## Redox

Marvair used to make a line of residential equipment, but now I see that they have concentrated on the modular office market and telecom biz (wall packs).  I don't see any HPWHs in their lineup, but I did find they have branched out into the marine business and have a 12VDC unit now; interesting.  Solar guys: http://www.marvair.com/12vdc.html

Like any heat pump, you have to lower your expectations a little bit.  If you want screaming hot water, these aren't going to do it for you, but would make an excellent preheat for a conventional DHW heater.  If you can get your 30-50 degree incoming water up to 90 degrees, that's a lot less conventional water heating you have to do.  I think a second water heater for storage would be a good idea.

Mike; the Airtap is up to $700 now that they are in production.  It's possible that early versions lacked certain features that would make them last.  I dunno.  That's still the best price I have seen for anything like it.  IIRC, other units I've seen in the past generally started over $1000.  Let us know how it works if you go this way.

Bet that Amish mantle is giving the 'ol Mansfield a run for its money!  You DID buy your limit of two of them, didn't you?  I was kidding; hope you were too...  (insert large smiley here).

Chris


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## mikeathens

Redox said:
			
		

> You DID buy your limit of two of them, didn't you?  I was kidding; hope you were too...  (insert large smiley here).
> 
> Chris



HUH???  I could a' got two of 'em??  Of course I was kidding...


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## mikeathens

ok...my coworker revised his story.  Apparently, he actually looked at the label this time.

He has an "E-tech WH-6BX-1".  He said this one isn't in production any more, he suspects because it uses R-22.  But, the company is still in operation, and still in the heat pump water heating business:

http://www.aers.com/etech.html


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## Redox

The E-tech has been around for years and from what I can tell is a good unit.  AERS probably has the largest installed base out there, but their primary business is commercial/industrial equipment.   I can't find any pricing online, but I recall seeing $1200 for one of these units and that was a while ago.  Most of their business was probably subsidized for government research installations, most of which show that (surprise), a heat pump saves energy over electric resistance!  The reason for the high cost and the lack of manufacturers is the limited demand, not unlike the GSHP business.  Now that energy costs are rising, there's a renewed interest, but we're really still in the '80s as far as the development goes.

Sometimes I appear to be overly negative here at times, but the HPWH can work if applied properly and be labeled a POS if not properly applied.  It is a completely different animal than an electric water heater and you may not realize you are going to have a problem until you get one installed in your basement.  I think if I lived in a colder climate, I'd let the manufacturers chew on these a while longer before springing for one.  Get a company like Trane or Carrier behind it and you will see some development.

BTW:  http://www.inhotwater.org/index.htm is a good source of info, but hasn't been updated since 2006 or so.  From my vantage point, not a lot has happened since then......

Chris


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## Wet1

Any update Mike?


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## mikeathens

No update yet, Wet.  I just paid off the credit card (I didn't want the compounded balance), and I'm planning to order one of these in the next week or so.  There's a prospect of a 6% pay cut + possible layoffs at my job, so I'm trying to be careful.  I can still justify this, though, because of the fast payback period - if it works.

One thing I'm concerned about is the lack of "real world" reviews on these...I'm leaning toward the AirTap A7, but I don't want to be a guinea pig.  I had, in fact, just called the company this morning, but tose lazy dogs in Texas weren't at work yet.  You know, everything should revolve around EST/EDT  (joke...just kidding).  If I'm going to shell out $700, I don't expect to receive crap.  I was going to see if they would provide me with some guarantee that I could return it after a month if it was garbage.  If the infomercials that I read are accurate, there was some subdivision in (I think) Tennessee where these were standard equipment in new homes.  There's one review on Amazon, but it sounds too much like a company rep planted it there.

Heating 100% with wood, this thing sounds really dreamy...I only wish they would explain the fact that you're robbing your house of heat that you already paid for once (if you heat with gas, electric, or pay for wood).

I will definitely report back when this happens...as well as any buying tips I can come up with .


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## Wet1

Thanks Mike.  I have a damp basement that requires me to run a dehumidifier for about 5 to 6 months out of the year.  I know there's some things I can and will do on the exterior of the house that will reduce this, but I know I'll still need some dehumidification even after these changes.  I've historically needed more hot water (on demand) than I think one of these HPWHs will provide, but between the indirect gas (for backup), me switching over to almost all (free) wood heat next year, and some DHW usage changes, I'm now thinking this HPWH might be the answer to my prayers.   Actual performance, reliability, and over-inflated product price still have me concerned.  I'm very much looking forward to hearing some real world results.


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## mikeathens

Well, even though I am still a bit unsure about this whole thing and hate being the experiment, I went ahead and placed an order for the Airtap.  I ordered from a dealer independent from the manufacturer, and heard nothing but praise from them.  $699 and free shipping.  Maybe I should look at it as "stimulating the economy"  :roll:  and this coming from a guy about to take it in the a$$ with a 5.4% pay cut.  Oh, well.  I guess better to have a job than be out begging for bread crumbs.  When I get it installed and run it for a week or so, I'll let y'all know if it's worthwhile.


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## Wet1

Mike from Athens said:
			
		

> Well, even though I am still a bit unsure about this whole thing and hate being the experiment, I went ahead and placed an order for the Airtap.  I ordered from a dealer independent from the manufacturer, and heard nothing but praise from them.  $699 and free shipping.  Maybe I should look at it as "stimulating the economy"  :roll:  and this coming from a guy about to take it in the a$$ with a 5.4% pay cut.  Oh, well.  I guess better to have a job than be out begging for bread crumbs.  When I get it installed and run it for a week or so, I'll let y'all know if it's worthwhile.



I'm very much looking forward to hearing about your results Mike.  Specifically, what your kill-a-watt meter reads comparing your electric DHW heater to this HPWH.  Also, please let us know what your ambient temps are where the HPWH will be located.  I'm not heating my basement right now and the temp down there is only about 47° (less than ideal for one of these), but that wont be an issue this summer or even next winter since I'm planning on heating with wood down there going forward.  My other concern is the actual recovery time for this system w/o using the other electric heating element in the tank.

If this doesn't turn out to be a 'FSM', I think I'll be ordering one as well.  Please keep us up to date as I'm be needing humidification in the not too distant future.


BTW, I hear you about the pay cut (I took one too), but it's better to take a cut than to be out on the streets.  I hate to spend money on something like this right now, but if it saves even more in the long run, it's money well spent IMO.


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## mikeathens

I'll definitely post updates...the usage meter really won't show a comparison between current usage and the airtap...for one, i've only had the tank in for a month or so, and second, it's hard-wired into the breaker box.

I am planning to place an intake vent in the wall right beside the wood stove (the HPWH will be just on the other side of the wall) and exhaust into the bathroom where the HPWH is located.  If the exhaust air is too cool for the bathroom, I'll probably place another vent to exhaust bleow the intake near the wood stove.

BTW, I happened to find another web site selling these for $599 w/free shipping (I paid $699 w/free shipping).  I'm going to see if the place will refund the difference (or at least 50% of the difference).  Hard times, man.  At least I can still afford to brew my own beer (the wife let me get a kegerator and 4 corni kegs before we heard the bad news about the pay cut!!).

Edit:  BTW, what's with the FSM comment?  If it wasn't for His noodly appendage, I wouldn't have found out about the HPWH  HAHAHA...


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## Wet1

If you wouldn't mind sharing the $599 source via PM, I would certainly appreciate it.

Regarding the FSM, it's pretty rare to find a FSM worshiper in your part of the country (I'm a big fan of him myself)... I use to live out that way, the 'influence', pressure, and never ending 'reference' (not to mention the time wasted doing so) drove me insane at times!  Long live the FSM and IPU!


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## CarbonNeutral

Definitely looking forward to updates - especially with your climate being similar to NE - easily 50 or lower in the basement in the winter - will this cause issues with efficiency/icing? I love their vent kit that I could use to pipe the cold air to the living area in the summer....


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## mikeathens

CarbonNeutral said:
			
		

> Definitely looking forward to updates - especially with your climate being similar to NE - easily 50 or lower in the basement in the winter - will this cause issues with efficiency/icing? I love their vent kit that I could use to pipe the cold air to the living area in the summer....



From what I know about heat pumps, even at 50, you're operating with a pretty high degree of efficiency.  FYI, their vent kit is $70.  There's no way I'm paying $70 for $7 worth of materials.  I plan on making my own.  Once it all up and running, I'll post some pictures, including whatever intake/exhaust contraptions I end up making.


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## Wet1

I believe these units work down to 32° F, but they are less efficient at these cooler temps.  Also keep in mind they will be blowing out even cooler air while operating.

Below is the efficiency chart provided for the Airtap A7:


----------



## CarbonNeutral

I'd also love to know where you saw it for $599.

Did you look at your state and federal rebates? If so, how much was on offer?

Nice clue about the vent kit... I don't have vents, but I would consider pushing a vent through the living room floor and putting a register fan in....


----------



## mikeathens

In the summer, the cooler the better, but I really don't want a freezing bathroom.  There's a chance that if I'm pulling 90 degree air from near the wood stove that the exhaust will actually be warmer in than ambient in the bathroom.  If that's that case, it will just exhaust there.


----------



## mikeathens

Well, the thing showed up today ($100 more than I could have gotten it for; my fault I guess).  Probably won't have any time to mess with it until saturday - of course, gotta split another cord of wood that day, too!!


----------



## Wet1

Completely unacceptable, it needs to be in operation TODAY


----------



## oldmilwaukee

I got real interested in one of these units last fall, but didn't pull the trigger once my geothermal installer told me about the desuperheater option for the GSHP I was ordering from him.  I'm anxious to hear how yours works for you.  Thanks for being the guinea pig!

One question I never got answered... is it possible for refrigerant to leak into the DHW if these units fail?  You would think that would make the FAQ list?


----------



## Redox

IIRC, it is a national code that the HX has to be a double wall vented design between potable water and refrigerant.  That way, if either the water side or the refrigerant side were to leak, it would leak to atmosphere and not cause contamination.  I haven't seen this "feature" mentioned much, but it is a good idea.

