# Geyser DHW owners



## hemlock (Jul 29, 2012)

Hello,
Are there any Geyers HPWH owners here?  I am seriously considering getting one, but would like to here from a few owners, and perhaps ask a few questions.  From what I've read here and elsewhere, they seem to get good reviews.  Specifically, I would like to here from owners how much heat they were "losing" from the room where it is located by running the unit.  Any input would be great.  Thanks.


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## woodgeek (Jul 29, 2012)

IMO, old tech. The 'all-in-one' HPWH units are supposed to have better performance, i.e. COP.

The answer to your question depends on the size of the space where it is located.  Figure that half the BTUs that end up in the water come from the space, the other half come from the grid (i.e. COP ~2).


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## Slow1 (Jul 29, 2012)

woodgeek said:


> IMO, old tech. The 'all-in-one' HPWH units are supposed to have better performance, i.e. COP.
> 
> The answer to your question depends on the size of the space where it is located. Figure that half the BTUs that end up in the water come from the space, the other half come from the grid (i.e. COP ~2).


 
Even old tech has its place... I'm considering one as well.  I have a nice oil boiler heated tank - it basically can not be run cold in our home (run 2 showers at same time as laundry and nobody notices).  Given the recovery time of a pure HP solution I would need a much larger tank.  Never mind the cost - simply replacing the tank and going all electric (even if HP) isn't my preferred option here so using something like the Geyeser may well do the trick for me (is there another option for add-on btw?).

What I desire to do is have the ASHP keep the tank hot and cover minor use, then have the oil set point a few degrees lower to insure that it won't fall too low during peak demand times.  I currently have a surplus of electric production so that would likely reduce my overall fuel costs...


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## GaryGary (Jul 30, 2012)

hemlock said:


> Hello,
> Are there any Geyers HPWH owners here? I am seriously considering getting one, but would like to here from a few owners, and perhaps ask a few questions. From what I've read here and elsewhere, they seem to get good reviews. Specifically, I would like to here from owners how much heat they were "losing" from the room where it is located by running the unit. Any input would be great. Thanks.


 

Have you seen Tom's entertaining video on installing one?  

Gary


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## hemlock (Jul 30, 2012)

Thanks for the info so far.  Does anyone know of a good place to order one from, and roughly what they should cost?  I have heard and seen anywhere from $1000 to $2000 - quite a variance.  Thanks again,


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## Redbarn (Jul 31, 2012)

I have one. Bought it about a year ago from Tom in Maine (americansolartechnics.com).
Have run it for over a year now and it works great.
We were using 1 gallon of oil a day to heat our DHW.
The Geyser increased our electric bill by circa $15 per month but saves us 30 galls of oil a month. 
Coupled with the $300 with the tax credit, it has paid for itself already.

I installed it in parallel with our current 80 gall oil water heater.
Just switched off the oil burner and used the Geyser.
If we get a house full of people, just turn the oil burner on and use both.

Installed it in our basement.
I ran a temperature probe attached to a data logger in the basement. 
Recorded the basement air temp at 2 hour intervals all year.
Basement high temp was 74 deg in July and a surprising 59 deg in February.
Kinda Geothermal heating I suppose.
The Geyser has run 24/7 for 15 months now.
The COP dropped a bit in Feb with 60 deg air temp but the electric bill barely changed.

I connected the air in + out to some air vents in a room on the first floor in summer.
Used these as a dehumidifier/air conditioning.
The wife soon learned to run laundry in the afternoons to cool a chunk of the first floor.
For winter, these vents were shut off and the Geyser used basement air.

Water recovery is Ok if you plan a little.
Mornings showers just about empty our 80 gall tank (3 adults). Geyser recovers it by mid afternoon and the system can handle home from work showers. It runs till late evening and has 80 galls ready for next day.

All in all, so far so good.


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## Slow1 (Jul 31, 2012)

Redbarn said:


> I have one. Bought it about a year ago from Tom in Maine (americansolartechnics.com).
> Have run it for over a year now and it works great.
> We were using 1 gallon of oil a day to heat our DHW.
> The Geyser increased our electric bill by circa $15 per month but saves us 30 galls of oil a month.


 
Thank you for sharing your experience!

Can you tell me what your cost/Kwh is?  What I'm getting at here is an estimate of how many KWh you are burning with it each month (I can then more accurately project onto my own situation).

Thanks.


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## Redbarn (Jul 31, 2012)

Slow1 said:


> Thank you for sharing your experience!
> 
> Can you tell me what your cost/Kwh is?  What I'm getting at here is an estimate of how many KWh you are burning with it each month (I can then more accurately project onto my own situation).
> 
> Thanks.


