Based on our preliminary tests in a room with an ambient temperature of 65° to 70°F, the GE GeoSpring electric heat pump water heater has produced energy savings of at least 50 percent compared with a standard GE 50-gallon electric water heater.
An evaporator unit on top of the GeoSpring draws in ambient heat from the surrounding air. That heat is transferred to the water in the tank through condenser coils that spiral around the heater's tank. That's where the savings come in. But when the ambient air isn't warm enough, the heat pump can't keep up to heat the water sufficiently, so a pair of traditional electric heating elements kick in.
Galeotafiore notes that even in the northern United States, the water heater is likely to be in the same room or area as the home's boiler or furnace and that a heat-pump heater would benefit from the heat being delivered from the heating system appliance. (A final point from our tech team: If a heat-pump water is installed in a space that you heat, the heating system for that space might need to overcome the cooling effect the water heater can have on the space.)
If you're considering a hybrid heat-pump water heater, be sure to read the information about installation placement and ambient temperature from manufacturers, such as these details from GE and Rheem.
We're currently conducting further tests of the GeoSpring and the Rheem HP50RH in a space with lower ambient temperatures to see what impact that has on energy savings.
Note that the GeoSpring, HP50RH, and other water heaters qualify for a 30 percent federal tax credit, a cash for appliances rebate in several states, and other government and utility incentives.
Essential information: See our free buyer's guide to storage-tank and tankless water heaters and swap opinions on different technologies and specific models in our water heaters forum.
So if this type of water heater can save 50% over conventional electric water heaters, how does that compare to current gas water heaters?
I just installed the Rheem hybrid water heater. It's quiet and heats up the water very quickly even when it only uses the heat pump to heat water. I had to have a 220 volts electricity line run from the fuse box to the furnace room, but that turned out to be much easier than I expected especially with a 30% tax credit that covers installation. Most importantly, this is an excellent device to use to replace expensive propane; I estimate that I will save about $700 a year with propane at about $3 a gallon.
The short answer to your question is that if you already have a gas hot water heater you are probably better off with it currently based on my number crunching. The longer answer is that you really have to run the numbers yourself to see if this makes sense. I ran the numbers which included figuring out what the average incoming water temperature was in my area, how much water I use and of course my electricity and gas rates. I live in the Mid-Atlantic region and my average electric rate is 11 cents per KWH and my gas is around $1.10 per CCF (both rates include distribution charges as well). Based on those rates this HP hot water heater costs about the same to operate as a standard efficiency gas hot water heater and is more expensive to operate than a high efficiency condensing gas hot water heater.
I have gas to my house but inexplicably my hot water heater is electric. Unfortunately I'd have to pay a lot to a plumber to convert to gas and I'd need to use a direct vent gas hot water heater which is more expensive than a standard hot water heater so this GE makes sense for me especially with the state rebates currently going on (I can also do the installation of this myself). By my math and doing the installation myself this will pay for its premium over a standard hot water heater in 3-4 years and fully pay itself off in 7-8.
The fact that these hybrid water heaters draw heat from heated space raises a little red flag to me. I haven't seen any report yet that shows the cost of the heat that's pumped into the water from the local space (e.g., heated basement). If I put one of these in my attic here in San Antonio, it would draw heat from the almost-always-hot attic air, which is heated by the sun. I wonder how that would compare with a solar panel on the roof, when the lifetime cost is calculated.
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