Ready to Jump to a Heat Pump?

A heat pump is a device that can heat or cool a space using electricity. They can replace a gas burning furnace and dedicated air conditioning unit. They do not burn any fossil fuels onsite, making them environmentally friendly.

Heat Pumps work by moving heat from outside to inside. As long as it is above absolute zero outside, there is thermal heat energy. So, even if it is really cold, heat pumps can transfer that thermal energy to inside your home.

This is the same process an air conditioner uses to move thermal energy from inside your home to outside. A heat pump is just air conditioner that can also run in reverse. That means you can also use a heat pump to cool your house.

Heat pumps can be very efficient because they don't create any heat all, they are just moving it from one place to another using electricity. In fact, heat pumps can move more thermal energy than they consume.

COP is a measurement of how effectively a heat pump uses electricity to move heat from place to place. The COP measures the ratio of how much useful heat (or cold) a heat pump will produce if we give it certain energy input.

Typical COPs for heat pumps range from 2 to 4 meaning they deliver 2 to 4 times more heating energy than the electricity they consume

Compared to furnaces or a space heater, heat pumps do not create heat. Instead they just move it from one place to another.

As a result, the COP of a heat pump is generally over 1! This means that they move more energy than they consume.

Yes, it is calculated with the following formula:

COP_{heat pump} = T_hot/(T_hot-T_cold)

T_hot is the indoor temperature in Kelvin

T_cold is the temperature in Kelvin outside when the heat pump is running

Let's take a day where we want to heat our home to 70°F (~294K) and the outside temperature is at freezing 32°F (~273K). In this case, the theoretical maximum COP is 294 294 / (294 - 273) = 14 COP.

In practice, the COP will be much lower, but this shows what's possible!

The Technology Connections channel on Youtube has several videos on heat pumps. This one is a great overview for installing one.

The Wire Cutter also has a guide. Read it here.

In many situations, the electricity that powers a heat pump will have been generated by burning a fossil fuel. However, because heat pumps are more energy efficient than burning gas on site, they can still reduce carbon emissions from heating your home.

To break it down a bit more, power plants can convert natural gas into electricity with 40-60% efficiency¹. That means a heat pump with a COP of at least 2.5 or as low as 1.66 can generate more heat energy than burning natural gas on site.

Modern heat pumps can readily achieve those COPs in a wide range of conditions making them an environmentally-friendly choice today even if the power is coming from fossil fuels.

¹ The National Academy of Sciences

The latest generation of variable-speed air source heat pumps work well at outdoor temperatures as low as -15°F¹.

As a back up, you can use a gas burning furnace or electric resistive heating.

To determine the number of days a year you might need backup heat, checkout the Backup Days Calculator.

¹ CLASP

If everyone used heat pumps, it would put additional strain on our electric grid. However, one study estimates that the United States could support 97% of our heat load without creating new peak energy loads if we maintained a fossil fuel back up for the coldest days¹. That would buy us time to do the necessarily energy grid enhances for the final 3% of our heating needs

¹Electricity Load Implications of Space Heating Decarbonization Pathways

While this site mainly focuses on using heat pumps for heating, they can just as well cool a space by running in reverse. When operating in cooling mode, a heat pump is the same as an air conditioner.

Please go to our about page and send us a your question so we can answer it here for everyone!