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## Redbarn (Jul 31, 2012)

We live in PA which has a "market" electricty supply. Our current cost is $0.134 per kWr but this has dropped throughout our Geyser ownership.

As for kWh used by the Geyser every month, I've never bothered to break it out accurately. Too many other changes to specifically itemize it.
I think its a case of "your mileage may vary" in that household use, household size, intake water temperature etc. will have a significant effect on kWh used.
Besides, we are saving $100 a month over oil use so I wasn't worried about a kWh or two.

I was concerned about feeding it  warm air and thus keeping the COP up.
Hence my temperature monitoring. I thought it would run April through October but was pleasantly surprised to find that the basement was warm enough to feed it year round.


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## Slow1 (Jul 31, 2012)

Redbarn said:


> As for kWh used by the Geyser every month, I've never bothered to break it out accurately. Too many other changes to specifically itemize it.
> I think its a case of "your mileage may vary" in that household use, household size, intake water temperature etc. will have a significant effect on kWh used.
> Besides, we are saving $100 a month over oil use so I wasn't worried about a kWh or two.
> 
> ...


 
How are you calculating and/or otherwise monitoring COP?  

In any case, if you are in fact burning about $15/mo average in electricity (as you reported initially) with a cost of 13.4c/Kwh then it would seem you are running about 112Kwh/mo.  Now, I'm a bit confused about this as it seems that at about a 41:1 ratio (139Kbtu/gallon oil:3.4Kbtu/Kwh) this would imply that you are using enough electricity for about 3 gallons of oil a month.  Either the estimates on how much electricity the Geyser is using is far too low, your oil offset is too high, or you have one seriously inefficient oil heater there.  Perhaps I miscalculated somewhere...

Working the numbers the other way, if your oil burner is running at say 60% efficiency to heat that water, then I would expect that it would take about 736Kwh/mo for a resistive electric to equal out to your 30 gallons of oil (hopefully your oil system was better than that, but..).  Now if the Geyser runs at the COP 2 that it claims then it should burn about 1/2 that - so about 368Kwh which would likely boot your electric bill up about $48/mo.  Still not bad considering you estimate that the oil was running about $100/mo.  Of course if that oil system runs at 80% then the equivalent electric would be about $67/mo, still a savings but it is narrowing that gap rather quickly.

Understand that I'm not trying to nit pick your statements; rather as someone seriously considering the purchase of a Geyser I really do want to understand how well it runs not just from the "can it heat the water" but also how efficiently does it run - meaning how much electricity will it likely burn over time in a real-world situation such as what you have described.


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## Redbarn (Jul 31, 2012)

I cannot provide the information that you are requesting.
I am certainly not going to comb through the minutae of my electric bills to do so.

I suggest that you contact the manufacturer and get their data. This coupled with some measurements of your usage should get close to answering most of your questions.

The OP asked for experiences of existing users. I provided that.


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## woodgeek (Jul 31, 2012)

Slow1 said:


> How are you calculating and/or otherwise monitoring COP?
> 
> In any case, if you are in fact burning about $15/mo average in electricity (as you reported initially) with a cost of 13.4c/Kwh then it would seem you are running about 112Kwh/mo. Now, I'm a bit confused about this as it seems that at about a 41:1 ratio (139Kbtu/gallon oil:3.4Kbtu/Kwh) this would imply that you are using enough electricity for about 3 gallons of oil a month. Either the estimates on how much electricity the Geyser is using is far too low, your oil offset is too high, or you have one seriously inefficient oil heater there. Perhaps I miscalculated somewhere...
> 
> ...


 
Slow, its all about standby.  I too was burning about 0.8 gal/day of #2 to keep my boiler hot for DHW, but prob delivering a tiny fraction of that as DHW BTU out a tap.  The rest was making my AC run more during the summer.  SInce I went to the HPWH, my elec bills are net **lower**, presumably because I have shut off my garage dehumidifier (now handled by the unit), and my AC is running a lot less (b/c my boiler has been scrapped).


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## woodgeek (Jul 31, 2012)

The test reports I have read suggest that the AO Smith and Steibel Eltron consistently get a COP a bit over 2 in a conditioned space, while the geospring and retrofit units are a bit worse.  The problem comes down to difficulties with optimal control and lack of stratification.  IOW, the all in one units use stratification to get higher COP....a lot of the BTUs are pushed into a low temp reservoir at COP>3, and the last few BTUs to finish the tank have lousy COP.  A system that that is recircing a well-mixed, always hot reservoir is at a big disadvantage.


