Heat pump water heaters–an interesting choice, but not a one-size-fits-all solution


An evolving water-heater technology has been moving more mainstream over the past couple of years.  This technology uses a heat pump (think air-conditioner working in reverse), to heat the water.  I’ll focus on GE’s GeoSpring Hybrid water heater for discussion purposes.

GE's "hybrid" water heater

The good news is that this technology is ready to roll.  Heat Pump Water Heaters (HPWH) can be twice as efficient as a standard electric resistance water heater, and that increased efficiency can add up to big savings over time.  This can be a great choice for many homeowners.

It’s not for everyone, however.  In most cases, if you heat you water with natural gas, it won’t make sense to switch to the heat pump.  This does depend on things like the gas and electric utility rates, usage patterns, and climate.

The GE model is only available in a 50-gal tank, and it won’t provide either the capacity nor the efficiency benefits for high-usage situations.  The heat pump is more efficient, but it takes long to recover—that is it takes longer to make the water hot.  To compensate for this there is a standard heating element that you can use to speed things up in “high demand” situations.  In fact, you can set it to standard mode and it will function just like a regular electric resistance heater.  However, the more you heat water using the electric element instead of the heat pump, the less you save.

Because of the compressor and fan, a heat pump water heat does make some noise while it’s running—about the same as a full-size microwave.  Since water heaters are often in basements, garages, or otherwise isolated from the living space, this may not be an issue.  But it’s something to be aware of.

In simple terms, the heat pump uses heat from the air and transfers it to the water.  A secondary effect is that it cools the air around it.  This is actually a nice side benefit in cooling climates.  However, in colder climates where you’re paying to heat your home for much of the year, in some sense you’re robbing Peter to pay Paul, and I don’t think this technology makes sense in the northern U.S., snow country.  In the north, where inlet water temps (the temperature of the water is it hits your home from the city lines or your well) can be quite cold, you’ll also be in the “high demand” mode much of the time, again, reducing your savings.

Height can also be issue, and this won’t fit in some shorter crawlspace where a “low-boy” water heater is needed.

Bottom line:  A HPWH can be good choice in cooling climates where you heat your water with electricity—especially where electric rates are high.  Not the best choice if you already heat with gas or see snow for half the year.


Tags: , , , , , , ,

3 Responses to “Heat pump water heaters–an interesting choice, but not a one-size-fits-all solution”

  1. I’m liking the Vertex water heater « GreenHomes America Says:

    […] exciting addition to the mix.  I still like the possibility of heat pump water heaters, and their hybrid cousins, but more so in warmer climates.  And solar water heating is a simple renewable […]

  2. Home Sweet Home Says:

    Water Heater To Save Energy…

    To save energy and money, most people are willing to do the little things but too often they do not know what options are available to them. Well, if you use an American of millions of homeowners, the electric heat storage water tank, one of those litt…

  3. The Home Renovation Guide Blog Says:

    Stay Warm…

    A fire refers to the building structure, which contains the fire used for heating and sometimes also for cooking. A combustion chamber consists of a fireplace or fire pit fire, which, together with a chimney, which is used to smoke and other gases that…

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: