# tankless electric water heater any thoughts??



## petemal (Jan 26, 2012)

not sure if this is the forum but i know there is a lot of knowledge out there.  I am trying to rid myself of oil as much as possible,  4.00 a gallon and going up fast,    last year i installed an insert Austroflamm/Rika integra II in my den,  lowered my fuel consumption from 1000 gallons year to about 400.  2650 sq ft above ground living space 2 story. I am currently using hydonic and radiant heat as a back up to insert.  Heat is not the problem,  My boiler is about 5 years old I heat my hot water with oil,   indirect from boiler,  i currently have a turbomax 2000 Instantaneous Indirect Water Heater.  There is no gas in the street and about 6 houses down,  the local company wants to much to install it,  I feel that my boiler is always running to keep my hot water at the temp.  even though i am not using it for heat.  i looked into these tankless heaters a few years back and installed one in office but it only seemed like the hot water lasted for a few mins   not enough for a shower,  I just spoke to a friend and he installed one of these and he said they are great,  here is the link

http://www.wamhomecenter.com/produc...ter-Heater-Point-of-Use-5-GPM-1165p121125.htm

it is suppose to handle 5 gallons a min much more then the ones before,   i guess the question is 
Does anyone have experience with these units? 
is it worth it?
should i get rid of my hot water system entirely or use with it?
will this really handle my house?
how much was the electric bill increase?
can anyone recommend a unit or brand for entire house?


I currently have a 10.8kw PV system so i looked into solar hot water but it doesnt seem practical,  I use most of hot water in early morning or late night when the sun is not out,  even with the storage tanks i feel i will loose temp.
I have one solar tube and several skylights, i feel this is the final step to being completely efficient.  My goal is to bring down my oil use to 80 gallons a year.   and i could focus my efforts on my pellet storage...   any suggestions


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## vinny11950 (Jan 26, 2012)

This will probably get moved to DIY forum.

Can't speak for the Rheem, but I replaced my old water heater with a Steibel Eltron electric water heater.  Made in Germany

http://www.amazon.com/Stiebel-Eltro...NRY2/ref=sr_1_1?ie=UTF8&qid=1327618296&sr=8-1

Works pretty well.  I should add, the first one stopped working after a month.  Some type of computer chip problem tripping the safety switch.  Anyway, they sent a new one right away at no cost.  However I did have to pay the plumber another $100 to switch.  But since then, it has been good.

The big expense was running the super copper wires for the voltage, and the minor plumbing to rework the pipes to fit the unit.

The water is warmed to desired temp, and there have been no spikes or drops in temp.  Even in the coldest days, it can handle it.  Sometimes the hot water pressure is low, but I am sure that has to do with the neighborhood water pressure, which fluctuates sometimes.

In a regular month, when not using the pellet stove, my electric bill is around $120.  Two people, three bedroom ranch.

Hope this helps.


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## Cooper (Jan 26, 2012)

Im in your boat i have tankless water heater oil boiler and im looking to get off the oil!
The only problem i have with electric tankless is the amps at 75!  normal 20 amp breaker wont cover the load im thinking 40 gallon electric water heater


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## Enigma869 (Jan 26, 2012)

The post is interesting to me, because I've never seen a tankless hot water heater that worked with oil.  I had a Rinnai in my last house but that was on propane.  I've always been told that tankless hot water heaters only work with natural gas or propane.


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## Cooper (Jan 26, 2012)

The tankless these guys are showing are electric powered not oil .


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## Enigma869 (Jan 26, 2012)

Cooper said:
			
		

> The tankless these guys are showing are electric powered not oil .



Got it.  I guess I didn't even know that was possible.  I love this place.  Quite the education.


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## imacman (Jan 26, 2012)

You might want to post this (or one of the mods will move it) in the " DIY and General non-hearth advice" forum.


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## 1Dtml (Jan 26, 2012)

I'm a bit perplexed on why your indirect hot water tank is running your boiler all the time, for my new install runs only when water is in use.

I went the other way to complete my end of oil dependance in that I had the tankless coil removed from my oil boiler, and had a top performer indirect tank installed.

http://www.vaughncorp.com/html/tp.html

The top performer doesn't lose more than 2* in eight hours, and now that my boiler isn't firing all the time (as it was with a tankless coil set up) even though the basement is below 50* during the winter.