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## Redbarn (Aug 1, 2012)

I can verify that when using the Geyser air in/out to cool part of our first floor in the summer that our electric bills went down. Significantly. The A/C kicked on a whole lot less.

For us the retrofit was cost effective in that we did not have to replace a perfectly good oil DHW unit.
Just added a Geyser and used some pex.

For sure an "all in one" unit should be more efficient but if you have an existing system, I doubt the difference in efficiency and potential operating cost would ever recover the larger installtion costs.


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## woodgeek (Aug 1, 2012)

Sure.  My unit costs $2200 retail and I had it installed by a plumber.  I assume you got the geyser for half that and put it in yourself.  Even with a couple pips difference in the COP I will never get caught up to you $$-wise.  In my situation, I didn't already have a tank, could get a rebate, and needed a plumber to run the new lines, so a new geyser+nice tank would have cost me the same amount.

As for Slow's question....your boiler went from hot 24/7 to cold, and you are only heating an (indirect) tank with the geyser??  Do you think the reduced AC could be partially from the lower standby heat of the boiler? A gallon a day of oil is ~5000 BTU/h, the same as a space heater on high or a small window unit AC running 24/7.


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## Slow1 (Aug 1, 2012)

woodgeek said:


> The test reports I have read suggest that the AO Smith and Steibel Eltron consistently get a COP a bit over 2 in a conditioned space, while the geospring and retrofit units are a bit worse. The problem comes down to difficulties with optimal control and lack of stratification. IOW, the all in one units use stratification to get higher COP....a lot of the BTUs are pushed into a low temp reservoir at COP>3, and the last few BTUs to finish the tank have lousy COP. A system that that is recircing a well-mixed, always hot reservoir is at a big disadvantage.


 
So in the case of the recirculating (such as I believe the Geyser falls) you are essentially getting more hot water ready and waiting and 'paying' with a lower efficiency rating. The other aspect that I imagine must come into play though is the question of heat loss in the connection between the storage tank and the heating unit. Integrated units don't have much to worry about; external units however will have greater losses here. I'm surprised that the installation videos I've seen for the Geyser have not shown insulation on these pipe runs - at least on the hot water side as I imagine it would make a difference.


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## Slow1 (Aug 1, 2012)

woodgeek said:


> Slow, its all about standby. I too was burning about 0.8 gal/day of #2 to keep my boiler hot for DHW, but prob delivering a tiny fraction of that as DHW BTU out a tap. The rest was making my AC run more during the summer. SInce I went to the HPWH, my elec bills are net **lower**, presumably because I have shut off my garage dehumidifier (now handled by the unit), and my AC is running a lot less (b/c my boiler has been scrapped).


 
No doubt that when you can get the secondary benefits (retire a dehumidifier) the energy benefits are magnified significantly.  I don't currently run one but I don't think it will hurt to pull some moisture out of the air during the summer either.

As to standby - I do wonder exactly how my oil boiler works.  IF the zones don't call for heat I don't ever hear it firing up (I would as it has quite a fan on it to provide draft).  Thus although it does kick on periodically, it is generally when we have used some hot water and lowered the temp in the HW tank (not every time though - depends of course on how much HW we use).  Occasionally it may kick on to re-heat the tank due to the tank cooling on it's own - but that is not too common.  So, my my conclusion is that the boiler only runs when it needs to in order to heat the hot water (or if heating the house) so the only standby losses would be those from the actual tank itself - would you agree or is there something I'm missing here?


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## Slow1 (Aug 1, 2012)

Redbarn said:


> I cannot provide the information that you are requesting.
> I am certainly not going to comb through the minutae of my electric bills to do so.
> 
> I suggest that you contact the manufacturer and get their data. This coupled with some measurements of your usage should get close to answering most of your questions.
> ...


 
Again, I thank you for sharing your experience. 

I apologize for the offense that I have caused, that was not my intention.  I don't expect you to comb through any minutiae on my behalf, however as you had provided some numbers in your posts I was merely trying to extrapolate them to my own situation and having a difficult time understanding the end result.  My apparently incorrect assumption was that since you had been able to report these numbers in the first place that you had a way of retrieving them that you were willing to use.  By pointing out the questions I rather hoped to get you to re-asses them and perhaps help me find the flaw in my assumptions or an error in your reporting.  I am a bit of a 'numbers guy' by nature and thus this is the lens through which I perceive the world and when things appear blurry I find it frustrating.

I have in fact asked the manufacturer for their data and received the generic "it will vary with your installation" answer which although accurate I did not find very useful.


