It’s All About Reversal
An air conditioning system does not really work by generating cool air, as some homeowners may believe. Instead, it uses its refrigerant cycle in order to remove heat from the air in one’s home, and then to vent that heat outdoors, continuing the process until the desired temperature is met. It may sound like a minor difference in explanation, but it is actually an important distinction, especially when trying to understand how it is that a heat pump is able to heat a home, as well as to cool it.
A component called the reversing valve enables the heat pump to reverse its refrigerant cycle, and in turn the entire basis of its operation. When switched over to its heating mode, a heat pump uses the refrigerant cycle to draw heat out of the air outside. The warmed refrigerant is then compressed in the system’s compressor, which further boosts its thermal energy. The resulting heat is then used to heat air for distribution throughout one’s home. Because heat is transferred and intensified via compression, but not generated via fuel combustion, heat pumps enable homeowners to heat their homes very efficiently and affordably.