You may need to see if your oil boiler is set to "cold fire," which means it only fires when a zone calls (the indirect tank is basically a zone), so that the boiler isn't firing all the time to keep the temperature high enough to heat water all the time (as with a tankless coil set up), only when the zone calls. The low limit on the oil boiler is set low on a cold fire set up as to not waste oil.

I love this set up combined with the pellet stove, and would recommend it over tankless systems.

The installer said the "top performer" has a stone/cement liner that keep the heat in, and believe me there is more heat loss in my piping (I'm going to insulate them better) than this tank loses, for as I've said it doesn't tend to run unless we are using large amounts of hot water.

I was going to add a solar hot water system, but now with this set up it isn't worth it for I'm barely using any oil.

Good luck,

1D


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## Brewer (Jan 27, 2012)

My hot water heater died 2 wks ago, it was a 1993 lowes deluxe 40 gal self cleaning with 8 yr warranty........thought seriously about the tankless electric....about $1500 for one that might have been borderline adequate, got to the part about the electric upgrade that Cooper mentioned....another few hundred bucks....found out that if your water is the least bit hard it plays he'll with them,our water Is extremely hard, went with the basic lowes 6 yr 40gal......$219 and some change


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## petemal (Jan 27, 2012)

[quote author="1Dtml" date="1327639988"]I'm a bit perplexed on why your indirect hot water tank is running your boiler all the time, for my new install runs only when water is in use.

I went the other way to complete my end of oil dependance in that I had the tankless coil removed from my oil boiler, and had a top performer indirect tank installed.

http://www.vaughncorp.com/html/tp.html

The top performer doesn't lose more than 2* in eight hours, and now that my boiler isn't firing all the time (as it was with a tankless coil set up) even though the basement is below 50* during the winter.

You may need to see if your oil boiler is set to "cold fire," which means it only fires when a zone calls (the indirect tank is basically a zone), so that the boiler isn't firing all the time to keep the temperature high enough to heat water all the time (as with a tankless coil set up), only when the zone calls. The low limit on the oil boiler is set low on a cold fire set up as to not waste oil.

I love this set up combined with the pellet stove, and would recommend it over tankless systems.

The installer said the "top performer" has a stone/cement liner that keep the heat in, and believe me there is more heat loss in my piping (I'm going to insulate them better) than this tank loses, for as I've said it doesn't tend to run unless we are using large amounts of hot water.

I was going to add a solar hot water system, but now with this set up it isn't worth it for I'm barely using any oil.

Good luck,


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doesnt the boiler need to run to dump hot water in the tank to store it there so when i call for hot water it is there. even if it calls for hot water 3x a day can i cut that down,   also i will check on the cold fire   where will that be on the aquastat


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## krooser (Jan 27, 2012)

I had a NG tankless installed two years ago. Really don't notice much difference in the gas bill or water usage to be honest... but it sure was a pricey little deal!


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## hoverfly (Jan 27, 2012)

Thankless hot water heaters are for low flow water savers, in foreign countries like in Europe or California. You might be able to install boosters at the sink, shower or tub to help with duration, essentially another thankless. But the barker box might need to be upgraded to handle all those amps needed. Also such a system may cost the same as some of the more expansive alternatives. There are thankless boilers that most likely meet a typical American demand, some are built to handle hard water, but cost a lot more. At this point might as well look in to spending into a $5,000 to $7,000 solar domestic hw with a propane or oil fired hw tank. Then there is just suck it up. 

Right now my wife and I are looking into a new manufactured home, so l am looking at best options working in with a pellet stove as a long term investment. But a pellet boiler is not happening.


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## petemal (Jan 27, 2012)

why is a pellet  boiler not a good option


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## 1Dtml (Jan 27, 2012)

petemal said:
			
		

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## smoke show (Jan 27, 2012)

Hoverfly said:
			
		

> *Thankless* hot water heaters are for low flow water savers, in *foreign countries* like in Europe or *California*.