Let us know how it goes, Mike.  I wouldn't mind seeing a sample of temperatures on the air and water while it's running.  And don't beat yourself up over the $100; I couldn't find them any cheaper last month, and I know where to look.

Chris


----------



## xpertpc

They do not have a double walled heat exchanger, don't know of a national code but it is common sense and needed in most communities for antifreeze, and as far as a "freon" leak it would probably boil off -as far as I am concerned water from the hot tap is non-potable anyways. The output is distilled water at worst and am doing something similar myself.


----------



## CarbonNeutral

So I was browsing their site (airgenerate.com) and came across the forum they have. It wasn't well used, but It concerned me that there were people on there with issues that had not been addressed by representatives from the company. Why go to the effort of creating a forum, where most posts will be of technical/complaints, and not answer them? Then their contact form script wasn't working. 

I have emailed them with some concerns - we'll see if they get back. If they don't, it would really make me think twice about buying.


----------



## xpertpc

I have to amend my last post - they do in fact run the high (refrigerant) pressure line in your tank, dah don't know why I said otherwise. It is still an interesting concept. 2-5 year payback is not bad - then its free (if'n it don't break).


----------



## Wet1

Adding the tax credit, the payback appears to be even quicker.  I'm waiting to see what Mike's take is on this is before I put the trigger (thanks again Mike).


----------



## mikeathens

Well, I hope this works out, too.  Glad to see there are so many people interested - whether for energy conservation or simply curiosity.  If anyone wants any particular data (easy to get and low/no cost equipment), let me know here.  Since I'm heating with wood, there are some pretty wild ambient air temperature fulctuations (anywhere from 55 F to 80 F).  On top of that, I doubt that I will get the intake ductwork done right away (the plan is to take hot air from behind the wood stove).

I will most likely initially be able to give you a relative "chill factor" description where it will sit in the bathroom closet (it will be opened, of course).  Once I get the kill-a-watt meter, I'll be more likely to be able to provide more useful information - like water temperature setting, inlet/outlet temperature, kWh/day, possibly run time/day.  Let's keep our fingers crossed!


----------



## Shipper50

I too am waiting for a report. I have a basement that would be just right for this and use wood to keep the house somewhat warm. 63-68 depending on how high I keep the air adjusted.

My electric bill runs $100 or so with just 2 people that will soon be only one. Don't ask. I would like to cut it about 25% or more. I see my state of Indiana offers tax credit 2 times? 

Shipper


----------



## CarbonNeutral

CarbonNeutral said:
			
		

> So I was browsing their site (airgenerate.com) and came across the forum they have. It wasn't well used, but It concerned me that there were people on there with issues that had not been addressed by representatives from the company. Why go to the effort of creating a forum, where most posts will be of technical/complaints, and not answer them? Then their contact form script wasn't working.
> 
> I have emailed them with some concerns - we'll see if they get back. If they don't, it would really make me think twice about buying.



So they got back to me - here's their response:


> We appreciate your interest in our product, as well as your feedback.
> 
> 1. You are right that we should be monitoring and replying to posts in the
> forum. This is something that we will start working on during the next
> couple of weeks.
> 
> 2. For colder climates, we do have an enhanced AirTap model coming out
> soon with an auto-defrost feature and a high/low pressure sensor switch,
> which will help out with the unit's operation in colder climates. But if
> the AirTap is going to be in an environment where the ambient air
> temperature will be below 50'F for very long, most of our customers turn
> the AirTap off during those colder periods and use the original internal
> heating elements of their tanks.
> 
> 3. The AirTap is eligible for a federal tax rebate from 2009-2010 for 30%
> of cost, up to $1,500. More information on this rebate is available at
> (http://www.energystar.gov/index.cfm?c=products.pr_tax_credits).
> Information on state and local incentive programs is available at
> (http://dsireusa.org/).
> 
> 4. Thanks for bringing this information on the CGI script to our
> attention, and we will look into this immediately.
> 
> Thanks, and if you have any further questions, please feel free to give us
> a call or email here at the Support Center. We're here to answer those.
> 
> Jason Baker
> AirGenerate Support Center
> 713.574.6729 option 2
> support@airgenerate.com



Interesting and reassuring stuff.


----------



## mikeathens

I looked at the energystar site, and...whoopie.  Now my $300 tax credit is $209.70.  Still a good incentive, I guess.  I wonder if this "new" incentive is retroactive back to Jan. 1, or if the 30% thing starts on the day of the "stimulus". 

Hate to say it, guys/gals, but I think we are all royally screwed in this whole situation.  Assuming I make it through this thing and still have my house, the heat pumps/wood stoves/insulation/solar panels  and everything else dealing with energy efficiency and self reliance are going to be my source of security.  I guess that's why I'm investing in this sort of thing instead of the stock market.  I had my reservations 15 years ago when I bought into this whole "retirement strategy"; I would have been better off buying cases of Old Milwaukee and saving the money from recycling the cans!


----------



## Wet1

Mike,
Did you get it installed today?


----------



## mikeathens

I got the unit installed Saturday.  Not any fault of the airtap, but it was initially a nightmare to install.   You have to remove the hot water outlet nipple from the tank and replace it with one supplied with the unit.  My new whirlpool 50-gallon tank had one installed at the factory (only extended out of the tank 1 ½”), and I ended up crushing it with a pipe wrench trying to get it out.  I started thinking maybe it was tack welded or something, so I called the tech support – nope, threaded in there.  I used a pipe wrench and 3’ cheater bar, so it was insanely torqued in there.  I called lowes, explained the situation, and they said they’d take it back and give me a new one.  I had to go with a 40-gallon tank since all of the 50s had pre-installed nipples (keep this whole thing in mind if you are considering one of these).

So after all of this, the installation went smoothly.  I forgot to bring my data, but I took inlet temperature and then measured tank temperature about every half hour.  The inlet was about 49 F, from what I remember.  The air tap brought it up to 115 in about 3.5 hours.

It runs (so far) about 3 to 4 hours/day (say two hours of run time every 12 hours).  I originally set the temp at 115 F, and when my daughter took a bath the first night, the water was only tepid.  I called the tech support and was told that there is a 15 degree F temperature differential between on and off.  So, I am assuming the temperature was about 100 F when my daughter took her bath, which would explain this.  I have since cranked up the temperature to 125 F, so we’ll see if this solves the problem.

Other observations:

*1.*  The manual has some text about replacing the cold water inlet with the anode rod, and putting the cold water inlet in the anode rod port.  This was really unclear, and after messing with it for a while, my senses took hold and I realized there was absolutely no reason for this.  When I asked tech support about this, they said sometimes the rod is in the hot water port, and interferes with installation.  Something to keep in mind if you get one of these.  I suggested they make this a bit more clear in the manual.
*2.*  The manual states that you should replace the anode rod twice a year.  I told them this was a pretty big operating cost, and maybe this should be stated up front.  They told me this was a typo, and it should actually say “replaced every two years”.  Much more acceptable.
*3.*  Recovery rate is not nearly as fast as using the elements.  Something to keep in mind.
*4.*  You’re not supposed to keep the elements powered up, something about damaging the airtap.  However, if there’s a high-demand period, they said you and unplug the airtap, and power up the elements, just not both at the same time.
*5.*  I have a thermometer in the room with the airtap.  When running, it does produce a pretty cold breeze, but it really doesn’t make much of a difference in ambient air temperature (which is about 68 F, by the way).
*6. * The unit is not set up to allow ducting of supply air.  You can vent the exhaust, though.  The exhaust vent is not a size to allow installation of a standard sized diffuser, so I’m going to have to fabricate something myself (since there’s no way I’m going to pay $78 for a $2 piece of plastic.
*7.* If you are bothered by noise, this might not be for you.  It’s about as loud as a dehumidifier.
*8. * If you are looking at this to run double-duty as a dehumidifier, keep in mind that it doesn’t run based on ambient humidity.  It’s a water heater.  You will get supplemental dehumidification/air conditioning when it runs, though.

So far, I’m happy with it.  I am actually amazed that this thing can heat the water so high.  We’ll have to see how durable it is in the long run.


----------



## Wet1

Good info Mike.  Did you hookup your kill-a-watt meter to it yet?

So it sounds like this might be marginal (at best) for a family of three who all shower in the evening, is this a safe assumption?  Add in a load of laundry or run the dish washer and I question if it would keep up.  I know they are releasing a larger version soon (12k I believe???), although the price and performance are still unknown.  

I'm beginning to think the best way to run one of these things (for me anyway) might be as a preheater for a second DHW tank. This way the AirTap would be doing the bulk of the heating, but the second tank down stream could heat any additional water as demand called for it.   Example, have the cold water feeding into the AirTap equipped tank with a set point of say 125°+ F., then have it feeding into a second (smaller) DHW tank with a set point of say 115° F.  Since the incoming delta into the second tank would be small, I cant imagine it would cost much in additional energy to use such a system and it would certainly have a high capacity if demand actually called for it.   One down side to doing this is that you would have additional tank losses.

The other option might be to plumb it into a larger volume tank so there's enough warm water for at least two or three showers.  Even though the recovery would take a long time, higher demand would likely be met.  But again, there's the additional tank loss with the large volume of warm water.

At least with both of these scenarios people wouldn't end up with cold showers and the bulk of the water heating could still be done using this efficient device.

With this said, I have a 50 gal. (maybe it's a 53 gal.) electric water heater and a 80 gal. SuperStor hooked to my gas boiler (indirect) configured with a valve that allows me to use whichever I chose.  I also have another 40 gal indirect tank kicking around.  Both the 40 and 80 gal indirect tanks are not configured like a std. electric DHW heater in their layout.  I think both have the water inlet at the bottom and the outlet at the top.  Could the Airtap be hooked up to one of these tanks (I don't know how the system is plumbed into a traditional electric DHW tank)?  If so, what I'm thinking is I installing the 40 indirect tank on the gas boiler and installing an AirTap unit on the 80 gal indirect tank.  If the AirTap on the 80 gal tank did not meet our demand needs, it could be hooked up to feed into either the 50 gal. electric tank or into the 40 gal indirect gas fired tank.  Thoughts?