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## Redbarn (Aug 1, 2012)

Woodgeek. I do not know for sure but I agree with you that the reduced AC is probably from the lower standby heat of the boiler.
Our oil boiler seemed to run for 10 mins or so every 2 hours to maintain 80 galls at 100 deg F, no matter what.
So our average DHW temp was likely close to 100 deg F for 24 hours, whatever the usage.
With the Geyser, the temperature varies more so I sure that the average DHW temperature is lower over 24 hours.
That heat difference must show up in the AC usage.

Slow1. No offense taken. I have just never bothered to deeply analyse the numbers.
I just filled the oil tank in April when the oil heater went off and refilled it before turning on the oil boiler for the winter. 
Just calculated oil galls used over the summer. With the Geyser, this was zero.

For the electric bills, I just looked at the averagel kWh over the similar periods and provided they had not changed significantly, was happy.
I had embarked on an extensive insulation program and the number of occupants had changed (daughter went out into the world)
so I had no real basis for accurate comparisons anyway.


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## woodgeek (Aug 1, 2012)

Slow1 said:


> No doubt that when you can get the secondary benefits (retire a dehumidifier) the energy benefits are magnified significantly. I don't currently run one but I don't think it will hurt to pull some moisture out of the air during the summer either.
> 
> As to standby - I do wonder exactly how my oil boiler works. IF the zones don't call for heat I don't ever hear it firing up (I would as it has quite a fan on it to provide draft). Thus although it does kick on periodically, it is generally when we have used some hot water and lowered the temp in the HW tank (not every time though - depends of course on how much HW we use). Occasionally it may kick on to re-heat the tank due to the tank cooling on it's own - but that is not too common. So, my my conclusion is that the boiler only runs when it needs to in order to heat the hot water (or if heating the house) so the only standby losses would be those from the actual tank itself - would you agree or is there something I'm missing here?


 
Interesting. I had a 90s vintage standard oil boiler running a 1.1 gph forced air burner, with a tankless coil. When I bought the house, I was running 1.5 gallons/day, which turned out to be a thermosiphon (which I fixed by closing a manual valve on that zone during the summer). The case on this guy had something like 1/2" fiberglass as a jacket in places, but maybe 40% of the surface had no insulation. I had to run that guy hot (>140°F) b/c of a crppy tempering valve, and I estimated the standby heat loss (DeltaT*Area/R) and got something like a few thousand BTU/h. I also installed a 120V hour timer across the blower motor to measure run hours during standby (when we were out of the house). Anyhoo, even after I stuffed FG insulation all around that case, I was still wasting 0.8 gal/day in standby alone. Measured. Passive losses only out the (insulation upgraded) case. Looking at the boiler specs, it seems that the manufacturers spec the standby loss to be less than a certain percentage (2-3%) of the running BTU output, rather than a low absolute figure, perhaps to just prevent severe overheating of the mechanical room? It can be very hard to estimate standby usage....get an elapsed hour run timer or work backwards from your oil usage - your DHW BTU usage.

To the OP: there is a lot of misinformation re 'heat stealing' by these devices on the internet. Some would have you believe that you could end up spending more net on your heating+DHW bills than if you stayed with a conventional (elec) tank. That is not mathematically possible. Basically half of your DHW BTUs come from elec (all year round), and the other half are either free or negative cost during the summer or cost whatever your space heating BTUs cost during the winter. You will save with one of these in your conditioned space, even in the winter, unless your space heating BTUs cost more than elec BTUs (which seems rather unlikely for a reader of Hearth.com). IF you are using a high-standby oil or propane fired DHW system now, you will make out like a bandit with a HPWH.

And in case I am unclear....I think the geysers are a worthy investment for installs where you already have a tank you like. But you could cost out an all in one also, and maybe assume it would cost $50/year less to operate if you ran it year round.


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## maple1 (Aug 1, 2012)

These Geysers have my interest. I'm in the middle of a boiler changeover (turning out to be a 3 season project) - I've got my new electric hot water tank in place and up & running, and my oil boiler is shut off & has gone cold. I have one of these in mind as a possible add-on upgrade once this project is finished and I have recovered from it. I am thinking that with a couple of installation mods it would be a very efficient unit. My electric tank is bottom entry - I would T the geyser input into that, and T the geyser output into the top to help with stratification & lessen mixing. Then I would duct the geyser air input stream into a vent at the rear of my fridge - that area is always very warm, and it should help with fridge efficiency also. Then the possibility of not having to drag the dehumidifier out & running it anymore, plus added AC effect which could be ducted to the living room really makes things tempting.


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## Redbarn (Aug 1, 2012)

My oil DWH tank is also bottom entry and I  T'd the geyser input into that. I T'd the geyser output into the top and it does seem to help with stratification & lessen mixing. Works well for me.