 :wow:


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## petemal (Jan 27, 2012)

1Dtml said:
			
		

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## seige101 (Jan 27, 2012)

petemal said:
			
		

> I currently have a 10.8kw PV system so i looked into solar hot water but it doesnt seem practical,  I use most of hot water in early morning or late night when the sun is not out,  even with the storage tanks i feel i will loose temp.
> I have one solar tube and several skylights, i feel this is the final step to being completely efficient.  My goal is to bring down my oil use to 80 gallons a year.   and i could focus my efforts on my pellet storage...   any suggestions




We had Solar hot water for 12 years when the house was first built. We had more than enough hot water in the morning for showers and late at night when the dish washer or washer would run. It was an 80 gallon tank heated to 135* with a regulator set for approx 118*. The only reason we don't use the system is after the tank failed after 12 years because of our horrible well water my grandfather did not want to pay the approx $1000 to replace it instead opting for $200 electric. When the new roof was put on 5 years ago he had the solar panels removed. 2 of the stupidest decisions regarding maintenance of this house =(

This was using 1982 technology. We would have to run the hot water during the day or the tank would over heat.

It would produce decent hot water even on pretty cloudy day and had a 115volt element to serve as a backup.

Something to look into, i am will be looking into it after other items are upgraded in the house.


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## drizler (Jan 27, 2012)

It's gonna cost you a pile of cash to do all the wiring and installation to save a few cents.   My indirect oil fired tank bit the dust last winter and good riddance.   I went to Lowes and bought a simple 40 gallon electric.   The whole rig cost me under 300 bucks and works fine.   To make it better I mounted it upstairs in a nice warm closet.     The best part is that going to electric hot water upped my bill about 25 bucks a month.   Thats Nothing copated to getting ***** for oil.   The best part is I have NYSEG which is one of the highest.    Aside from the pellet stove I heat the rest of the place with a few electric space heaters and it's still far cheaper than oil.   
  The folks selling this stuff have spent a lot of money pushing their complicated, issue prone water heaters.   Personally I think there is more pitchmanship going on with those than substance.    For most people a simple reliable tank mounted in a warm place with a decent blanket on it is still the better deal and all it costs you is a dedicated circuit and some 10 gauge wire(which will still knock you over if you need a lot of it).


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## 1Dtml (Jan 27, 2012)

Pete,
My response was based on your comment that your "indirect hot water tank was firing all the time."

Any system will have to activate when when the hot water is used, but with my set up the hot water tank holds temperature for well over eight hours, so it keeps the boiler from firing.

I would check to see if is a "cold fired" set up either directly with a oil technician or ask for specifics on one of the many forums that are available on the net.

Having said this, I believe if set up properly your current indirect hot water tank should be very close to as efficient as any option available, while providing enough hot water availability.

Heat loss will be the enemy with any system, so if your hot water tank doesn't hold the heat well you should look to purchase and install an insulating kit for it, and then make sure that your hot water lines are insulated as well.

I hope this helps,

1D


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## BradH70 (Jan 27, 2012)

When we had our house built 9 years ago I opted to have the contractor install a Amtrol BoilerMate instead of a crappy 8 x 16 deck. We used ~250 gallons of oil over the past year to heat our DHW. I have crunched the numbers many time to try and figure out if an electric water tank would be cheaper and it works out that the electric tank would be more expensive to run at current prices for oil and electric. Oil is $3.70/gallon and electric is $0.0155/kW. The only problem is that my calculation don't take into account the inefficiencies of the oil boiler. An electric tank would not have some of the inefficiencies of the indirect tank that the BiolerMate has.

http://www.amtrol.com/boilermate.html

Here is a post from a previous thread (https://www.hearth.com/econtent/index.php/forums/viewthread/87657/):

1 gallon of oil = 115,000 BTUâ€™s x 250 gallons = 28,750,000 BTUâ€™s
1 kWh of electricity = 3,413 BTUâ€™s

Soâ€¦. 28,750,000/3,413 = 8,423.67kWh * $0.155 = $1,305.67

From kofkorn:
There are a few things wrong with this, mostly not related to the calculation, but related to design and efficiency.  You didnâ€™t consider your efficiency of the oil burner which is likely somewhere around 80-85%.  That means that 15-20% of your heat is going directly up the chimney.  Additionally there is a significant loss when you go from the furnace to the Boiler mate, as the heat can only transfer so quickly.  Add onto that, the heat loss of the furnace to your room due to insulation, plus the heat loss of the boiler mate to the room.  Also add in the cost of electricity to run the circulator to keep the Boiler mate heated. 