My other concern is dehumidification.  I need to run a dehumidifier in the basement during the warmer months.  Any feel for how much dehumidification you're getting out of this unit?  I assume the condensate is dumped through a drain, correct?  Do you think this unit would cover my needs if I was only collecting a couple of gallons a day through a traditional dehumidifier in the summer?

Thanks again for your work on this project Mike...


----------



## mikeathens

Wet1 said:
			
		

> Good info Mike.  Did you hookup your kill-a-watt meter to it yet?
> 
> So it sounds like this might be marginal (at best) for a family of three who all shower in the evening, is this a safe assumption?  Add in a load of laundry or run the dish washer and I question if it would keep up.  I know they are releasing a larger version soon (12k I believe???), although the price and performance are still unknown.
> 
> I'm beginning to think the best way to run one of these things (for me anyway) might be as a preheater for a second DHW tank. This way the AirTap would be doing the bulk of the heating, but the second tank down stream could heat any additional water as demand called for it.   Example, have the cold water feeding into the AirTap equipped tank with a set point of say 125°+ F., then have it feeding into a second (smaller) DHW tank with a set point of say 115° F.  Since the incoming delta into the second tank would be small, I cant imagine it would cost much in additional energy to use such a system and it would certainly have a high capacity if demand actually called for it.   One down side to doing this is that you would have additional tank losses.




Don't have the kill-a-watt yet.  Marginal?  Not sure.  I've only had it in service for a few days, and so far I'm pleased with it.
Here are my thoughts on the preheater idea:  If you were to do this, what purpose would the second tank serve?  You are still using resistence heating to keep that water hot during periods of non-use.  During periods of heavy use, you'll just be pulling cold/cooler water straight through, and the elements aren't going to be able to keep up any better.  Are you just running regular electric heater right now? 




			
				Wet1 said:
			
		

> The other option might be to plumb it into a larger volume tank so there's enough warm water for at least two or three showers.  Even though the recovery would take a long time, higher demand would likely be met.  But again, there's the additional tank loss with the large volume of warm water.
> 
> At least with both of these scenarios people wouldn't end up with cold showers and the bulk of the water heating could still be done using this efficient device.
> 
> With this said, I have a 50 gal. (maybe it's a 53 gal.) electric water heater and a 80 gal. SuperStor hooked to my gas boiler (indirect) configured with a valve that allows me to use whichever I chose.  I also have another 40 gal indirect tank kicking around.  Both the 40 and 80 gal indirect tanks are not configured like a std. electric DHW heater in their layout.  I think both have the water inlet at the bottom and the outlet at the top.  Could the Airtap be hooked up to one of these tanks (I don't know how the system is plumbed into a traditional electric DHW tank)?  If so, what I'm thinking is I installing the 40 indirect tank on the gas boiler and installing an AirTap unit on the 80 gal indirect tank.  If the AirTap on the 80 gal tank did not meet our demand needs, it could be hooked up to feed into either the 50 gal. electric tank or into the 40 gal indirect gas fired tank.  Thoughts?
> 
> My other concern is dehumidification.  I need to run a dehumidifier in the basement during the warmer months.  Any feel for how much dehumidification you're getting out of this unit?  I assume the condensate is dumped through a drain, correct?  Do you think this unit would cover my needs if I was only collecting a couple of gallons a day through a traditional dehumidifier in the summer?



I think the larger tank options would be best.  I'm thinking now maybe I should have gone with an 80-gallon tank, for the same reason as you:  more storage.  As far as the inlet being at the bottom, the thing mounts to the cold water inlet/hot outlet nipples to keep it in place, with adjustable rubber feet in the front for leveling.  I'm sure you could rig something up to mount it to, though.  It would still be attached to the hot side.  You are actually replacing the 3/4" hot nipple with a new one included in the kit.  The airtap heat exchanger is then fed into the hot port (it's a copper "coil" about 6' to 8' long).  The thermostat bulb goes in there two.  The hot water then exits out the back of this fitting through a tee.



			
				Wet1 said:
			
		

> My other concern is dehumidification.  I need to run a dehumidifier in the basement during the warmer months.  Any feel for how much dehumidification you're getting out of this unit?  I assume the condensate is dumped through a drain, correct?  Do you think this unit would cover my needs if I was only collecting a couple of gallons a day through a traditional dehumidifier in the summer?



I can't really say how much dehumidification you'll get, but if you're running your dehumidifier for two, two-hour periods each day, then this might do the trick.  I would classify it as "supplemental", though.  You'd probably see your full-time dehumidifier run less?  Condensate flows by gravity through a tube to drain/sink/whatever.

I can't really say how this will work out in the long run as far as meeting our demands, but I'm convinced that it is going to save bucu bucks, so I'm determined to make it work.  I feel that I might see the 40-gallon tank working fine simply by keeping the thermostat set to the higher temperature?


----------



## mikeathens

One more note:  I wrote the company about the change in tax credits - they said if you buy a new tank or other equipment, that also counts toward the 30% tax credit, since the air tap is just one component of the hot water system.  That will put me at about $300 back now.


----------



## mikeathens

In case anyone is still interested in this...

It's been a week since I installed the AirTap (still no kill-a-watt meter).  I have turned the temperature setting up to its max (130 F).  Here's the only drawback I have encountered so far.

Since the thermostat operates on a 15 degree temp differential, it is possible to not use any hot water all day and still get hot (but not 130 degree hot) water out of your tank.  In other words, let's say the heat pump runs at 5 am, and is then off all day.  I might come home at 6 PM to take a shower.  Just as I step into the bathroom, the heatpump kicks on again, even though I have not started the hot water.  This means that the water temperature has fallen throughout the day, and is now at approximately 115 F.  My shower is still hot, just not as hot as it would have been with the elements keeping the temperature constant all day.

My recommendation with this thing is go with a larger tank (80-gallon) and store more hot water.  I'll make due, I'm sure, but the 40-gallon tank I got will probably leave me in situations with cold water at some point.

I also was thinking that maybe placing an uninsulated tank just before the heat pump might provide some "preheating" using ambient air.  If I have 48 F water coming into an uninsulated tank and I don't use a lot of water, it is possible that that tank could warm to close to the ambient temp. of 70 F prior to being heated to 130 F by the heat pump.  Just a thought...


----------



## karri0n

130 isn't really hot enough for us. Our oil boiler is set to 160, and even then we generally do showers with the tap on full hot. No tank or storage to speak of. I haven't read anything but page 5, so hopefully this wasn't addressed earlier.


edit: went back and read. I do like the sounds of this thing, but it seems like their marketing dept needs to do a bit of work on their website and documentation. I don't use electric hot water or even have a separate water heater from my furnace, but it seems pretty useful to those who do. Thanks for the detailed posts Mike.


----------



## CarbonNeutral

karri0n said:
			
		

> 130 isn't really hot enough for us. Our oil boiler is set to 160, and even then we generally do showers with the tap on full hot. No tank or storage to speak of. I haven't read anything but page 5, so hopefully this wasn't addressed earlier.



160 will scald within seconds, so either:

your water has cooled a lot by the time it gets to the tap - possible but not likely

you are reading the temperature inside the boiler heat exchanger - this is effectively the temperature of the water that gets circulated around your forced hot water system. Your hot water supply gets heated to this temperature, then is mixed with cold  using a thermostatic valve, usually on the side of the boiler to a safe temperature.

your thermometer is busted


I am going to bet that the second is the case - you may want to turn up the temperature on this valve, and measure the temperature coming out at the faucet - I bet you it's not 160....


----------



## mikeathens

karri0n said:
			
		

> 130 isn't really hot enough for us. Our oil boiler is set to 160, and even then we generally do showers with the tap on full hot. No tank or storage to speak of. I haven't read anything but page 5, so hopefully this wasn't addressed earlier.



I agree, 160 is scary hot.  130 is actually too hot, but I am banking on showering in the lower-range 115 (which is perfect).

160 will peel your skin off and then cook your muscles to the bone.  Take some carrots, celery, onions and cabbage in there with you, too to make it a meal.

I would measure the temp at the tap to get a true temperature.  If you have the hot tap full open without mixing any cold, I'll bet you're actually looking at 115 to 120.


----------



## Wet1

Thank you for the update Mike.  Very much looking forward to your Kill-a-watt readings when you get them.  You might want to consider putting the Airtap on a timer and having it shut off from say 8PM until say 3 PM, this way it doesn't have a chance to completely reheat your tank after taking your evening shower (although still brings it up a bit should you need warm water), and then kicks on again before you come home to get your tank fully up to temp.  You would save energy doing this as well since your tank losses during the night and most of the day would be less because the delta isn't as high.  Obviously you would have to play around with the timing to work with your family's schedule, but it should solve your 115° water temp issues, plus save you some money in the long run.



			
				Mike from Athens said:
			
		

> Here are my thoughts on the preheater idea:  If you were to do this, what purpose would the second tank serve?  You are still using resistence heating to keep that water hot during periods of non-use.  During periods of heavy use, you'll just be pulling cold/cooler water straight through, and the elements aren't going to be able to keep up any better.  Are you just running regular electric heater right now?



Using two tanks would reduce the recovery time and increase the supply for more hot water on demand.  Since the first tank (AirTap tank) would be feeding the second tank with hot water (until it's supply is slowly diminished), the second tank would not have to work nearly as hard to bring the water up to temp (if at all) and the recovery would be minimal unless you used a lot of hot water.  In the rare event you started to deplete both tanks (very unlikely), the two would also recover much faster.  Yes, you'd loose a little efficiency since you'd still be using a resistance heater in the chain and it would have to maintain the second tank temp due to tank loss (which isn't that great), but the delta would almost always be minimal, so it wouldn't be carrying much of the work load at all.  Better yet, you could use two tanks, each equipped with an AirTap, but set the first at a lower temp (say 75°) to reduce tank losses, this would be more costly to initially set up, but it would be very cheap to use and would supply a lot of hot water with less tank losses.

I have both resistance and gas DHW systems in place, I'm choosing to use the electric tank now because I have some issues with my gas provider... I would prefer not to give them my money, even though it would be cheaper for me to heat the water with gas.



