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Hybrid electric water heaters

Started by samandothers, February 15, 2020, 09:38:40 AM

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samandothers

Anyone have one or have some knowledge related to these.  I was recently researching water heaters for a new home installation and ran across these units.  Seems they have a heat pump in addition to some heating elements.  The energy usage on the energy guide seems to be about a third of an electric water heater.  Price is about 3 times the cost also. 

If reliable The payback seems to be short enough to make it an attractive option.  

WV Sawmiller

Sam,

   What is their capacity? Does it just heat the water as it passes through the line? If so how warm will it get the water? I have used on-demand hot water heaters in some places and they did okay but I don't know how well they could keep up with household needs of several showers, a dishwasher and washing machine in a house full of people. We had a regular electric water heater at a home in NC when I was in USMC and we had to schedule showers as it could not recover fast enough. I love my gas heater here.
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samandothers

There are different gallon sizes.  I was lookng at 50 gallon.   The unit has a heat pump that uses basement or crawl space air to heat coils that wrap around the tank.  There are supplemental electric elements during high demand.  

The limit appears to be 120 degrees.  That would be a problem for a dish washer unless it has a built in heater.

EOTE

Quote from: samandothers on February 15, 2020, 09:38:40 AM
Anyone have one or have some knowledge related to these.  I was recently researching water heaters for a new home installation and ran across these units.  Seems they have a heat pump in addition to some heating elements.  The energy usage on the energy guide seems to be about a third of an electric water heater.  Price is about 3 times the cost also.

If reliable The payback seems to be short enough to make it an attractive option.  
Consider instant water heaters.  They are tankless, they provide instant heat and are economical.  I installed an electric instant heater for my bathroom and we don't actually use a lot of electricity because it doesn't have to heat a lot of water or keep a large tank of water hot.  I've never run out of hot water with it.  For a shower and 2 sinks it doesn't cost more than about $10 a month.  They have gas fired ones but I chose electric because we are semi-off-grid. 


 
EOTE (End of the Earth - i.e. last place on the road in the middle of nowhere)  Retired.  Old guys rule!
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Al_Smith

My lady fair had a heat pump type water heater which seemed to work well .Supposedly it saves on power usage .It had a micro processor  controller on it that could be programmed for time off in the case of going on vacation,temperature  etc .It certainly was not cheap .Weather it would  be worth the extra money or not would be up to whoever bought it .
In my case I get about 8 years out of a water heater so the extra money wouldn't do me much good .Hard water you know ,mineral content etc .I'd be throwing money away and I'm a tight wad ,not for me .
Rambling on when I buy a replacement water heater I go with high recovery ,mid priced unit and it works for me .40 gallon .The way the house is laid out  the water to the kitchen is the farthest away from the source and I've toyed with the idea of a point of use .I've yet to do it .I never run out of hot water with two showers and the washing machine running but it takes a long while to get hot in the kitchen sink .

doc henderson

I do not know the cost, but for the kitchen being far away, there is a valve that can be retrofitted under the sink, and it allows the hot water line to slowly feed back via the cold water line and keep hot water close to the faucet.  also, ground water here is a bout 60 degrees so if the heat pump gets you to 120, and you just have to boost to 160 that would be a savings.  the heat pump would need to be constant and the higher temp only from electric and or gas to make up the difference.  
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Al_Smith

A recirculation loop could be an option I had also considered .The Heat pump on my lady's water heater was air to water,ground water had no part in it .
 I have a geo thermal heat pump which does use water to air .It could have been ordered with a second heat exchanger to go from water to water to use as a water heater .I opted not to .The more bells and whistles the more components  to fail--and will .
What will happen on a heat pump water heater is the thing will collect condensate under certain conditions .Remember a heat pump is in effect an air conditioner running backwards .One side gets hot,the other side gets cold .
Who ever installed that high priced thing was not much of a plumber because it should have had a drip pan and a bottom drain .They were either too stupid or     just plain tight wads taking advantage of a grandmother who didn't know any better .Typical large metro area contractor .No matter she sold the place and now resides with me in the big midwestern corn field .

samandothers

I appreciate the feedback.  The idea of $ savings on operating is attractive and may pay off fairly soon but that depends on use.  Our use is just the two of us now.  We do plan to spend some time in the mountains so our time in one place will be shorter.  The up front cost and the concern of how it will hold up, more things to break I believe will steer me to the standard electric heater.  I am spoiled by longevity of the heaters in my home now.  27 years on 2 40 gallon A O Smith.  