Now on the other side, electric resistance heaters are 100% efficient.  Subtract from that the energy lost to the room due to insulation. 

Now compare the two.  There likely wonâ€™t be a huge difference between the two.  I think you will see the biggest difference between the insulation heat loss between the furnace and the electric heater.  Iâ€™ve found very few situations where an electric hot water heater is better in the winter, when the oil is also being used at the same time for heat.  However, if you are keeping the furnace running for DHW only, you will almost always find that the electric is cheaper.


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## kinsmanstoves (Jan 27, 2012)

The electric ones do use a lot of juice and I do not have 200 amp service.  I have a propane tankless mounted above my toilet in the main bath.  It does the shower, bath sink, kitchen sink, and dish washer.  Awesome unit and going on 5 years old.  I also found the exact same unit that was only used for 125 gallons before they removed it.  I bought it for cheeeeeap so I have a back up.

Eric


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## 1Dtml (Jan 27, 2012)

I'm all about efficiency of systems, but I didn't try to replace my current system (oil boiler) with a solid fuel system like a pellet boiler, I chose to use pellet stoves for heating, and keep my oil burner as back up (if something happens I'll still have hot water, and heat).

The tankless coil oil boiler set up was firing all the time to keep the boiler at temperature for instant hot water, so I switched over to an indirect storage tank which allows the oil boiler to be "cold fired" when any zone calls including the indirect storage tank, while the storage tank keeps 50 gallons of hot water waiting for instant use.

My intention was to add a solar domestic hot water storage tank system in the future, so I added some additional temperature gauges to the indirect oil fired storage tank to monitor the two systems. I purchased one of the most efficient indirect water storage tanks that was available http://www.vaughncorp.com/html/tp.html , and have been amazed at how little heat loss there is without the boiler firing to add hot water to it.  I am able to monitor how efficient this storage tank is by looking at the extra temperature gauge that is installed above the tank on the hot water feed to the system. The temperature of the aquastat on the storage tank is set at 140*F, and holds this temperature without calling the boiler for well over 12 hours in a basement temperature of 40-50*F.

This is amazing considering that I still have to insulate all the hot water piping.

I had figured a 6 year payback if I installed a solar hot water system, but with this change I'm not going to bother because my oil usage has dropped so low that it isn't worth it.

I consider investment as a total package, and how quickly a given investment pays for itself, so I would highly recommend adding insulation to what you have before changing the system, for some are saying that electric is about the same cost annually, so why spend the $$ on plumbing changes and different equipment, if what you have is in good working condition?????

1D


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## md2002 (Jan 27, 2012)

I don't know about electric but I bought a house recently with Oil fired tank-less hot water heaters and we never had enough water. The hot water would never be enough to take a full hot shower. We just installed a indirect water tank this week and couldn't be happier. We could have replaced the coil but the plumber said we would be doing that every 5-6 years. Also, if you live an an area that has bad water it will kill those systems and they wont last as long as they should.


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## krooser (Jan 27, 2012)

My system will allow you to shower, use the dishwasher and the washing machine at one time. There IS a slight lag (maybe 30 seconds or so when the water temp will fall if you are showering and the other two appliances call for water)... that does not happen much in our house.


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## subsailor (Jan 27, 2012)

I shut my furnace down, which was the source of my hot water. I replaced it with an electric hot water heater. My electric bill only went up $25/month and we have some of the highest electric rates in the country!


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## petemal (Jan 28, 2012)

krooser said:
			
		

> My system will allow you to shower, use the dishwasher and the washing machine at one time. There IS a slight lag (maybe 30 seconds or so when the water temp will fall if you are showering and the other two appliances call for water)... that does not happen much in our house.






IS THAT A TANKLESS SYSTEM    what brand and type


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## hoverfly (Jan 28, 2012)

petemal said:
			
		

> why is a pellet boiler not a good option



To heavy, I don't think the weight could be supported, but I could be wrong. It's also one of the more expensive options, leaving out a back up options like propane heat and hot water and a back up generator.