> I think the larger tank options would be best.  I'm thinking now maybe I should have gone with an 80-gallon tank, for the same reason as you:  more storage.  As far as the inlet being at the bottom, the thing mounts to the cold water inlet/hot outlet nipples to keep it in place, with adjustable rubber feet in the front for leveling.  I'm sure you could rig something up to mount it to, though.  It would still be attached to the hot side.  You are actually replacing the 3/4" hot nipple with a new one included in the kit.  The airtap heat exchanger is then fed into the hot port (it's a copper "coil" about 6' to 8' long).  The thermostat bulb goes in there two.  The hot water then exits out the back of this fitting through a tee.


I like the idea of having a large storage tank, but the only real down side is the increased tank loss... which is why ideally two smaller tanks with staggered temps, both equipped with AirTaps, would be more ideal.

I don't know how well your preheating tank would work without some type of HX in/on it.  It would take a long time for 40 something degree water to come up to ambient temp without some type of HX or heat sinks on the tank.  Now if you could place it close to your wood stove, that might work well.


Please continue to keep us updated with your findings!


BTW, I have to agree with the guys KarriOn, it's very doubtful your DHW temp is 160°, that would cause instant burns.  140° is about the limit, and even that can burn you if you stay under the water for any period of time.


----------



## mikeathens

Wet1 said:
			
		

> I like the idea of having a large storage tank, but the only real down side is the increased tank loss... which is why ideally two smaller tanks with staggered temps, both equipped with AirTaps, would be more ideal.



Haven't gotten to it yet, but I am going to wrap my 40-gallon tank with R-13 fiberglass insulation, and top that off with some "double bubble" foil insulation (I have lots of both insulation left over from working on the house).  The only part of the tank that won't be covered is the bottom.  That should help tremendouly with tank losses - this would apply to a larger tank, too.  It's going to look like a component of the space shuttle when I'm done, but it should do the trick.


----------



## karri0n

Thanks for the clarification. The 160 is on the adjuster for the HX, and I don't actually have a thermo that reads what the temp is. This temp very well may be only used for the radiators, and the DHW gets cooled thermostatically like you say. I do realize there's no way the water coming out of the tap is at 160.


----------



## semipro

Mike from Athens said:
			
		

> In case anyone is still interested in this...
> 
> It's been a week since I installed the AirTap (still no kill-a-watt meter).  I have turned the temperature setting up to its max (130 F).  Here's the only drawback I have encountered so far...



I'm interested.  I've been lurking until I actually had something to say.  

I have a GSHP, woodstove in the basement, electrical resistance water heater in the basement, and need dehumidification in the summer and am dedicated to reducing our off-the-grid energy demands so this is all very interesting to me. 

I guess a few questions/thoughts I have: 

After reading the whole thread and from what I'd already planned I'm now considering going with solar preheat, AirTap primary heat, with a tankless unit after that for higher than normal loads and to avoid tepid water.  I would probably also control time-enabling of the various components with my home automation system (x10).  I'd rather not use the tankless unit, instead using the remaining resistance element in the tank the AirTap is installed in.  I'd like to know more about why AirTap recommends against this.  Its hard to imaging how an element separated from their high-side condenser line by a foot of water in the tank would cause problems.  

I realize that this scenario is not ideal for dehumidification but that's not my primary goal.  I'd take what I could get as far as dehumidification and use my current dehumidifier or GSHP to make up the difference. 

Thanks Mike for keeping us posted, even the lurkers   I really hope this works out well for you.

Oh, yeah, I'm also a fan of the FSM but never made the connection with your avatar.


----------



## tom in maine

I've installed both the Airgenerate unit and the Nyletherm.
Both have their pluses. 
The Nyletherm is much more rugged, built in this country and will be re-usable if your tank fails, since it circulates water into the storage tank.
It requires 220VAC and is hard wired. Since we manufacture unpressurized tanks, we will hook it up to a larger solar tank.
I ran it with an 80 gallon tank and never ran out of hot water. That was with two people in the house. I suspect it might not keep up with a couple teenagers.

The Airgenerate is cheaper and is not as rugged. It is 110VAC and plugs in. The heat output is the same. Since it has a heat exchanger that has to be installed in the
tank, I suspect that is will be difficult to move to another tank. The heat exchanger seems fragile to me, although it went in the tank okay.
It is less expensive, but you get less for the money.

Both units have a COP of about 2. I usually run the Nyle in the summer only, since my basement is insulated with spray foam and it chills the floor too much.
The Airgenerate ran into January and frosted up. We shut it down and should turn it back on again. 
Of course, this is Maine and both basements are quite small.
The Nyle lists for $1,000 and the Airgenerate is about $600. The Nyle unit is sometimes on sale or available as a refurb. (They had some control changes.)

BTW, most boilers have a mixing valve that would (usually) never allow you to run water over 120F out of the tap. Anything 130 or higher is going to be intolerable and dangerous.


----------



## Wet1

CZARCAR said:
			
		

> prof is currently using a nyletherm to heat DHW + built a refrigerated box for cold exhaust....still a dehumidifier of course.


Who???


----------



## Wet1

Wet1 said:
			
		

> I contacted Nyle about their Nyletherm 1 HPWH.  It would appear they are now out of stock of these units. In fact, they have licensed the design to another company, North Road Technologies.  They anticipate production in March... but you know how that goes.



As an update to this, I heard from Rob at NRT about their HPWH.  Here is the response I received and there are more details on their website...



> Hello,
> Thank you for your interest in the GEYSER Heat Pump Water Heater, now available from North Road Technologies. Energy savings have never been more important, and interest in the GEYSER has been overwhelming! Because you have expressed an interest in learning more about the benefits of utilizing the GEYSER, we are pleased to give you the opportunity to review our exciting innovation. We have enclosed our brochure and our web site is now available, at www.northrdt.com - please check us out!
> 
> The GEYSER is the successor to the Nyletherm and Hot-Shot units from Nyle Corp, which have had a successful following in the marketplace since 2000. North Road Technologies has invested heavily in product development to improve the efficiency, reliability, and user friendliness of these units, and we are now ready to re-introduce this improved and advanced product. Based on our production schedules and the strong customer demand in our products, we are now accepting orders for delivery from approximately May 20, 2009, so act quickly and reserve your unit now. Please feel free to respond directly to this email, or respond to the inquiry form from the web site. Either way, you will be able to start saving money while protecting the environment in just a few short weeks.
> 
> Thank you again for your interest, and we look forward to hearing from you.
> 
> Best Regards,
> 
> Rob MontenegroNorth Road Technologies(203) 988-9338 (Mobile)robmontenegro@northrdt.comwww.northrdt.com


----------



## newstove

So, I was checking these out, and trying to determine if it would/could be useful to me or not.

Right now, I have an oil fired boiler that provides hot water via an indirect hot water tank (3 zones - 2 are heat exchangers for our air handlers for heat, the 3rd is the indirect hot water tank.)  Once nice thing about the tank is that it is an extremely well-insulated Mega-Stor tank, and has great efficiency for these types of tanks.

Looking at the setup of the current tank, it has a cold water inlet at the bottom, a hot water outlet at the top, and the boiler in/out on the side for the indirect coil.  I.E. it's not gonna be easy to hook one of these units up (I was checking out the Geyser unit, and even exchanged a few e-mails with them today.)

We currently have a 50 gallon tank and 2 teenagers.  'nuff said there about what happens with the hot water.  ;-)  We also have an 80 gallon jacuzzi tub which, of course, we can't fill without fully draining the tank.  Based on this and other things, it's clear the builder of the house wasn't thinking clearly.

Anyway, what I was thinking, is that I could possibly kill 2 birds with 1 stone here.

(1) Install second hot water tank (30-40 gallon.)  Make this one electric, and install it before the existing indirect hot water tank, so that the outlet from the new tank goes to the inlet of the existing tank.
(2) Install the heat pump on the electric tank.

In theory, this should give us two benefits - a larger reservoir of hot water, and most of that hot water will be heated by the heat pump.  The oil burner should only run to provide hot water when the heat of the indirect tank drops below temp, either due to being exhausted, or because the tank has been idle enough that it cooled down.

There is also a third benefit - I usually have to run a dehumidifier in the basement most of the time during the spring/summer/fall.  This hot water heat pump also acts as a dehumidifier.  So, in actuality, I wind up killing 3 birds with 1 stone.

I know these heat pumps are quite expensive - the Geyser is $1,199!  Plus a new tank, plumbing, wiring, I'm looking at ~2K or so when all is said and done.  But, I'll be burning a lot less oil (but probably have a higher electric bill - we'll have to see what the offset is.)

So, opinions?


----------



## DBoon

My first take is that it will really depend on your electric rates and how bad the humidity is in your basement in the summer. 

With oil at $4/gallon the previous winter, I did a back of the envelope calculation that showed that electric water heat at ~12 cents a kilowatt hour was competitive with oil.  I heat my water with off-peak electricity at ~10 cents/kWh, and I was curious.  

Here is the math:
3414 BTUs/kWh
140,000 BTUs/gallon of oil

Electric water heat = (3414 BTUs/kWh)/($0.10/kWh) = 34,140 BTUs/dollar (assuming 100% efficiency and ignoring tank losses)
Oil Heat = [(140,000 BTUs/gallon)/($4/gallon)]*65% efficiency = ~22,500 BTUs/dollar

So with oil at $3/gallon, it's probably the same.  At $2/gallon, oil is cheaper. 

BUT, with the heat pump water heater, the coefficient of performance is ~2, so the cost per BTU is halved, or the BTUs/$ = 68,000.  Thus, it is competitive with oil at $1.50/gal.  We probably won't see that for a while.  

Whether it makes sense economically is dependent on how much water you use in a year.   Before I invested in this, I would make sure that there were water saving fixtures on the showers.  A front loader washer may be a good investment also, depending on how many loads of warm or hot laundry you do in a week.  

One thing I haven't taken into consideration is the fact that oil burners are usually a lot more inefficient in making hot water during the summer when they are not also used for heating.  This tilts it further to a replacement with the heat pump.   Also, the dehumidification is a nice side benefit, and another money saver if you run a dehumidifier in the basement anyways.  