The benefit of using the cool dry air elsewhere in the house in summer to replace AC is the a real plus.
In the winter however this exhaust air cools the same space that the Geyser draws heat from.
We are fortunate to have a large, fully in-ground basement where the heat flow back from the bedrock was enough to feed the Geyser all winter long.


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## maple1 (Aug 1, 2012)

I guess I'd add that if I did get one, it would be shut down in the winter as we would get all our DHW from the wood fired boiler in heating season - i.e. the Geyser would only be a 3-season unit for us. We only have one small window AC unit that really doesn't help a lot in the real hot days. I have been holding off on adding another one (pretty well ruled it out at this point) on hearing about the Geyser, and also while learning more about mini-splits - I'm kind of wondering what's around the corner for us tech-wise in the next couple years or so.


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## hemlock (Aug 1, 2012)

Thanks for all the great info, everyone.  I've got a few quotes for a unit delivered, and I think I may pull the trigger.  I'm not to concerned about "heat loss", as I heat 99% with wood that is free/cheap.  Electricity in these parts is costly, so I'm quite confident it would be a fairly short pay-back.
One question I do have is this - would it be possible to vent the unit outside to minimize the cooling effect during the winter?  Thanks once again.


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## Slow1 (Aug 1, 2012)

hemlock said:


> - would it be possible to vent the unit outside to minimize the cooling effect during the winter? Thanks once again.


 
While I'm sure anything is possible with a bit of creativity, I am not sure it  would be worth it.  Consider the fact that the air you pump out of the house (venting it out) while cooler than the room temperature is still likely to be warmer than the outside air in the winter.  Then consider that whatever air you pump out of the house will have to come back into the house somewhere (you aren't going to maintain negative pressure after all) so you will be pulling in the same volume of outside air - which will be even colder so the net effect of venting the unit outside may well be to cool the house even more than if you just vent the unit into the home (assuming the temp outside is lower than inside).


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## Redbarn (Aug 1, 2012)

Slow1 said:


> Then consider that whatever air you pump out of the house will have to come back into the house somewhere (you aren't going to maintain negative pressure after all) so you will be pulling in the same volume of outside air - which will be even colder so the net effect of venting the unit outside may well be to cool the house even more than if you just vent the unit into the home (assuming the temp outside is lower than inside).



I agree with Slow1.
I researched and considered this for my installation but reached the same conclusion.


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## GaryGary (Aug 1, 2012)

Hi,
This is just a idle, off the top of the head thought on whats going on in water heating with the HPWH:

1 - The heat pump extracts heat from the house air, cooling  the house air and heating the water in the water tank.
This is not so good in the winter, since, to some degree,  you end up reheating the air that the HPWH cools with your furnace.

2 - The water from the hot water tank goes to a shower.  The water enters the shower head at (say) 100F, it goes does the  drain at 95F taking most of the the heat that the HPWH added to it with it.  That is, you heated the water from 55F up to 100F, then actually used about 10% of it, and sent the rest down the drain.

Isn't there some clever way to use the heat in the drain water to heat the air in the area where the HPWH is operating, so that the HPWH operates more efficiently and does not cause your furnace to come on as much due to the cooling from the HPWH?

Gary


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## Slow1 (Aug 1, 2012)

GaryGary said:


> Isn't there some clever way to use the heat in the drain water to heat the air in the area where the HPWH is operating, so that the HPWH operates more efficiently and does not cause your furnace to come on as much due to the cooling from the HPWH?


 
There are in fact some methods of recovering waste heat going down drains. Most involve coils of copper or other pipe wrapped around the drain pipes which you then run the inbound cold water through before running it into the hot water heating elements/tanks thus pre-warming the cold prior to heating by cooling the waste water. Basically these are water heat exchangers. Not really practical for home use but there is some benefit in settings that have large hot water use - think gym showers or perhaps commercial laundry or other high demand use where you are likely to run the hot water for long periods of time at the same time as you are draining hot water.


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## woodgeek (Aug 2, 2012)

Gary,

The thing to remember (and that you know well) is that compared to space heating, the BTU load we're talking about for DHW is pretty small, and for a HPWH only about half of those BTUs come from the space, with the other half coming from the grid via the compressor work on the refrigerant.