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## Dr.Faustus (Jan 28, 2012)

a few years back i was considering all this as well. I was looking into either a propane or electric tankless water heater. after doing a lot of research, i came to the conclusion that the unit is pricey, it will suck up a lot of electric and i'll never see payback, and with propane i might have eventually seen payback *if* the unit held up against my extremely hard and 900ppm TDS well water.

so went with the 40 gallon middle of the road standard tank from home depot. it raised the bill 25 to 30 a month for electric, sometimes less but not more than that. we use cold water to wash clothes. the dishwasher uses hot water but i dont think it uses a lot of it.

we never run out of hot water even back to back showers. may only run out if wife fills the jacuzzi tub with hot water but recovers in 10 15 minutes.

i think i made the right decision. i'm happy and oil-free.


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## ablejoy (Jan 28, 2012)

I bought one of those pricey tankless water heaters last year mine is propane. The wife has a spa tub and now never runs out of hot water. Hope it holds up I put the water softener on the hot water side before the softener. So far so good


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## krooser (Jan 28, 2012)

petemal said:
			
		

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Yep... it's sorta the middle capacity one I think...maybe an American Standard or Rheem? I'll check tomorrow on the brand...can't remember.


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## Pellet-King (Jan 28, 2012)

For the money you spend on a tankless you can buy 3 tank models, the energy use is close to being the same, I'm cheap and do whatever is the cheapest way, why i burn pellets


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## rickwai (Jan 28, 2012)

I have a propane standard 40 gal water heater. My wife and I and a 11 yr old daughter. We rarely run out of HW. Occasionally if the girls go first I will get shorted. It does recover quickly. The tankless units have way to many controls for me. To much potential for breakdown, and when you opoen the front and see the circuits boards ect. it just screams high repair cost. I just cant see the advantage unless you have a high demand and dont have room for a large hw tank.


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## 1Dtml (Jan 28, 2012)

For those that have corrosive and or hard water problems this condition effects all plumbing hardware not only oil fired, and needs to be corrected to stop its effects.

1D


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## hoverfly (Jan 28, 2012)

Pellet-King said:
			
		

> For the money you spend on a tankless you can buy 3 tank models, the energy use is close to being the same, I'm cheap and do whatever is the cheapest way, why i burn pellets



Though the tanks are insulated better than in the past, you still pay for the additional heat loss in storing such a large mass. Therefore your savings in a thankless is not having to store the water.


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## 76brian (Jan 28, 2012)

smoke show said:
			
		

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I lol'd at that part.

I don't know if it was supposed to be funny, but i still found it funny.


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## Fish On (Jan 29, 2012)

well funny how this subject came up, walking into the basement after work and wow my hot water heater was leaking. were lucky that this winter sucks for snow because we would be riding right now, talk about a major flood when when we did come home.  so quick wet vac cranking and a major disaster adverted. 

total bummer I got 15 years out of it and now I'm wondering if i should just install an electric.

if gas was an option i would do a tank less.


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## petemal (Jan 29, 2012)

Fish On said:
			
		

> well funny how this subject came up, walking into the basement after work and wow my hot water heater was leaking. were lucky that this winter sucks for snow because we would be riding right now, talk about a major flood when when we did come home.  so quick wet vac cranking and a major disaster adverted.
> 
> total bummer I got 15 years out of it and now I'm wondering if i should just install an electric.
> 
> if gas was an option i would do a tank less.




sorry for the loss    but 15 uears aint bad   look at the rheem rte 18  i think its instant electric   people have been saying some goods things about it


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## Fish On (Jan 29, 2012)

That would be an option but I think it would be not enough to keep up in my house, Plus the cost for me to run the wire and it needs 75 amp I think, got plenty of room because I rewired my whole house and panel.

So I will more then likely go with oil like I had, just sucks because natural gas is just not in my area and I would go nuts looking at a propane tank outside.


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## rkshed (Jan 29, 2012)

I looked at tankless last year and a common theme was that they are not the best in colder climates. I could never find out for sure why, but a $300 electric tank was a safer bet for me.