Thanks for the input and experiences.

Ianab

Quote from: doc henderson on February 18, 2020, 08:51:07 AMI do not know the cost, but for the kitchen being far away, there is a valve that can be retrofitted under the sink, and it allows the hot water line to slowly feed back via the cold water line and keep hot water close to the faucet.


When my Uncle built his house he actually fitted a small conventional hot water cylinder under the kitchen bench to solve that problem.  It only had to supply the kitchen sink and dishwasher. The shower / bath / laundry etc were at the other end of the house on a regular size water heater. 

But with only 3 ft of pipe to the tap it was like having instant hot water, and no losses from the long run of hot water pipe. Recirculating water would keep it warm at the tap. but at the cost of all the lost energy as the water in the pipe cools. 
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peakbagger

Several states offer rebates on installing these units. GE came out with a line of them and had a bunch of warranty issues to the point they stopped selling them. Other companies have better product. Its a mix of two technologies.  Its a refrigerator that runs "backwards" instead of moving heat out of insulated box and getting rid of it from an outside coil, it takes the heat out of the outside coil and move it into an insulated tank to heart water. The parts are the same as refrigerator. It really needs to be in warm basement. While its doing its thing it also acts as dehumidifier so if you have damp basement you get dehumidifying "for free". The heat pump is not sized for a long term hot water load but the tank provides some storage. The heat pump usually does not heat the water up as hot so the trick of running the tank real hot and blending it with cold water to stretch out the storage doesn't work as well. The other technology is a calrod resistance heater, the same thing used in any electric hot water heater. it kicks on when they tank temp gets low. If used normally they do cut the electric bill by 2/3rds. Most of the reports I have heard is except for the GE units they work well. 

Do note if you have aggressive water that eats water tanks its going to eat the hybrid electric water heater. BTW the normal name for these is Heat Puum Hot Water heaters. 

samandothers

Interesting peakbagger.  

I may consider one in our existing home for the bed room side.  

I was looking at Rheem units.

Al_Smith

The catch 22 on some of those rebates or allowances of energy saving devices are so trivial  it's not worth the paper it's written on .I get exactly one dollar a month from my electric bill by having a geo-thermal heat pump .It's hype and hoopla .--don't get me started ---

florida

I don't think you'd ever save enough on electricity to pay the difference. Hybrids are about $1,500.00 not including installation. I've never heard anything good about them but have heard a lot of bad. When we remodeled my sones house he bought one and had it delivered. The plumber happened to be there and told him to send it back and get a regular water heater. He said they have so many problems that a year in and it will be working just like a regular one. It does blow cold air when the water is heating but It has lots of insulation so it doesn't run much. I can't imagine it having any real cooling effect in a typical garage
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samandothers

I appreciate the feedback.  As much as I'd like for them to work I am not sure they are ready for prime time.  

Maybe all conventional electric this time round.  I have two 40 gallon electric heaters in our home now.  They are 27 years old and still working, but I am getting nervous.   I am starting to have dreams/nightmares of leaking tanks while we are out of town.  No drain pans on these so water would be in the basement... whatta mess that would be.   They sit on a couple pieces of small steel angle.  I need to check into the code now for water heat installs and make a plan.  Like me, they are not getting any younger.

peakbagger

Electric hot water heaters can last a long time if they are drained on occasion to remove sediment from the bottom and just as  importantly that the sacrificial anodes are changed out before the disappear. Most folks dont even know they are in there but their job is to rot instead of the tank. Unfortunately they dont protect from corrosion cells that can form under a deep layer of sediment in the tank bottom, thas why you need to drain them on occasion. There are special flood saver valves that can be installed if there is a pan. If the tank leaks and fills up the pan it causes a component in the valve to expand and automatically close off the water to the tank.

If you dont know about the anode here is plenty of info Hot water heater anodes and rust protection

samandothers

Sadly I was bad, drained first time after about 20 years.  then have done it about every 2.  Tried to loosen the anode in one to no avail.  Code require a drain pan now?

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