If you were to do it, I would go with an 80 gallon electric tank as a pre-heater, and maybe even get ride of the oil tank completely.  

I read a great article about someone who put a 20 gallon hot water tank feeding the bathroom that his teenagers used so that there was essentially a hard stop to the amount of water they would use.  I would definitely do that if I had teenagers.  I don't recall going through a tank of hot water when I showered as a kid.


----------



## newstove

Thanks for the reply.

Right now, in my area, it's ~$0.18/kWh for electricity (no such thing as "off-peak" on my bill ;-( ) and oil is $2.29/gallon.

We already have the front loader washing machine, shower saving devices in the showers, etc.

It's not a huge issue - one of the biggest complaints is that two people cannot take a shower at the same time without one of them running out of hot water (kids upstairs, us downstairs.)

Also, our boiler is listed as 86.2% efficient.

So, it is sounding like, economically, we are better off with the oil boiler right now.

The one thing that comes into play is the dehumidifier.  We must run it a whole lot, so that is like wasted hot water we could, in theory, be getting back...

But, on the flip side, I would like to reduce my reliance on heating oil, and do my part for the environment - the more green electricity I can use instead of oil, the better I feel.

I was looking at the wood boilers, but those are outrageously priced, and you still have to feed 'em wood which costs.  They are nowhere near economical, at least not right now.  Maybe if oil hits $10/gallon, but if that happens, I expect wood prices to skyrocket as well.


----------



## DBoon

Just keep in mind that the boiler AFUE efficiency rating isn't what you are really getting in the real world - it is essentially what the efficiency of the fuel conversion is before heat transfer and system losses.  The heating of the hot water is probably not occurring at 86% efficiency. 

At 18 cents per kWh, it's hard to see how you could save money with a heat pump hot water heater, even with the savings on running the dehumidifier.


----------



## mikeathens

Keep in mind before you invest in one of these HPWHs:

1.  They do work, and they do save a lot of electricity.
2.  The heating elements can heat up 50 gallons of water to 120 F in about an hour.  The HPWH will take two to three hours to do the same thing (depending on ambient air temp).
3.  The HPWH doens't keep your water at a constant setting like the electric elements.  Instead, you have a 15 F drop before it kicks on.

So, keeping in mind #3 above, consider this scenario (I went through this before in this thread, but I think it's important enough to reiterate).

HPWH runs and shuts down.  You now have 130 F water in the tank.  Run a load of laundry.  Run a load of dishes.  Kids take a bath that evening.

Now, you get up in the morning to take a shower.  The water is running for about 30 seconds, and the HPWH kicks on (this is the first time since the bath, dishes, and laundry).  After about 3 minutes in the shower, the water is still warm (comfortable, but not super hot).  You have about 2 more minutes to finish up.  After that, it will be somewhat cool.

Now, you really don't have hot water for about another hour or two.

Some may look at this as a big inconvenience, which I suppose it could be.  My family just has to adjust schedules.  Kids bath at night, wife showers at night.  I take mine in the morning.  We have a Bosch front load washer, GE dishwasher, both can heat it's own water if inlet temp is too low, so we run these at any time.  I think it's a small price to pay for huge energy savings.

EDIT:  one last point about the cost.  If you have to buy the HPWH AND a tank, both are components of the HPWH system, and both are eligible for the 30% tax credit.  IF you pay $1200 for the HPWH and $700 for the new tank, you can claim a $570 tax credit on your '09 taxes.  That's a good chunk of change.


----------



## Wet1

Newstove, you should probably do just as you initially mentioned, add a 40 gal electric tank (with the Airtap A7 installed on it) inline before your indirect oil fired tank.  I should also mention you can get used 40/50 gallon tanks on CL for next to nothing since most people don't want them.  I picked up my 50 gal tank for $25 and it was only three years old... just something to consider.




I've been mulling this over for several months now and I still haven't made any concrete decisions yet, but since humidity in our basement will be an issue soon, I need to start thinking harder about this.  As I stated earlier, I have a NG fired indirect system and a separate electrical resistance DHW system.  After spending thousands to convert from oil over to NG, I've not used the system at all as I've been burning wood/pellets and I don't see it being used in the foreseeable future.  Since the NG system is not being used, it obviously makes it much less efficient to use NG to heat the DHW.   

My biggest fear with switching over to the HPWH is that it will not meet our normal demands, and based on Mike's gracious input, it sounds like this fear is justified.  I know a 12k BTU unit is going to be released soon, but it will be more costly, and I'm still not sure this will cover our needs w/o any issues.  Regarding the manufacturers, I suspect the NRT/Nyle unit is superior, but at twice the cost, I don't see how I can justify it.

Since I want high capacity, low operating cost, and some of the dehumidification benefits of the HPWH, I'm strongly considering building a hybrid solar and HPWH system.  What I'm thinking is making a solar DHW system similar to the one Gary built (http://www.builditsolar.com/Experimental/PEXColDHW/Overview.htm), but with slightly larger capacity and make it out of copper rather than PEX.  Based on his numbers and my upgrades to his design, I suspect this system would cover at least 95% of our DHW needs.  I would feed the large solar storage tank into my existing 50 gallon tank, which I would install the Airtap A7 on.  The Airtap would hardly ever have much of a load on it, but it would do the job to maintain tank temp form tank losses, and work as a backup in the event the solar system wasn't keeping up with our demands (although this would probably be fairly unlikely).  It looks like I could build the DIY solar system for around $1200 (with the more recent decrease in copper prices and adding in my upgrades), plus another $400 for the Airtap A7 ($600 shipped, minus the 30% tax credit).   $1600 is a fairly large amount to spend on a DHW system, but assuming I spend $600 a year now to heat water and still have some issues with running out of hot water, this makes the payback period under 3 years... which isn't that bad IMO for a DHW system with nearly limitless capacity.  

Then again, with a solar system covering 95% of our hot water needs, I wonder if it would even be worth adding the HPWH at all and just keep the existing (and reliable) electric DHW tank as it sits.  I guess the biggest reason I'm really leaning toward adding the HPWH is because I don't know that I'll have time to build the solar system this summer and I'll need the dehumidification soon... plus I don't think we'll have much of a demand for DHW until fall.  Decisions, decisions...


----------



## newstove

Yeah, that's what I'm leaning towards.  Of course, my wife thinks I'm nuts. ;-)

I just feel better conserving energy if I can.  Kinda like the free wood argument - yes, it's work, but otherwise most of it will rot, so why not take it, stack it and burn it.  Gives me free exercise...

Robert at North Road Technology (http://www.northrdt.com/index.html) has been great - has answered every question and even sent me the installation manual so that I can review how the install would go.

As far as I can tell from specs and such, the Geyser heat pump will consume about the same amount of power as my current dehumidifier, and should have a better efficiency.  So, I think that might wind up being a wash during the seasons when I run the dehumidifier.  Now I just have to wrap my mind around the cost of the unit!

Thanks for all the feedback.


----------



## DBoon

It's not always about economics - do what feels right to you if you have the spare cash and can afford it.   There is a lot to be said for doing what you can to reduce oil usage.   

Let us know how it turns out.


----------



## newstove

DBoon said:
			
		

> It's not always about economics - do what feels right to you if you have the spare cash and can afford it.   There is a lot to be said for doing what you can to reduce oil usage.
> 
> Let us know how it turns out.



Exactly.  The "spare cash and can afford it" part is where I have to wrap my head around the cost of the unit.  I actually love the idea, even if it were economically neutral if it saved energy.  I just have to convince myself I can afford it right now.

At the same time, in the next year or so, there may be vast improvements in the technology, so who knows what will happen.  I'm not in a huge rush, now that I have a plan. ;-)


----------



## OpenSky

Mike from Athens said:
			
		

> Keep in mind before you invest in one of these HPWHs:
> 
> 1.  They do work, and they do save a lot of electricity.
> 2.  The heating elements can heat up 50 gallons of water to 120 F in about an hour.  The HPWH will take two to three hours to do the same thing (depending on ambient air temp).
> 3.  The HPWH doens't keep your water at a constant setting like the electric elements.  Instead, you have a 15 F drop before it kicks on.
> 
> So, keeping in mind #3 above, consider this scenario (I went through this before in this thread, but I think it's important enough to reiterate).
> 
> HPWH runs and shuts down.  You now have 130 F water in the tank.  Run a load of laundry.  Run a load of dishes.  Kids take a bath that evening.
> 
> Now, you get up in the morning to take a shower.  The water is running for about 30 seconds, and the HPWH kicks on (this is the first time since the bath, dishes, and laundry).  After about 3 minutes in the shower, the water is still warm (comfortable, but not super hot).  You have about 2 more minutes to finish up.  After that, it will be somewhat cool.
> 
> Now, you really don't have hot water for about another hour or two.
> 
> Some may look at this as a big inconvenience, which I suppose it could be.  My family just has to adjust schedules.  Kids bath at night, wife showers at night.  I take mine in the morning.  We have a Bosch front load washer, GE dishwasher, both can heat it's own water if inlet temp is too low, so we run these at any time.  I think it's a small price to pay for huge energy savings.
> 
> EDIT:  one last point about the cost.  If you have to buy the HPWH AND a tank, both are components of the HPWH system, and both are eligible for the 30% tax credit.  IF you pay $1200 for the HPWH and $700 for the new tank, you can claim a $570 tax credit on your '09 taxes.  That's a good chunk of change.



I just installed a new AirTap A7 on a 62 gallon electric WH last weekend and re-engineered the thermostat setup by bypassing the thermostat in the A7 and using the lower heating element themostat instead.  First morning after the A7 install I woke up to 98 degree water and decided that wasn't going to cut it.  So far, I have 130 degree water at the closest tap about 10 ft. from the tank.  And now it makes no difference if the tank has been setting all day or all night with no usage, I still have hot water.  I think by using the thermostat that is lower on tank it can heat more consistantly since the cold will stay in the bottom of the tank and the thermostat on the tank is faster reacting.  I am new to the forum but I have enjoyed reading all of the input...Thanks


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## Wet1

Welcome to the forum OpenSky... and great idea!  I'm sure several people would appreciate and benefit from more details on how this is actually done, any more info or pictures would be great.


