In July 2014, I purchased this GE GeoSpring heat pump water heater to replace my existing all-electric water that had sprung a leak. Admittdely, it was an impulse buy because Lowes was having a sale on them – probably to get rid of unwanted inventory because these have horrible reviews!
So why did I buy it? Because it was only a few hundred dollars more than a conventional electric water heater and I’d been wanting to get an integrated HPWH after my previous add-on HPWH died after just a year. Plus, based on the negative reviews, I felt that the people having problems were using earlier versions of the heater. So I’m crossing my fingers and hoping that it has a long, happy life.
Almost everything written in this article applies to all heat-pump water heaters. I’ll put the GE specific notes at the end.
What is a heat-pump water heater?
You may not know it but your refrigerator and air conditioner are examples of heat pumps. Through a process of compression, condensation and evaporation, they move heat from one place to another. In your refrigerator, that humming you hear when it runs is the compressor. The inside of the fridge is cold because the “heat” in the fridge is moved to the outside of the insulated box and blown into your kitchen. An air conditioner works exactly the same way – it cools the air inside the house and expels the heat outside.
The HPWH does the same thing except it uses the heat to warm the water in the tank. And the cold? If you feel the output behind the heater, you’ll see that the cold gets blown into the room. Heat the water, chill the room. Keep this in mind, we’ll come back to that later.
Why does a heat-pump water heater save energy?
Why would you spend twice (or more) the cost of a regular electric water heater? Because of the energy savings! Whether you want to reduce your electric bills or do what’s right for the environment, a HPWH promises to save lots of energy. How much? 50%-75%.
To answer the “why”, let’s look at how water heaters work.
A standard electric water heater works exactly the same as those coils you plug in and stick in a cup of water. Electricity flows through a wire, the wire heats up and that heat is transferred to the water. This process is about 99% efficient (excluding other losses outside your house). Electricity comes in, heat goes out. Simple. But if it’s 99% efficient, how can you save so much? That’s the magic of science!
A HPWH heats water indirectly through a process of compression, condensation and evaporation (sound familiar?). Instead of heating a piece of wire, the HPWH runs a compressor and a small fan. Remember, it works by *moving* heat from one place to another. So this process moves heat from your room into the water. The energy required is for the compressor and fan which is able to move heat into the water two to three times more efficiently than that electric wire.
Remember what I said about your refrigerator being a heat pump? In theory, if you put the hot coils (usually located under the fridge) in water, you would be heating water with your fridge, saving even more money! In the future, I believe more household appliances could be combined to virtually eliminate waste. But I digress…
So through magic, um, I mean science, the HPWH is able to heat water much more efficiently than a simple electric coil.
Added benefit – air conditioning and dehumidification
Previously I mentioned that the HPWH blows out cool air as a side effect of using a heat pump. A HPWH therefore acts as a small air conditioner! This is great in the summer when you want to cool your house. It may not be great in the winter, when you’re trying to heat the house!
You know that air conditioners also create a trickle of condensate. This is water extracted from the air that condenses on the cold coils. In the same way, the HPWH creates water that must be disposed of. If you’re lucky, you have a drain in the utility room where you can run the condensate line. Otherwise, you’ll have to pump the water to a drain line. It’s a small thing, but something you have to think about.
If you’re like most people, you’ve got the water heater in a utility room in the basement. Basements are usually somewhat humid so that dehumidification is welcome. This gives you an added energy savings because you might not have to run that energy-hog dehumidifier as much if you have a HPWH.
As an example, this summer, while heating water for my family of three, the HPWH produces about a gallon of water every day. That’s a pretty good amount of water being extracted from the air! And it’s noticeable. My utility room is distinctly cooler and drier than it used to be.
What if you don’t want cold air blowing into the room?
All modern HPWH’s let you select modes. For the summer, I set mine to heat the water 100% using the heat pump, so it’s most efficient. That’s also when it blows out the most cold air. When it’s cold out, you can switch it so that it acts like a conventional water heater and only uses electric heating coils to heat the water. In this mode, it’s silent and there’s no cold air or dehumidification. There’s also no energy savings.
In my case, I’ll use it year round because it’s in a basement utility room that’s effectively sealed off from the rest of the house. I want the dehumidification and having a room that’s a bit colder is good – I’ll use it as a cool storage room for food, just like a root cellar.
But if you’ve got it installed in your living space where you don’t want a cool breeze during the winter, you can always go back to normal electric heating mode so you get the best of both worlds.
Keep in mind, it’s not going to let your house get freezing cold. GE says: “In order to protect the heat pump system and for highest efficiency the GeoSpring heat pump will operate between 45°F – 120°F. Anything below or above this temperature range will cause the water heater to automatically operate in standard electric mode to continue to provide hot water.”
For the most part, installation of a HPWH is the same as any other electric water heater. Set it in place. Connect electric wires and plumb it in. It’s an easy job. But there are a couple extra considerations:
- As noted, you need to provide a place for the condensate to drain
- It extracts heat from the room, so you must install it in a room large enough to provide that heat without sucking too much warmth from the room. That means no small closet installations.
- It’s taller than an equivalent capacity water heater. Basically, take a normal 50 gallon water heater and add a foot to the height.
GE has specific recommendations as follows:
“The GeoSpring water heater should be installed in a clean, dry area as near as practical to the area of greatest hot water demand to prevent long un-insulated hot water lines from wasting energy and water. It is designed to go into any common indoor installation area including basements, attics, closets, and utility rooms. If the room is smaller than 700 cubic feet, the room should have a louvered door or a door which has vents installed near the top and bottom of the door. Each of these vents should have an area of 240 square inches.”
