How Does a Heat Pump Work?

Some people swear by heat pumps and feel they are an excellent investment in reducing the costs associated with the energy it takes to keep a house warm or cool. Others don't understand why someone would want to pay an average of $2,000 for a metal monstrosity that sits in your backyard.

Perhaps an explanation of how heat pumps work can help someone decide whether a heat pump is a good investment or a money pit.

Heat Pumps: The Basics

Heat pumps work by drawing heat from the surrounding environment and pumping it into another environment. Some of the main parts of a heat pump include an outdoor coil, refrigerant, a compressor and an indoor coil. No matter how hot or cold it is outside, there is almost always heat associated with that temperature. The outdoor coil is responsible for taking that heat. The cost comparison of heat pumps to electric heating is far less because a heat pump is continuously moving all year long, never sitting idle and pushing energy to stop and start like traditional air systems.

Keepin' it Warm on Cool Days

Air passes over the outdoor coil, which sucks the heat out of it and puts it into the refrigerant. The captured heat makes the refrigerant warm and turns it into a vapor. These vapors travel to the indoor coil that is on the inside of the home. When the indoor air meets the heat in the indoor coil, it gets warm and travels through the home vents, spreading warmth throughout the home.

Keepin' it Cool on Warm Days

The outdoor coil captures the heat from the air just as it does when it intends to warm the house. However, when the warm air meets the indoor coil's extremely cool refrigerant, the heat doesn't last very long. It gets absorbed so quickly that the air loses all humidity, which condenses outside of the coil. A fan pushes that super cool air into the ducts.

The refrigerant turns from liquid to vapor in this process because of the absorbed heat. That vapor goes through a special vapor line to the outdoor coil which dissipates the heat, making the vapor a liquid again. That liquid goes through a liquid line back to the indoor coil and once again acts as a refrigerant.