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## krooser (Jan 29, 2012)

This spring I want to hook up a hot water line to a new outside water bib so i can have hot water for my pressure washer....


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## Krik (Jan 29, 2012)

rkshed said:
			
		

> I looked at tankless last year and a common theme was that they are not the best in colder climates.



Because most of the time the cold water coming into the house is a lot colder than in warmer climates, and the tankless needs to put more energy into heating it to a specific temp at the same flow rate. It's the same issue as with geothermal heating. The mid-winter 6 ft deep soil temperature difference between Maine and Florida, for example, is easily 25F, and the tankless will have to put in at least 25% extra heating power to get it to 120F (which is a substantially larger tankless and electric requirements).

Another option is to use a heat pump hot water heater. Normally these also suck in cold climates, because they work by extracting heat from the air. So your precious heating dollars are wasted, or your basement is simply too cold to make the heat pump work and the thing reverts to resistance heating. BUT, if you have a wood or pellet stove in the basement and keep it relatively warm (60F or so), you might come out ahead. I'll compare tank to tank, so we can leave out standby loss for a minute.

In my conservative estimates, I'll say the heat pump has a cop of 2.25 - that is, for every KW of electric you put in, it pulls 1.25 KW of heat out of the air to heat the water with 2.25 KW. Also, I'll assume the pellet stove is a measly 70% efficient. In my world, with $0.15 per KW electric and $275 per ton of pellets, this means that a $1 electric heating unit is the same as $0.56 pellet heating unit. So if I spend $2.25 for 100% electric, I'd spend $1.70 for heat pump, which is roughly 25% savings. If you heat with cheap $199/ton pellets it's $1.50 for the heat pump,  which is 33% less. Don't think a tankless can easily beat that unless your hot water usage is really low (and the price of the two should be very similar).

The number one requirement is that the space with the water heater is heated by wood/pellet stove air and that it stays relatively warm. A big if, but I think it might just work for some folks on the forum.


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## hoverfly (Jan 29, 2012)

krooser said:
			
		

> This spring I want to hook up a hot water line to a new outside water bib so i can have hot water for my pressure washer....



Nice!!


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## fadippides (Jan 29, 2012)

Here is an article (mostly discusses gas tankless)

http://www.askthebuilder.com/451_Tankless_Water_Heaters.shtml


When you think of a tankless electric vs an electric tank, both are 100% efficent (more or less).  Tank models today do not lose a lot on standby.

There is another option though a heat pump electric water heater

http://www.google.com/products/cata...l4lT4GvF8bu0gHEx8ztCA&sqi=2&ved=0CJMBEPMCMAI#


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## hoverfly (Jan 29, 2012)

Krik said:
			
		

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I forgot about those new hw heat pumps.


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## hoverfly (Jan 29, 2012)

fadippides said:
			
		

> Here is an article (mostly discusses gas tankless)
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Well I guess the tank less hw just got "tanked". If you use a tank-less boiler for both heat and hw with an indirect that would work just fine.  If not a the best option if you still need back up heat and lets face it everbody loves unlimited supply of hot water.


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## woodgeek (Jan 29, 2012)

Lots of good info on this thread....I've looked at this a bit, and it seems clear that for gas/propane, the flue losses are so high in a tank system that a tankless system saves you 30% in operating cost over a tank.  Whether you make back the higher cost of the tankless depends on your fuel cost.  

BUT, in an electric tank, the losses are so low (<15%) that the it is really hard to see how you can make back the upfront cost on a tankless electric (and 75A wiring).  For that kind of money you could get a HP tank unit (even if you only ran it in HP mode during the warm season) and come out way ahead after a few years.  IMO, the electric tankless make the most sense in special applications, like add on bathrooms a mile from the boiler, apts without anyplace to stick a tank, etc.

To the OP with the indirect...if the boiler is cold start, your standby usage should be really low if the setup is properly installed/insulated.  At the current price of oil and elec, the cost per BTU is close, so if the standby can be eliminated, you can just use the hardware you have...


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## Retired Guy (Jan 31, 2012)

Before installing an electric tankless on demand water heater, I would seriously consider a Marathon.  If I didn't have NG that's what I would do.


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