----------



## mikeathens

OpenSky said:
			
		

> I just installed a new AirTap A7 on a 62 gallon electric WH last weekend and re-engineered the thermostat setup by bypassing the thermostat in the A7 and using the lower heating element themostat instead.  First morning after the A7 install I woke up to 98 degree water and decided that wasn't going to cut it.  So far, I have 130 degree water at the closest tap about 10 ft. from the tank.  And now it makes no difference if the tank has been setting all day or all night with no usage, I still have hot water.  I think by using the thermostat that is lower on tank it can heat more consistantly since the cold will stay in the bottom of the tank and the thermostat on the tank is faster reacting.  I am new to the forum but I have enjoyed reading all of the input...Thanks



I thought about messing with mine, too.  I had the same thought about the supplied airtap thermostat bulb being toward the top of the tank...

I'm curious...does your unit kick on pretty much each time you draw a few gallons of water using the lower t-stat?  It seems that the lower tstat won't give you that 15 degree drop before it kicks on...and in fact, will only allow a couple degrees before kicking the unit on.  And I wonder if you use some of your efficiency/energy savings?  Just thoughts, and by no means do I necessarily know what I'm talking about.

Hey, if you could fill me in on how often the thing kicks on, I would appreciate it.  As mine stands, we get one shower, one load of dishes, and maybe a load of laundry before it turns on...and then someone might be "left in the cold", so to speak.  I was just thinking this morning how it would be nice to have a t-stat override button, so I could manually tun it on to reheat the whole tank while I'm gone at work...


----------



## Wet1

I'm sure the unit kicking on and off would cause a little drop in efficiency, but I doubt it would be enough to lose an sleep over.  These things are really nothing more than a basic window AC unit, and those turn on and off all the time.  Also, hot water demand/consumption is typically batched (in my household at least) so I doubt the unit would be kicking on and off all that often.  But you're correct, the more the unit kicks on and off, the greater the hit in efficiency.


----------



## mikeathens

I actually called airgenerate about this today...they emailed a tech sheet on the procedure for connecting to an external thermostat.  Not rocket science, but it is something they're aware of and have looked into.  So, according to them, I guess it's not a problem.  I think I'm going to do this, too (PITA...I just wrapped the thing in r-13 fiberglass and a lyer of foil bubble wrap).  This will probably change the on/off temp differential to 5 or 10 degrees, too.


----------



## OpenSky

By using the lower thermostat, the A7 does kick in rather quickly since the cold inlet water is streaming into the bottom of the tank. So the A7 runs until it can get the temperature back. I ordered a Kill A Watt today to track the electricity. The electric meter is spinning very slow with this thing running. It's just the wife and me at our household but, for two people we sure wash allot of clothes. We are using the Whirlpool Duet front load.  As far as lifestyle, I can't tell any difference between the heat pump and the elements....


----------



## mikeathens

This past saturday (April 11), I rewired the airtap to run on my water tank lower thermostat.  Now, after drawing a little water (let's call it 5 gallons) from the 40-gallon tank, the HPWH will kick on.  It runs more frequently now, but for less time each run.  Hearing the HPWH kick on doesn't mean we're about out of hot water now!

The hugest pain in the ass doing this was routing the wires out of the cabinet and to the thermostat.

Anyhow, it works!!  I think this is a much more effective way to run this thing.


----------



## OpenSky

I installed the Kill A Watt inline with the AirTap on April 10th.  My current electric contract I am paying 10.8 center per kwh.  It is showing my daily cost to run the AirTap is .62 cents.  So far so good!  This thing is working...


----------



## mikeathens

Uuuuuggghhh...I'm such a procrastinator.  I still have to get one of those kill-a-watt things.

So you're using about 5.75 kWh/day to heat water?  By my estimate, based on the energyguide included with my tank, I would be using aobut 14 kWh/day if I used the in-tank elements.  If mine also shows about 6 kWh, I'll be pretty happy (two kids + me and my wife using hot water).  6 kWh will be about 25% of my solar array output on a good, sunny spring day.


----------



## diyer

Make sure you run through the numbers before you buy.

Assuming a 50 gallon tank, 50F to 100F rise.  50F * 8 lbs/gallon = 400BTU's.

Most AC/dehumidifiers are probably 5000 to 12000 BTU's.  Also as you have a closed system, the temp delta between the water and cellar will increase, causing loss of efficiency.

You  may make it if you use 500-1000 gallons of hot water / day.

My guess is you would be best trickling the hot water all the time,  but where is the savings?

Carl


----------



## DBoon

> Assuming a 50 gallon tank, 50F to 100F rise.  50F * 8 lbs/gallon = 400BTU’s.
> 
> Most AC/dehumidifiers are probably 5000 to 12000 BTU’s.  Also as you have a closed system, the temp delta between the water and cellar will increase, causing loss of efficiency.
> 
> You may make it if you use 500-1000 gallons of hot water / day.



1 BTU = the amount of energy to raise 1 lb. of water 1 degree Fahrenheit.  
So a 50 gallon tank has 400 lbs. of water (50 gal * 8 lbs./gal) and to raise that 50 degrees F would take 20,000 BTUs (50 degrees F * 400 lbs.)  What you indicated would be true if the temperature was only raised 1 degree F. 

There are 3.414 kW/BTU, so this would mean about 6 kW of electricity.


----------



## diyer

Oops.

Well at least the numbers have been gone through.  Sorry for the dropped delta T.

Carl


----------



## DBoon

No problem.  There are two kinds of posters - those who have already made a mistake, or those who will.


----------



## diyer

Can I hijack the thread a little?

I am looking at storing cold in my thermal store and using it for air conditioning.  I am looking for recommendations.

I have a Tarm pressurized system in an outside storage unit.  This runs a heat exchanger loop into an unpressurized 1500 gallon insulated milk tank. There is another loop for heat(forced air) and DWH.

I currently use 2 window airconditioners during the summer.  They run continuously during the day.  I'm guessing that they are about 20K BTU's total (about 1.5 tons).  If I find a water-to-water heat pump, I can run the hot side through my DWH superstore, continuing outside to the boiler loop(boiler off).  This would heat my water and dump excess heat outside.  The cold side would be put through the heat exchangers in the 1500 gallon tank.  I will be running Propylene Glycol in the system and would like to get down to 25F or so on the cold side.

The cooler temperatures in the evening with some radiational cooling will allow me to harvest the cold "off peak".  During the daytime, I would pump the cool out through a heat exchanger into the forced air system.  It would be sweet to add off peak electric rates for this if I can get them.

I would also like to swap the hot/ cold loop and heat the tank with the daytime temps during spring and fall for use during the colder evenings.

Does anyone know of a water to water heat pump in the 1 - 1 1/2 ton(12K - 18K BTU's) range?

Also, I was wondering what the best coil arrangement would be for this water cooled "chiller".  I currently have a hot water coil in the up flow furnace plenum for heating.  I may want to find a chiller to put in above the current coil.  This would have the cold added at the top, flowing downwards, possibly plumbing the hot water coil in also.

I don't know how to add the condensate drain pan under the coils in the up flow.  It seems like the pan would block the air.

Another concept would be to buy a downflow or side flow heat exchanger and place it before the furnace.  This could have the drain pan on the side of the furnace.  I could plumb the hot water coil, but it would be last in the cooled water loop to avoid condensation on it.

I would really like to have the first solution (all coils in the furnace plenum).  This would be the same plumbing for heating and cooling.  Also with the extra cold water coil, I could get more heat out of it during the winter.

All of my coils/plumbing is 1" PEX.  My Tarm boiler is in a storage container.  I am considering adding a solar exhanger to the side of the container.  This would add to my daytime heat gain for hot storage, and the radiational cooling during the cold storage season.

This is really just a geothermal heatpump, but only using the diurnal ranges for short term storage.

Thanks
Carl


----------



## Wet1

diyer, start a new thread for your questions.  You're way off topic and you'll get little or no response within this thread.


----------



## jh6u

Back to the HPHW topic:
I've been comparing the Geyser to the Airtap:
A neighbor has the Airtap; it works well, except that he has had icing problems.  He's fixed it by running a 100w lamp in parallel with the unit to heat the condensor, a kludge at best.  The better solution is that the newer units apparently include an anti-icing sensor.  I have two concerns with this unit: 1) It apparently doesn't have UL certification: I haven't been able to find out whether this would be an issue with homeowner's insurance if there were to be a problem/fire.  2)  It seems that it's a tight fit to get the heating tube into the tank.  My neighbor commented that it would be difficult to get this out once it got crudded up.  I worry that the lifetime of the unit would be limited by the time to tank failure.

The Geyser: more expensive, but I've been more impressed with the engineering, at least on paper.  It includes an anti-icing cycle.  It works by replacing the lower electric element- so the upper electric element is still there as backup in case of high demand.  I suspect this is why they can claim such a high first hour rating.  It also looks to be much easier to take out of an old tank.  So I'm leaning towards the Geyser.

We have a great setup for this- a 1000 sq ft unfinished basement, so lots of area to transfer heat from soil.  By my calculations, this should only take ~200 sq ft.

I'd appreciate feedback, especially on the insurance/UL issue.
Thanks all for an interesting forum thread.


----------



## mikeathens

JayH said:
			
		

> Back to the HPHW topic:
> I've been comparing the Geyser to the Airtap:
> A neighbor has the Airtap; it works well, except that he has had icing problems.  He's fixed it by running a 100w lamp in parallel with the unit to heat the condensor, a kludge at best.  The better solution is that the newer units apparently include an anti-icing sensor.  I have two concerns with this unit: 1) It apparently doesn't have UL certification: I haven't been able to find out whether this would be an issue with homeowner's insurance if there were to be a problem/fire.  2)  It seems that it's a tight fit to get the heating tube into the tank.  My neighbor commented that it would be difficult to get this out once it got crudded up.  I worry that the lifetime of the unit would be limited by the time to tank failure.
> 
> The Geyser: more expensive, but I've been more impressed with the engineering, at least on paper.  It includes an anti-icing cycle.  It works by replacing the lower electric element- so the upper electric element is still there as backup in case of high demand.  I suspect this is why they can claim such a high first hour rating.  It also looks to be much easier to take out of an old tank.  So I'm leaning towards the Geyser.
> 
> We have a great setup for this- a 1000 sq ft unfinished basement, so lots of area to transfer heat from soil.  By my calculations, this should only take ~200 sq ft.
> 
> I'd appreciate feedback, especially on the insurance/UL issue.
> Thanks all for an interesting forum thread.



Well, I'm not sure about the UL rating issue.  I would suggest calling Airgenerate.  I'm sure they could answer any question you might have.  Their customer service has (so far) been excellent to me.  If I remember, I'll have a look at the unit to see if I can find any UL label.

I had no issue getting the heat exchanger/tube in the tank, and I can't forsee any issue removing it in the future.  I would expect the unit to fail before my tank does.  The one issue I did have with it was the tank be ing nearly out of hot water before the unit kicked on.  I solved this by wiring it to the lower thermostat and disabling the supplied bulb.

Icing has not been an issue whatsoever for me.  The low ambient operating temperature has been in the low 60's.  I would assume that your neighbor has been operating his in a cooler basement, maybe in the low 50's range?  If so, I would imagine this will be an issue with any of these types of units.  Running in a colder room will cut way back on efficiency.  Deicing will cut back even more.  Runnning a 1500-3000 Watt in tandem with one of these will really put the hurt on your savings (like using the upper element).

Since I've rewired to the lower t-stat, my airtap has supplied all of the hot water we've needed for my family of four.  So far, no complaints.  Now that the temps are climbing into the 80's outside, my house is warming up, too.  That air from the airtap that made the bathroom a little chilly a couple months ago sure feels good now!!


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## jh6u

Here are direct quotes I've gotten from each company: I'd appreciate some help with interpretating these & how these certifications relate to National building codes & insurance coverage:

AirGenerate:
"The AirTap has multiple industry certifications: NTS (National Technical
Systems), GAMA (Gas Appliance Manufacturers Association, which recently
merged with AHRI, the Air-Conditioning, Heating and Refrigeration
Institute), and CSA, and we are in the process of getting Intertek (ETL)
certification, too."

North Road Technologies:
"QPS has performed our UL and CSA Certification compliance in accordance with QPS/SGS Listed (UL-1995 / CSA C22.2 No. 236).  This is “guaranteed UL compliant”."


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## mikeathens

Airgenerate emailed their label to me.  It does mention UL standard.  Unfortunately, I don't know what it all means.


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## Gooserider

Mike from Athens said:
			
		

> Airgenerate emailed their label to me.  It does mention UL standard.  Unfortunately, I don't know what it all means.



What the testing stuff means is that the unit was NOT tested by "UL" itself, but by a 3rd party testing lab, which is fairly common practice, as UL does very little testing itself.  The test lab is "ETL" - couldn't read the label enough to see what that stands for, and they tested it to a set of listed UL (United States) and CSA (Canadian) standards - The numbers are the ones that the respective agencies think are needed for the particular type of device.  For all intents and purposes, this is the equivalent of "UL Listing" - it should keep insurance companies, code inspectors and so forth all happy as long as the product is installed and used in accordance with the mfgr directions...

Also keep in mind with ALL products - UL, CSA, or other safety agency listings do NOT make any promises about a product working, doing what it says it will, efficiency, or other such things...  The ONLY thing they promise is that the product (probably) won't do anything in normal operation, or break down, in a way that will cause your insurance company (i.e. the "Underwriter" in "Underwriter's Lab") to have to pay out any cash - i.e. it won't fry you, burn your house down, and so forth...  IOW, it doesn't have to work, it just has to not hurt you...

Gooserider


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## egghead2004

Any updates in savings?
I'm trying to convince DW that these will save $$$ over the next few years.

Thanks,


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## jh6u

I ended up going with the Airtap.  

The Airtap is working well in our installation; with summer basement temperature ~70F, I measured an Energy Factor of ~4.1 for the initial tank heat-up; this will decrease to ~2.5 with winter basement temps in the 50's.  Installation was complicated by that fact that the hot water stub wouldn’t come out- my plumber thought it was welded in, as he's seen in other cheap retail-store tanks; so we needed a new tank.   Advice for other installations- soak the hot water stub threads with PB Blaster for a few days in case they’re seized.  I had the connections all ready to go for the installation- installing the new tank and Airtap took the two of us only ~30 min.  The units now shipping have an anti-icing switch, a longer thermostat run, and a 10F delta thermostat; together these updates seem to get around the problems with earlier units.

Payback time is a bit longer than the 2-3 years that I was hoping for- probably ~5-6 years, due to added cost of new tank, and the fact that we're only using ~half the hot water/day that I had expected.  We need to take more/longer/hotter showers!  But it's no noisier than our dehumidifier, which we no longer run, and we have a drier basement to boot.


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## gpcollen1

http://www.northrdt.com/Geyser_Product_Technical_Data.html

JUst saw this unit when looking for the Nyletherm site. Hopefully I won't need a new one for a while...


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## egghead2004

The Geyser, yep, that's what I'm looking at. The airtap won't fit to my Amtrol tank. The Geyser will however. Just wondering if DIY will qualify for the tax credit, but thats another post.


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## CarbonNeutral

It worries me that the AirGenerate website does not mention the new non-icing product. Equally, they have removed their forums which had a lot of complaints about icing. Finally, and this I think is just poor marketing - their "calculate their savings" does not include an 'oil tankless' and 'oil suprastore' option, plus their electric cost is way higher for me than it should be (0.17 compared to mine of 0.125/kWh all in). 

I really like the idea of their product, but frankly their marketing just sucks - as this is my only real way to judge them, it makes me think twice...


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## tom in maine

We have installed an Airgenerate unit and recently a Geyser.
The AirTap has icing problems in cooler basements. 

The Geyser is quite quiet and I think you get what you pay for.

We are thinking seriously about offering them (The Geyser, that is) as an option with our tanks as a backup for wood and solar.

I believe they are eligible for the rebate as a DIY project.


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## Redox

Any idea what the MSRP is on one of those Geysers?  Their website is kinda light on details and some of their numbers look a little puffy to me.  Thanks.

Chris


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## tom in maine

They retail for about $1400.


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## Wallyworld

Tom in Maine said:
			
		

> They retail for about $1400.


Wow
I bought my Nyletherm for less than 600 on sale, thats quite a jump in price


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## tom in maine

Yes that is quite a jump. The older units were retailing for $1,000. The $600 units were refurbs that they blew out. That was a great deal.

I can tell you that the new ones are quieter and smaller. I believe they perform the same, but are plug in 110v instead of the more complex 220v system that was not simple to make work with anything other than an electric hot water tank.

Compared to the Airtap, there is a lot more under the hood.

I guess you get what you pay for.
Tom


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## bzockoff

I've been lurking and think the details the rest of you have given this topic is great. 

I just saw a pre-mo for a GE unit. I guess they are finally taking this market as a good energy saver. See:

http://www.geappliances.com/products/water/heat-pump-water-heater/?cid=14249&omni;_key=(b)Non-Brand_|_Water_Heater-heat_pump_-Heat_pump_water_heater

I'm also concerned about using the Airtap with teh tank coils active, since the copper heat exchanger could be in contact with them. THis might be a reason that they are having trouble getting UL approval. 

BobZ
-----------------------------------------------------
No solar or geothermal, but just starting


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## tom in maine

It is my understanding that the hx on the Airtap is single wall and it will not pass UL nor some code jurisdictions since a breach of the hx will put refrigerant oil into the potable water.
That would be less of an issue with our tank since we would have an effective double wall to potable, but I don't want oil on our liner.


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## jh6u

We've had the Airtap now since late-June.  In response to numerous pre-purchase queries, I got the following from AirGenerate:

"The AirTap has actually always been double walled and continues to be so.

The AirTap meets UL certifications, but is not yet certified.   The AirTap
has multiple industry certifications: NTS (National Technical
Systems), GAMA (Gas Appliance Manufacturers Association, which recently
merged with AHRI, the Air-Conditioning, Heating and Refrigeration
Institute), and CSA.

NTS TR-301499-06C applies, the unit is certified to CSA standard C22.2 No.
236, and the AirTap is safety certified by ETL/Intertek with UL-1995
standards."

As I mentioned earlier, I'm not expert in evaluating these statement.

The Airtap manual states that the power to the elements in the main tank should be permanently disconnected; I suspect, as mentioned above, they don't want close contact between the hot elements & their freon line.

Also, in response to previous posts, the currently shipping units (mine included) have an anti-icing switch.  It's no noisier than our (now unused) dehumidifer.

We've only used it in summer, but to date, we'm very pleased with the results, & we're on track for a ~4 year payback time.


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## craigsward

I'm looking to get an airtap unit soon.  I will replace my 40 gallon electic HW heater with an 80 gallon (we have a large 60 gallon whirlpool tub so this needed to be done anyways).  I will also probably do the same modification to use the tank thermostat to make sure the unit keeps up with heating water regularly.  I imagine it would take quite some time for the airtap to heat 80 gallons back up to temp, so it seems like although this will affect efficiency, the thermostat is a must for people who require hot water at most times during the day.  Has anyone figured out how much more electricity they are using by doing this modification versus using the airtap Tstat?

I have a pellet stove in the down stairs, where the furnace and water heater are located, so ambient should be pretty toasty down there.  I also have an unused refrigerator in my furnace room, so i'm thinking of feeding the cool exhausted air into the refrigerator in the winter months, and then i'll undo this in the warm months.  Maybe it will even get cold enough to keep some beverages cool.
My ultimate goal is to put in a good size sollar collector array for DHW.  However i probably won't get around to this for a couple years.  I can then rely on the airtap unit as my solar backup.  So in the interim i feel this airtap unit is a good investment, with realtively quick paypack.  I can get the airtap for 599, and then the new 80 gallon HW heater for 150.  Plus the 30% tax credit, it almost seems like a no brainer.

Does anyone see holes in my plan or want to provide some further insight on real world gained efficiencies they are seeing with their airtap or geyser?


