We all know geothermal heat pumps are ultra-efficient and can save you up to 75% on your heating costs, but did you know they can also help you save money in other areas of your home’s energy consumption? That’s right, your geothermal heat pump will also save you up to 55% on your hot water cost using a desuperheater.
How Geothermal Water Heaters Work
Heat pumps reduce hot water costs through a component called a desuperheater. While most geothermal heat pump manufacturers have this as an add-on, all of our residential heat pumps come with a desuperheater included for domestic hot water preheating.
The discharge gas from the compressor is significantly hotter than the condensing temperature, and condensing is the main heat source for space heating. A desuperheater is a small double-wall heat exchanger that takes this extra heat from the discharge gas and puts it in your domestic hot water tank.
In layman’s terms: A geothermal heat pump heats your home using a compressor. The compressor produces extra heat, which is what we use to preheat your domestic hot water tank. The desuperheater harvests the extra heat using a pump and heat exchanger and deposits it into your electric hot water tank.
Since we are harvesting waste heat, the desuperheater does not affect the heat output of the geothermal heat pump. Also, since we can only harvest the heat when the compressor is running (when the geothermal heat pump is operating), we can’t supply 100% of your domestic hot water needs. Instead, it is estimated that a desuperheater can provide between 50% and 60% of your domestic hot water requirements. Your hot water tank provides the rest of the heat.
Desuperheaters operate in both heating and cooling mode, but the greatest savings occur in heating mode and the savings while in cooling mode are relatively small. Overall it evens out to 55% year-round.
How Much You Can Save With a Geothermal Water Heater
Just how much can you expect to save on your electricity bill? Let’s look at the following example to get some real world numbers.
According to the U.S. Energy Information Administration, domestic hot water heating makes up approximately 17.7% of your home’s electricity consumption.
Source: eia.gov
So, if you spend on average $350 per month on your electricity bill, here’s how much of that is due to domestic hot water use:
$350 x 17.7% = $61.95/month
$61.95 x 12 months = $743.40/year
So if you install a geothermal heat pump, you’ll save between 50-60% on your domestic hot water costs. Let’s split the difference and estimate a 55% savings rate. That means you’ll save:
$61.95 x 55% = $34.07/month
$34.07 x 12 months = $408.87/year
That’s significant yearly savings on top of the 75% you could save on your heating bills. Geothermal heat pumps provide cost-effective heating and cooling, but their benefits go far beyond that. The desuperheater comes with all our geothermal unit; it is just one of the many pros of this innovative heating technology.