Install it. Get hot water. No special thought required if you don’t want to think about it.
However, if you want to take full advantage of the HPWH, you’ll want to familiarize yourself with it’s special features.
The photo to the right shows the control panel of the GeoSpring I’m using. You can see five modes:
- Heat Pump
- High Demand
There’s also up/down arrows to set the temperature and a couple other items. As you can see, I have mine set to 130F and the little green indicator light shows that it’s in heat pump only mode.
To make things easier, GE has also provided a description of each feature. These are described below:
- Heat pump only – exactly as indicated. Uses the heat pump for all the water heating. This is the most efficient mode but also the slowest to heat water and which cools the air the most. Note – by slow, it means it takes about an hour to reheat the tank fully after it’s been depleted. I’ve never found this to be a problem for multiple people taking showers, but if you take long showers or need to fill a bath, you have to consider this.
- Hybrid – uses both the heat pump and electric coils. This senses your operation, preferring to use the heat pump but uses the electric coil as needed to increase the ability to keep up with hot water demand.
- High demand – this mode tells the water heater that you’re going to be using a lot of water and forces it to use the electric heater even more to provide a greater hot water capacity.
- Electric – switches off the compressor and uses this exactly like a conventional electric water heater.
- Vacation – according to GE FAQ: “This feature is used when the homeowner is away from home for an extended period and hot water is not needed. In this mode, the temperature will drop the water temperature down to 50°F and will use the most efficient heating mode to conserve energy while the heater is sitting idle. The unit will automatically resume heating one day before the programmed return, so that hot water will be available.”
Real-life Energy Savings
So what’s the bottom line?
Before switching exclusively to the HPWH
As you know, I’m The Energy Geek, so I monitor everything. Prior to installing the GE GeoSpring heat pump water heater, I had three water heating systems in my home:
- Boiler fired water heater (connected to my oil fired boiler)
- Conventional electric water heater located below my wife’s shower (instant hot water, yay!)
- Small electric water heater located below the kitchen for dishes, hand-washing and laundry
I had a complex method of deciding which heater to use when. The heater under the kitchen always operated so that we’d get hot water for hand and dishwashing in a couple seconds rather than running the tap for 1-2 minutes before getting hot water (due to the weird plumbing in my house).
I used the electric water heater below my wife’s bathroom enabled all the time, but during the winter, I fed it how water from the main heating system boiler. This let me use heating oil (about half the cost of electric heating in my area) and a little electric as needed to maintain water temperature. Located where it was, it gave my wife instant hot water when washing hands and taking showers.
The boiler supplied the rest of the house, which really meant my bathroom and another bathroom.
It’s something of a crazy configuration but it optimized energy use and water savings. All told, during the summer, we used about 4 kilo-Watt hours (kWh) of electricity and 1/3 to 1/2 gallon of oil every day for a total cost of about $2/day for hot water at my utility costs.
After switching exclusively to the HPWH
Part of my switch-over to the HPWH was changing the plumbing so that I could more effectively use the HPWH as my single hot water source.
First, I ran a direct, 1/2″ water line to the kitchen from the utility room. Previously, the water had to travel a tortured path and used 3/4″ pipe. The larger pipe has more water capacity (2.3 gallons per 100ft) than the 1/2″ pipe (1.0 gallons per 100ft). This means I waste less water and get hot water faster to the kitchen. Plus, with the shorter run, it was even more efficient.
Next, since I’m in the process of switching my boiler, I’m not using any oil to heat water. In the future, I’ll have a new, high efficiency propane boiler that I can use for hot water during the winter, but I’ll cover that in a future article.
So how much energy am I using now? My daily electric use for water heating ranges from 2 to 5 kWh per day, averaging 3.19kWh. That equals $0.32 to $0.80 per day, with an average of $0.51/day – a savings of $1.49. Put another way, my water heating bill is now just about 25% of what it was before!
Is a heat-pump water heater worth it?
Assuming that I’m able to maintain it and it lasts just as long as a conventional electric water heater, how much am I saving?
For the moment, assume that the savings for the entire year equal what they are now – $1.49 per day. That about $540/year. Even if I don’t save as much during winter operation, I’ll be saving at least $350/year. That’s a payback on my investment in 1-3 years. For me, that’s a complete no-brainer! What other investments can I make that will yield 33%-100% return on my investment per year?
A quick comment on this – I’m assuming that the additional cost of the HPWH is $500-$700 compared with a simple electric heater. The numbers are back of the envelope and depend on your energy costs. I live near Philadelphia where electricity costs about $0.16/kWh and heating oil is $3-$4/gallon.
Summary of the pros and cons of a heat-pump water
- It saves money – water heating electric bills will be 1/2 to 1/3 compared to a conventional electric water heater
- It blows out cold air – effectively acts as a small air conditioner in the room where it’s installed
- It dehumidifies the air (more on this later)
- It costs more – You’re going to spend $1,000-$2,500 (USD) instead of $300-$700. Note, this is before installation costs
- It’s more complex – compressor, electronics and fan are more to break than a simple electric coil
- It blows out cold air (this can also be a benefit)
- Slightly more complex installation – it needs a place for the condensate to go
- Needs to be installed in an appropriate location
- It heats water more slowly than a pure electric water heater
- It makes noise like your refrigerator
All in all, after a month of operation, I’m very happy with this investment. The water heater has worked like a champ and is saving real money every day. What the long-term will bring, I don’t know. Hopefully, it won’t die in a year or two like some people have reported. But I’ll update if anything changes. Until then, I highly recommend heat pump water heaters for anyone currently using a conventional electric water heater and the time has come to replace it.