Monkeying around with water heating controls

While watching the winter Olympics I saw the great ad for the new GE GeoSpring hybrid water heater.  If you missed the ad with the snow monkeys chilling out in the heated water it can be seen here.  The new GE hybrid water heater is called a hybrid because it is a combination of an electric water heater and an air-source heat pump.

GE describes how the unit works in the GeoSpring Hybrid water heater features:

A compressor and evaporator are integrated into the electric water heater unit and the evaporator draws in ambient heat from surrounding air using two variable speed fans. Condenser coils wrap the tank all the way to the bottom to transfer this heat into the tank and heat the water.

This innovative process creates the same amount of hot water as a traditional electric water heater, but can reduce water heating expenses up to 62% to save $320* per year. And that could have a dramatic impact on monthly utility bills for years to come!

On the link describing the water heater's ability to save energy GE states: "Cut water heating energy usage by up to 62%". It seems that they arrive at this number by comparing the Energy Factor (EF) of their hybrid heater (2.35) to that of a standard electric water heater (.88).  Energy Factor is defined by the DOE as:

The energy factor (EF) indicates a water heater's overall energy efficiency based on the amount of hot water produced per unit of fuel consumed over a typical day

I have no doubts that the hybrid water heater from GE is more efficient than a standard electrical water heater (the electric water heating energy cost calculator GE puts up on their site helps), but what about compared to heating with another water heating method which is natural gas?  To compare this you would need to compare the EF of a natural gas water heater to the GE hybrid heater while also taking into account the cost difference between what you pay for natural gas vs. electricity...which will mean you will probably have to do a conversion between therms (the units usually used to express natural gas consumption) and kWh (electric consumption).   It obviously gets a little complicated when comparing different methods of heating water!  This page from the California Energy Commission (CEC) is a great resource for comparing water heating methods.

The CEC estimates that heating with natural gas will cost users 1/3 the cost of heating with a standard electric heater...but if the GE hybrid heater is 3 times more efficient than a standard electric water heater then a natural gas heater and a hybrid water heater from GE would cost users the same amount to operate! ***this obviously depends on the rate you pay for natural gas and electricity

One of the Mapawatt team members has an electric hybrid water heater that is even more efficient than GE's; but only because his hybrid water heater is electric and solar thermal.

If you're interested in buying the new GE heater, the good news is that you are probably eligible for an energy star appliance rebate!  Using their online water heater store I determined that the GeoSpring has a list price of $1,699, but this doesn't include any installation costs.  Here's my advice if you are in the market for a water heater:

  • If you definitely need a new water heater and you heat with electric, then the GeoSpring seems like a great choice.  Do some more research, install one, and tell us how it works!
  • If you already have an efficient electric water heater than you will have to compare the initial purchase price (minus rebates) vs. your annual energy savings.  Yes, this requires a little more work on your part but you will be smarter afterward.
  • If you heat with natural gas chances are it may be hard to justify the higher initial purchase price of the GE water heater.  Do the analysis though and don't be afraid to ask for help in the comments below if you need it!
  • If you want to live off-grid then you can't use this water heater anyway (unless you had solar PV or a wind turbine and wanted to use that electricity for a water heater?).  Just install a solar thermal water heating system and take cold showers when it is raining outside :)
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Comments

Has anyone had any repairs needed on their GE GeoSpring Hybrid Water Heater? Or any flooding from it?
Yes my broke when it was about 6 month old. The GE repair man said they had a problem with the evaporator condensor and they had to replace mine. Since then I had nothing but problems with my GE heater. Now it says I need to replace both upper and lower elements it is about 1 1/2 years old. So I called GE again and they said you are out of warranty and they will only pay for parts not labor to fix it. Even with the repair history I had with this thing. I call every time I had a issue with this thing and the lady I spoke with said she would document the problems. Now they tell me that they only have a record of me calling once. I am ready to rip this thing out and throw on their front lawn. Be careful for all the money you have to spend on this thing it takes a long time to recoup your money,that is if it works properly.
What is the maximum temp water can be heated. I'm considering using it for radiant heat.
Maximum set point is 140 degrees F - probably not enough for radiant heat.
I'm using the GEO Spring GE water heater. It replaced an oil fired stand-alone water heater in my unheated basement in NY. I like it so far (after a month). It is quieter than a window AC, slightly noisier than a refrigerator, about the same as my salt water fish tank. The water heater is next to an oil fired hot air furnace. The furnace is much louder than the water heater. Family of 4 gets all the hot water we need with temp set at 124 degrees. I may reduce the temp another another degree or two. The control is digital, with 1 degree steps. I leave the unit in 'hybrid mode' which mainly uses the heat pump, but will use the two electric elements when it detects that it's running low on hot water. Other setting vary the switch point between the elements from 'heat pump always' to 'hybrid' to 'high demand' which switches earlier to the elements and 'elements only'. The heat pump is 700 watts according to the sticker, so should be putting 1500 to 2000 watts of heat into the water. This compares with the 4000 watt rated elements. Water heats faster with the elements. I've not had a problem with amount of hot water staying in hybrid mode, but do not know how often the unit used elements instead of ht heat pump. When the heat pump is off there is no way to know if the unit is using elements or if it has enough hot water. In the summer I used to run a dehumidifier in the basement. The hybrid water heater acts as a dehumidifier so I'm expecting not to need to run the dehumidifier, and to save that cost. There is insulation between the basement and the upstairs. The basement moves from 45 degrees to 65 degrees depending on outside temp (a radon system pulls air under the slab making the temp swing more than normal). I don't expect to benefit from colder basement air in the summer, or lose much heat to colder basement air in the winter. The heat pump is more efficient when the temp is higher, so I think I'm getting closer to 2X efficiency than the 2.2X advertised, but that's a guess. I wish the electronics gave details on how often the heat pump ran, how often elements were used, etc. The hard part of the install was getting rid of the oil fired unit (300+ lbs, chimney, oil lines) and running electric service. I already have a condensation pump from a central AC, so my only extra was figuring out how to keep the condensate line from freezing in the winter. I'm going with heat tape on the copper output line and see if that works. (Doing nothing doesn't work in NY, the line freezes) Net, I think I'm saving 250-300 gals of oil a year, and am going to spend $30-50 more for electricity most months (less in the summer) and a $1000 more for purchase/install than a replacement oil fired unit would cost. (My old oil fired unit was leaking and had to go). With oil at over $4/gal here that's a clear winner for me, and I really like using electricity rather than oil.
ckmapawatt's picture
Great review! Keep us updated!
According to the tag on the GE hybrid water tank, it cost about $198.00 to operate a year. That works out to about $16.50 month to operate. Not knowing how much it cost to operate a regular water heater I have been noticing the energy use from last year to this, month by month. Last month we only had to use the electric heater once so it gives me a good idea of what my savings is. It came to $19.50 less than the same month last year. I used 440Kwh this month and used 710 last year for the same month. I expect that to get better as the air bets hotter.
Can anyone tell me what the network interface jack is on the side of the GeoSpring water heater is for?
We have no natural gas to my house, which is common here in south Florida, so gas water heater is not an option. Old tank is in un-A/C garage and essentially zero risk of freeze. Lowes currently offering 10% off if bought online, plus tax credit too.
This sounds like a great idea except for one thing. If one of these is installed INSIDE the home, it is going to take heated air from the home to heat water and put cooler air out into the indoor environment. Seems to me like this is going to INCREASE my heating cost! Has anyone looked into this? Is the heat pump portion efficient enough to draw heat from a cold space (like a garage?) Does it still offer the same savings if placed in a garage?

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