If you are considering solar, the odds are good that you are also interested in being energy efficient in general. The most efficient way to heat a home is using an electric heat pump (aka “mini-split”), and the most efficient way to heat hot water is with a heat pump water heater.* Heating your home is roughly 40 percent of the average homeowner’s annual overall expense for power (the other two slices of the pie are 40 percent for transportation – largely gas, and 20 percent for household electricity). So switching to heat pumps to heat your home significantly drops your oil/propane/etc. bill while bumping up your electric bill.
But if you can power that additional electricity demand with a solar Tracker – electricity that can be up to 25 percent less expensive than what your utility charges – you can see overall savings well into the $1,000’s. Click here to learn more.
What exactly is a heat pump?
A heat pump is an electrically powered device that captures energy from one place, concentrates it, and delivers it as heat to another place. A window air-conditioner is a familiar type of heat pump, which captures energy from your indoor air and moves it to the outdoors. The result is a cooler indoor space and a (very slightly) warmer outdoors.
When people use the term “heat pump,” they are usually referring to a system that runs in the opposite direction: it captures energy from the outdoors and uses it to warm the indoors. “Cold-climate heat pumps” are versions specially designed to operate down to very low temperatures. Depending on the model, they can capture usable heat from the outdoors even when outdoor temperatures drop as low as -18°F.
Similarly, a heat pump water heater captures heat from the air in your basement and uses it to heat water for your shower and sinks.
The nature of the heat pump cycle means that heat pumps deliver useful heat far more efficiently than systems that generate new heat directly. This translates into energy savings and associated monetary savings.
If you start heating your home and/or water with heat pumps, this will reduce the amount of propane or heating oil you were using previously, while increasing the amount of electricity you are using. In almost all cases, the energy you will use with a heat pump will be a good bit less than what you would be spending on fossil fuels. This is, of course, especially true if your electricity is generated with a solar Tracker.
So how much electricity will you use with a heat pump? According to Vermont’s Green Mountain Power (GMP), for example, use of a cold climate heat pump of the following sizes will result in approximately the following change in electric usage and cost. Naturally, the exact electricity use will vary from home to home based on many factors.
|Heat pump BTU rating||Avg. monthly bill increase||Avg. monthly kWh increase||Annual bill increase||Annual kWh increase|
|9,000||$26||163 kWh||$312||1,950 kWh|
|12,000||$37||231 kWh||$444||2,775 kWh|
|15,000||$47||294 kWh||$564||3,525 kWh|
|18,000||$63||394 kWh||$756||4,725 kWh|
As for a heat pump water heater, here’s what that looks like.
|# people||Gallons used per day||Average electricity usage to heat water||Cost @ GMP residential rates|
|1||19.5||716 kWh/yr||60 kWh/month||$10 per month|
|2||35.8||1,315 kWh/yr||110 kWh/month||$18 per month|
|3||52.0||1,910 kWh/yr||159 kWh/month||$26 per month|
|4||68.2||2,505 kWh/yr||209 kWh/month||$34 per month|
|5||84.4||3,101 kWh/yr||258 kWh/month||$42 per month|
You might also want to take a look here, to see what your options are for powering an electric vehicle with solar, and here to learn about the electricity requirements when switching to an electric dryer or oven/stove.