Intro to Heat Pumps

Learn how heat pumps work and how to measure their efficiency.

Heat PumpsYou probably never thought that you could use your heater to cool your property. But with a heat pump, that’s exactly what you get a two in one system that can be configured to cool or heat your property as needed. Here are some important things you need to know about heat pumps.

How Heat Pumps Work

The principle behind a heat pump is the ideal gas law, which describes a direct relationship between the pressure and the temperature of a gas. As pressure rises, so does temperature, and as pressure falls, temperature does too. The heat pump makes use of this process by having a gas to expand in one side of the system and contract in the other.

In cooling mode, gas is allowed to expand in the indoor portion of the system, which draws ambient indoor heat into the gas. Then, the gas gets pumped to the other portion of the system and pressurized until it turns into a liquid. The liquid now pushes heat out into the outdoor air, “dumping” it. Then it can return back to the other side, ready to absorb more heat. When the system is switched to heating mode, the cycle reverses so that the heat gets released into the indoor environment. In most cases, the two portions of the system are housed in a single unit with the indoor portion being fed indoor air and the outdoor portion receiving outdoor air.

Heat Pump Ratings

When selecting a heat pump, you may encounter some of the following efficiency measurements:

COP (coefficient of performance): This measurement tells you the amount of heat energy moved for every unit of electric energy used at a given outdoor temperature. The higher the number, the more efficient the system. Heat pumps can have a COP of 2 to 5 for heating and 3 to 12 for cooling.

EER (energy efficiency ratio): This measurement shows the efficiency of a cooling system and is useful for comparing your heat pump to an air conditioner. The EER is the amount of cooling per hour divided by the amount of electricity used, assuming it is 95°F outside.

SEER (seasonal energy efficiency ratio): This measurement is very similar to the EER with the exception that it provides a picture of average efficiency over an entire cooling season rather than on a single 95°F day. Higher SEER ratings are better, with most heat pumps ranging from 15 to 20.

HSPF (heating seasonal performance factor): This measurement is basically SEER for winter. Most heat pumps hover right around 10 HSPF, meaning they transfer 10 times more energy as heat than they consume as electricity. Remember that heat pumps become much less efficient at temperatures below 40°F, so in a mild California winter your unit may be more efficient than the rating indicates.

Need Help?

If you need help selecting or installing your new heat pump, come to the experts at General Heating & Air Conditioning. We have an excellent selection of highly efficient Carrier heat pumps to choose from.