Drain Water Heat Recovery systems (DWHR) are water-water heat exchangers that I guess are getting pretty common in new construction in canada, but are still pretty rare in the US. It also appears that in many places there are code compliance concerns and inspection hassles (due to the threat of mixing gray and potable water streams, I guess). Most importantly, they only recover ~50% of the DHW BTUs, which hurts the payback. With a HPWH, your best DHWR configuration would be to preheat the cold supply stream before it enters the tank, not to heat the space for a comparatively small benefit to COP. I looked at DIY drain water to air exchangers (on paper), but it didn't look good...the peak powers are very high (several kilowatts), requiring a biggish blower, the drain pipes are not very big (requiring something like a massive finned heat sink)....and then it runs <30 min/day. Oh yeah, and the air system would only be used during heating season (but the water one would save year round).

When I looked at this, I decided that going to a HPWH would save me 50% over a conv elec tank (in my mid-atlantic climate), adding a water-water DWHR would get me to 75% savings. But in my case the additional DWHR savings would be ~$100/yr for a family of four and it was hard to get excited about tearing out the finished walls containing my drain pipes, installing a huge, spendy hunk of copper, and cleaning up afterwards. New construction, we could talk.


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## GaryGary (Aug 2, 2012)

Slow1 said:


> There are in fact some methods of recovering waste heat going down drains. Most involve coils of copper or other pipe wrapped around the drain pipes which you then run the inbound cold water through before running it into the hot water heating elements/tanks thus pre-warming the cold prior to heating by cooling the waste water. Basically these are water heat exchangers. Not really practical for home use but there is some benefit in settings that have large hot water use - think gym showers or perhaps commercial laundry or other high demand use where you are likely to run the hot water for long periods of time at the same time as you are draining hot water.


 
Hi,
I'm aware of the GFX style grey water heat recovery devices that preheat the incoming cold water, but I was thinking about something simpler and cheaper that might just heat the air in the general area where the HPWH is.  

As a rough example, in the crawl space half of my house there is an exposed PVC drain pipe from the shower area that runs diagonally across the whole crawl space -- perhaps 40 ft.  I've never measured the temperature drop over its length, but I'd guess its giving back a significant portion of the shower drain water heat to the crawl space (its a conditioned crawl space).

I guess the general thought is that the HPWH will deliver a better COP when it has a warmer heat source, and the heat in the drain water is heat we are just throwing away -- seems like using it for the HPWH would be a win-win -- just need a simple, practical way to do it 

Gary


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## hemlock (Aug 2, 2012)

Slow1 said:


> While I'm sure anything is possible with a bit of creativity, I am not sure it would be worth it. Consider the fact that the air you pump out of the house (venting it out) while cooler than the room temperature is still likely to be warmer than the outside air in the winter. Then consider that whatever air you pump out of the house will have to come back into the house somewhere (you aren't going to maintain negative pressure after all) so you will be pulling in the same volume of outside air - which will be even colder so the net effect of venting the unit outside may well be to cool the house even more than if you just vent the unit into the home (assuming the temp outside is lower than inside).


 
I'd considered that.  My solution for "make up air" to compensate for the air that would be pumped outside would be to remove the exhaust air duct from the heat recovery ventilator that shares the same room as the Geyser, thus the Geyser would then act as the exhaust.  Hopefully, this would somewhat balance out any negative pressure situation that would otherwise occur.


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## Slow1 (Aug 2, 2012)

hemlock said:


> I'd considered that. My solution for "make up air" to compensate for the air that would be pumped outside would be to remove the exhaust air duct from the heat recovery ventilator that shares the same room as the Geyser, thus the Geyser would then act as the exhaust. Hopefully, this would somewhat balance out any negative pressure situation that would otherwise occur.


 
Solves the negative pressure all well and good.  However, then consider that the HRV (assuming you keep it running) is now wasting power pumping the cold air into the house - same problem, you are cooling that room with cold air.  The HRV is essentially a heat exchanger - it helps to ventilate the room with fresh air without affecting the temperature (much) by heating the inbound air with the warmth from the air it blows out - thus the exhaust is colder than the room air.  If you disconnect the exhaust and blow it into the room you will be blowing this colder air into your room.  The 'wasted power' I'm referencing of course is the fan blowing for no real purpose - let the negative pressure draw the cold air in itself if you are going to have it come in anyway.


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## DBoon (Aug 3, 2012)

Hi Slow1,

I have a Geyser HPWH.  I bought it for about $1100 delivered to my house direct from the company that makes them.  I wouldn't pay more.

I have had it for a little more than a full heating season.  I live in a cold climate in upstate NYU with a well-insulated basement, and desired to lower my (already low) electricity usage for hot water direct electric heating and provide some dehumidification for my basement.  It has worked well on both counts with some caveats.