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## jh6u

Currently shipping Airtap units, mine included, contain a longer thermostatic probe than earlier ones- so use of the tank thermostat may not be necessary.  Check with them.

7K BTU translates into something like 12 gal/hour water heated to 120F.  If your needs are occasionally higher than 92 gal/hour, perhaps keep your current tank, putting the Airtap equipped tank first as a preheat, with the older tank in series set at lower setpoint to provide extra capacity.  A neighbor has done this & it works well.


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## CarbonNeutral

JayH said:
			
		

> We've had the Airtap now since late-June.  In response to numerous pre-purchase queries, I got the following from AirGenerate:
> 
> "The AirTap has actually always been double walled and continues to be so.
> 
> The AirTap meets UL certifications, but is not yet certified.   The AirTap
> has multiple industry certifications: NTS (National Technical
> Systems), GAMA (Gas Appliance Manufacturers Association, which recently
> merged with AHRI, the Air-Conditioning, Heating and Refrigeration
> Institute), and CSA.
> 
> NTS TR-301499-06C applies, the unit is certified to CSA standard C22.2 No.
> 236, and the AirTap is safety certified by ETL/Intertek with UL-1995
> standards."
> 
> As I mentioned earlier, I'm not expert in evaluating these statement.
> 
> The Airtap manual states that the power to the elements in the main tank should be permanently disconnected; I suspect, as mentioned above, they don't want close contact between the hot elements & their freon line.
> 
> Also, in response to previous posts, the currently shipping units (mine included) have an anti-icing switch.  It's no noisier than our (now unused) dehumidifer.
> 
> We've only used it in summer, but to date, we'm very pleased with the results, & we're on track for a ~4 year payback time.



Can I ask why you are only running it in the summer? If it's saving you money in the summer by not using oil, the same is true in the winter. Just because your furnace is running, doesn't mean that the HW is now free. I'm sure there are some slight efficiencies as the furnace will run for longer typically, and your airtap will be less efficient as basement temps will be lower, but would be interested in your take on this.


----------



## jh6u

> Can I ask why you are only running it in the summer? If it's saving you money in the summer by not using oil, the same is true in the winter. Just because your furnace is running, doesn't mean that the HW is now free. I'm sure there are some slight efficiencies as the furnace will run for longer typically, and your airtap will be less efficient as basement temps will be lower, but would be interested in your take on this.



Sorry- we only had it installed this summer.  I'm expecting that with winter basement temps in the low 50's that efficiency will drop to ~2.5, which is still quite good.


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## CarbonNeutral

JayH said:
			
		

> Can I ask why you are only running it in the summer? If it's saving you money in the summer by not using oil, the same is true in the winter. Just because your furnace is running, doesn't mean that the HW is now free. I'm sure there are some slight efficiencies as the furnace will run for longer typically, and your airtap will be less efficient as basement temps will be lower, but would be interested in your take on this.
> 
> 
> 
> 
> Sorry- we only had it installed this summer.  I'm expecting that with winter basement temps in the low 50's that efficiency will drop to ~2.5, which is still quite good.
Click to expand...


Got you. 

I've seen enough posts here from people thinking that DHW is free if their furnace is running anyway.


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## Gooserider

CarbonNeutral said:
			
		

> JayH said:
> 
> 
> 
> 
> 
> 
> 
> Can I ask why you are only running it in the summer? If it's saving you money in the summer by not using oil, the same is true in the winter. Just because your furnace is running, doesn't mean that the HW is now free. I'm sure there are some slight efficiencies as the furnace will run for longer typically, and your airtap will be less efficient as basement temps will be lower, but would be interested in your take on this.
> 
> 
> 
> 
> Sorry- we only had it installed this summer.  I'm expecting that with winter basement temps in the low 50's that efficiency will drop to ~2.5, which is still quite good.
> 
> Click to expand...
> 
> 
> Got you.
> 
> I've seen enough posts here from people thinking that DHW is free if their furnace is running anyway.
Click to expand...


It seems possible to me depending on the setup and so forth that while the DHW wouldn't be "free" if the boiler were running anyway, it might be the case that it would be less than running an airtap or other form of water heating...  I suspect that this would be something that each person would need to work out for themselves as it would depend on just how the furnace water heating was set up.

Gooserider


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## CarbonNeutral

Gooserider said:
			
		

> It seems possible to me depending on the setup and so forth that while the DHW wouldn't be "free" if the boiler were running anyway, it might be the case that it would be less than running an airtap or other form of water heating...  I suspect that this would be something that each person would need to work out for themselves as it would depend on just how the furnace water heating was set up.
> 
> Gooserider



You could be right - perhaps the cold water in the DHW part of the boiler helps pull more heat out that doesn't go up the flue, but at the end of the day you have to use X BTUs to heat X gallons of water. Certainly in my system (tankless oil) I would still be far ahead with even a normal electric heater.


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## tom in maine

I  think I mentioned that I have both the Nyletherm, an Airtap and now a Geyser.

The Airtap is installed at my daughter's house and we had the discussion about shutting it down soon, or expecting the unit to freeze up as it gets colder out.
This is what it does when it gets cold out and will not work consistently in the winter in her basement.
A basement with a wood stove or boiler would not be a problem.

The Airtap is not UL listed, and I suspect, it will not be. The heat exchanger is not double walled. It is about 1/4" in diameter, so how is this double walled?

Meeting UL certifications is not UL listed. 

Of the three units, the Geyser is the most expensive and I think it offers the most advantages. It is double walled and UL listed. It also lists for $1400.
It is quieter than the other two and can be re-used from tank to tank.

I worry that the Airtap hx will fail with aggressive well water.

In full disclosure, you should know that we are offering the Geyser on our website. You can't beat the Airtap price, but for how long?


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## Wallyworld

Ghettontheball said:
			
		

> nyle 220v@$800 went to geyser 110v@$1400?


Yes
with some changes that makes it easier to install in most any tank


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## tom in maine

Yes, it is quite a spread. The Nyletherm actually retailed for $1000, but they regularly had discounted refurb units that went from $6-800.

If you were installing it with anything other than an electric water heater, you had to do some odd jerry rigging with a resistor.
I took my unit back to Nyle because I was sure that I blew out the controls.
Fortunately it is more robust than that and they got it set up for me. I was the first person to use it without a standard electric heater, I guess.
I have used it for three years and it works great. 
The Nyletherm is no longer available as the Geyser replaced it.


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## Wallyworld

Tom in Maine said:
			
		

> Yes, it is quite a spread. The Nyletherm actually retailed for $1000, but they regularly had discounted refurb units that went from $6-800.
> 
> If you were installing it with anything other than an electric water heater, you had to do some odd jerry rigging with a resistor.
> I took my unit back to Nyle because I was sure that I blew out the controls.
> Fortunately it is more robust than that and they got it set up for me. I was the first person to use it without a standard electric heater, I guess.
> I have used it for three years and it works great.
> The Nyletherm is no longer available as the Geyser replaced it.



They gave me the wrong wiring diagram when I got mine. I had it wired the way they said and nothing. Called them up and finally got the right diagram from Don himself. I'm on my 3rd year also. Of course I heard about it on your radio show


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## EricV

Ok, so where are we finding the best price for this unit?  The Airgap I mean.


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## UB777

Hi,

I am new to this forum, and found it doing searches for information on the A7 Airtap. Are there any longer term reports on the A7, or new purchasers that would like to share there experience with the A7?

Thank You
UB777


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## jh6u

We've had our Airtap A7 since last June.  It's working well, even when our basement temperature dropped to 50F in the dead of Central Virginia winter.  My calculated efficiency rating was ~2.5 in winter, ~4 in summer with 68F ambient temperature.  We've only run out of hot water once, with a daughter's long shower in the cold of winter.  If you have heavy bursts of use & an older hot water tank, my recommendation would be to buy a new tank on which to install the A7, & connect in series before the existing unit, turning down the temp setting on the old unit so it only comes on during periods of heavy use.  But overall I'm very pleased.

Jay


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## UB777

Jay,

Thank you for the reply.

I just replaced my EWH, I cannot be disappointed in the service I received, it is the original that was installed when my house was built in 1979. All I did was drain and flush the tank every year, and I had to replace one thermostat and a fill/drip tube.

I live in North Texas and my WH is in my garage where the Temperature in the summertime is 80 to over 100 F, so the A7 should be very efficient that time of year. I thought about pulling the lower element during installation of the A7 to verify that that the refrigerant line will not contact the element,  and possibly after x amount of A7 run time allow the elements to turn on and finish the job, and or let them both run during high demand situations, when I have company. I looked at my tank and I have room to install a second lower thermostat to control the A7 if necessary.

At this point I am still researching to decide to purchase or not.

Thank you

UB777


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## John H

I just installed the AIRTAP-A7 yesterday. The install was easy,it blows ice cold air that I hooked to an AC register,it removes moisture from the basement and the hot water is plenty hot.
  I purchased it from Wam Home center. I paid 519.00 delivered. There price has gone up $625.00 delivered,I also bought the adapter to hook up to the AC. The adapter made the hook up very easy. The adapter was $75.00.

    John


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## Baston8005

I'm in the process of looking at the Geyser setup.  I have a 1000 sq ft basement where I will install this system.  My house has electric heat which I used 1 winter only...After that winter I went out and bought a pellet stove.  I run a dehumidifier all year long in my basement also.  This combined with my electric water heater is killing me!  I see a few guys are using the airtap system.  Whats the difference between the two systems?  I have watched the geyser install video and it seems like a straight forward install...quite easy actually.  Price difference's?   Any input would be greatly appreciated.


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## tom in maine

Both perform about the same. 
There are/were? some issues with the Airtap freezing up in the colder weather.
THe Airtap is about half the cost of the Geyser. The Geyser can be moved from one tank to another, in case the tank ever leaks.
The Airtap might not move from one tank to another since the heat exchanger is a very thin copper hairpin tube that is inserted into the tank.

I have installed both. The Geyser is definitely a case of you get what you pay for.
I guess the Airtap is too...


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## Baston8005

I contacted Geyser and found that unit is selling for $1073 plus tax.  Much lower than a few people have told me.  Looks like a good fall project.


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