First, I have a day/night electric meter and ran my hot water direct electric tank on a night timer and used approximately 220 kWh/month for water heating in the winter, 170 kWh/month in the summer and about 200 kWh/month in spring/fall.  My HPWH is on a 115V circuit and I have metered it with a Kill-a-Watt meter and I have the following data to report:

Summer 2011 - 85 kWh/month
Fall 2011 - 110 to 120 kWh/month
Winter 2011/12 - 200 kWh/month (this led to a lot of changes, discussed below)
Spring 2012 - 150 kWh/month (colder incoming water than fall?  Also, I made changes, discussed below)
Summer 2012 - 60 kWh/month

First, I tried to run the HPWH like my direct electric heater with a night timer and storage throughout the day.  I heated the water to 130 degrees F overnight and used it during the day.  Worked well that first summer.  However, this didn't work in the winter - 8 hours wasn't enough time to heat the tank. 

So, in Winter 2011/12, I let it run whenever it needed to, and it was running a lot.  By the end of the winter, my basement was 50 degrees F and the COP seems to really go down at that temperature.  I put an electric resistance element on backup and was still using a lot of energy for the HPWH and it was running a lot.

In Spring 2012, the performance didn't improve as much as I thought it should have by May 2012.  I think that it was partly because the basement was a good 5 degrees colder than the previous May (HPWH had done that).  I also worried that I had some scale in my heat exchanger (I have since installed a water softener).  So, I reduced the temperature to 120 degrees in the HPWH from 130 degrees.  That helped a lot.  Also, I had noticed that my wife would run straight hot water when rinsing dishes - using the same hot water at slightly lower temperatures reduced the usage a bit as well.

In Summer 2012, I started out by getting about 110 kWh/month usage.  I think this was because of the colder basement.  Also, I noticed that the insulation on my outlet pipes was not what it could be.  I did a better job of thoroughly insulating all of my pipes, and double insulated the pipes between my tank and the HPWH and my usage dropped to 60 kWh/month.

The bottom line for me is the following:


You will probably find that in the northeast, the basement will get too cool in deep winter with this thing running, and you will want a backup heating plan for the hot water.
My unit runs about 6 hours a day in the summer, and 12-15 hours a day in the winter, and we don't use a lot of hot water compared to most people.  If you have a large family, I don't see it supplying all of your need in the winter - you will need a backup element (even I did last winter, but maybe not this coming winter due to extra insulation and settings changes).
You will get a fantastic dehumidification side-benefit from this - that was actually the main reason I installed it.  I was tired of running a dehumidifier in the basement 8 hours a day in the summer with all of the attendant costs and heat generation. 
Plan on using it at 120 degrees F (the factory setting).  The HPWH seems lose a lot of COP/efficiency in going from 120 degree water to 130 degree water.
You must be meticulous in insulating all of the pipes coming out of the hot water heater, and if you don't have great insulation on your tank, insulate that with more.  Don't setting for the single layer of insulation on the hoses connected the HPWH to the tank.  Double-insulate thos with more insulation.  Don't allow one bit of exposed pipe surface anywhere - tape everything up thoroughly to ensure it stays in place. 
PM me if you have any specific questions.  FYI - I am only checking this site about once/week, so a reply could take that long.


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## Ehouse (Aug 3, 2012)

I Think drawing the heat from your septic tank (if you have one) is an idea worth exploring.  Start with a simple DX fan coil set up and an insulated tank.  Before you pounce, I said explore.  I'm aware that the powers that be will shriek in outrage, but if you think about it the potential problems don't seem insurmountable.

Ehouse


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## Slow1 (Aug 3, 2012)

Thank you DBoon - I really appreciate the detailed write up.  I don't have the humidity in my basement - likely due to it being half exposed (on a hill so we have a walk-out the back).  The other down side is that it is already colder in winter so less heat to draw on - likely get the feeling I'll have to either turn off the DWHP in winter or provide heat to the basement in another form which has been under consideration but makes for an odd way to heat the water eh?


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## maple1 (Aug 3, 2012)

DBoon, are you able to quantify or estimate the electricity savings realized from reduced dehumidifer operation?


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## DBoon (Aug 3, 2012)

Hi Slow1 - you may have more humidity than you realize.  Just about any below ground area - even partially below ground - will have overall high humidity levels in the summer.  I would be very surprised if your humidity is below 60% in the summertime.  

Hi Maple 1 - I used to run a dehumidifier 8 hours a day (overnight) for about 5 months a year.  The dehumidifier rating is 115V @ 5.4A = 621 watts/hour.  For 8 hours, power consumption would be 4968 Watts - let's round it off to 5 kWh per day.  For 30 days, that is 150 kWh/month, or over 750 kWh a year.  My night rate (I ran the dehumidifier only overnight) was 11 cents/hour, so the cost per year was $82.50.   This might be low - my wife would often run it more - not because it needed it, but because she was sensitive to mold and worried that I wasn't running it enough.  

Now, I will admit that this certainly helps with the payback of the HPWH.  I figured that (overall) I would save ~100 kWh/month using the HPWH versus electric resistance heat, or 1200 kWh/year.  Add that to the 750 kWh/year by not running the dehumidifier, and I would be at a 1950 kWh/year savings - lets round that up to 2000 kWh/year at 11 cents/kWh and that is $220/year in savings, or a 5 year simple payback on the HPWH (6 years counting installation). 

I'm not sure that I'll get this savings - given my earlier post, I'm not sure that I'll really see 1200 kWh/year in savings.  I think it is likely to only be about 800 kWh/year due to wintertime inefficiency.  Electric rates have also gone down a bit - especially in the non-peak electric season (anytime but summer), so 11 cents/kWh is probably a little high, overall.  But, I'm an efficiency nut always trying to reduce my usage, and I get a nicely dehumidified basement year round that never smells musty.  Knowing what I know now, I would still buy the Geyser again.


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## begreen (Aug 5, 2012)

What is the repair history on these units? In order to get the expected ROI are they expected to be repair free for 10-12 years?


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## Redbarn (Aug 5, 2012)

There was a long thread on Heat pump water heaters in 2009. Reads a bit dated now but some usefull data there.

https://www.hearth.com/talk/threads/heat-your-water-with-a-heat-pump-50-electric-savings.30309/


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## begreen (Aug 6, 2012)

Thanks for the back link. I checked into a HP for hot water for our house but was discouraged with the repair record for the all in one units. That's why I asked how the Geyser's track record has been.

Our electricity is a bit cheaper and we use less hot water than average. The extends the payback period for us.


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## Redbarn (Aug 6, 2012)

begreen said:


> Thanks for the back link. I checked into a HP for hot water for our house but was discouraged with the repair record for the all in one units. That's why I asked how the Geyser's track record has been.
> 
> Our electricity is a bit cheaper and we use less hot water than average. The extends the payback period for us.


 
The person with a lot of history with the Geyser and its predecessors is Tom in Maine.

He installed Geyser ancestors called Nyletherm.
He is a Geyser dealer so may not be unbiased but could give some history.

We have owned ours for 15 months so cannot really comment.


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## tom in maine (Aug 17, 2012)

I don't usually check this forum, but just came across this thread.
I have had my hands on a lot of Geysers and their predecessors, the Nyletherm.
Also know the principals in the company from way before they started making these units.

Don Lewis, who is the chief engineer, is an extremely conservative engineer, who prides himself in making dependable, durable products.
That being said,the units are pretty solidly built. The latest changes they have made are upgrades in the controls and a slight efficiency bump.

The current controls are hand wired and use contactors and time delays that are all readily available online and from Grainger.
The controls used to be potted in epoxy which were decent but not serviceable. 

What separates these units from the all in one units is the fact that they can be swapped out from one tank to another in case there is a tank leak.
All in one units cannot be re-used. They use a copper coil that is wrapped around the outside of the tank.

Here in Maine, our electric cost is 18 cent a kwhr. In my household, we use about $20 a month to operate the Geyser. This has been consistent
for several years. We use a fair bit of hot water daily.

There are downsides. My home unit is only operated from May through October. My basement is small and insulated with spray foam, so the unit tends to steal energy from the first floor of the house. This is great in the summer. It gets to be less fun in the late Autumn.

The recovery is 1/2 that of an electric water heater. This could be annoying. I heat a 350g tank that we sell. We do not run out of hot water.
A 40 gallon tank can be tolerable and manageable. If you have a teenager and can beat them to the shower, you are guaranteed to not have them in for too long.

We offer these as the preferred backup to our new solar DHW system.

As someone mentioned, we do sell them. That could make me biased. I am biased in that they are made here in Maine, but I would not sell them if I did not
think they were a good investment.

My long 2 cent worth!


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## hemlock (Aug 27, 2012)

Bought a Geyser, and it arrived today (a big thanks to Tom in Maine).  Hopefully, I'll have it hooked up in a day or so.  I do have a question however - it says to use Pex and crimp fittings, but would "Sharkbite" fittings be acceptable with the Pex?  I don't have the crimping tool for the traditional Pex pipe installation.

As an aside - thanks for all of the responses.  It helped in making my final decision.  I'll be anxious to see my next few power bills after the install.


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## tom in maine (Aug 27, 2012)

Sharkbites are fine. Nyle just assumes that everyone would want to use crimp connectors!
I am actually amazed that so many people have access to crimp tools.


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