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If you have ever heard of the term “heat pump” from your A/C technician, you might be confused and not even sure what a heat pump is. In this blog, how a heat pump works. But before that, we must first understand what a heat pump is, the benefits, and the components of a heat pump.

What Is A Heat Pump?

In the most simple terms, a heat pump is just your air conditioning system working in reverse. While your A/C cools your home and pumps heat outside, a heat pump would pull hot air from the outside and blow it into your home.

In more scientific terms, a heat pump transfers heat from one place to another using the HVAC components. While a heat pump cannot create hot air, it can move heat from one place to another.

Benefits of a Heat Pump

Because heat pumps rely on the use of electricity to move air from one place to another, they are extremely cost-effective and efficient. In comparison, electric heaters like a space heaters, need a lot of electricity to operate.

In fact, according to, today’s heat pump can reduce your electricity use for heating by approximately 50% compared to electric resistance heating such as furnaces and baseboard heaters.

In addition, high-efficiency heat pumps also dehumidify better than standard central air conditioners. This again makes these systems more efficient and creates more comfortable environments.

Components of a Heat Pump

Heat pumps rely on many components to work together.

Outside Unit

The outside unit is typically called the A/C unit. The outdoor unit contains a fan and coils. The fan helps move air through the coils while the coils hold the refrigerant.

Indoor Unit

The indoor unit is also sometimes called the air handler, furnace, heat pump, or A/C as well. This unit contains a fan and coils as well. The fan helps blow the air through the coils and throughout the ductwork in the home.


The refrigerant is what is located inside the copper coils. This stuff, also called freon, 410A, or R22 (depending on the type) easily changes temperature by pressure changes. It is the same thing located in your fridges and freezes to keep it cold.

The refrigerant moves through the coils from the outside unit to the indoor unit and back.


The compressor is responsible for increasing the pressure of the refrigerant, moving it throughout the system, and making it hot.

Reversing Valve

The reversing valve basically helps the refrigerant switch directions. As mentioned in the beginning, a heat pump is your A/C in reverse.

Expansion Valve

The expansion valve acts as a regulator on the refrigerant helping it meet the proper pressure and temperature.

Heat Pump Diagram

How a Heat Pump Works

So now that we know what a heat pump is and the components, we can talk about how a heat pump actually works.

In general, a heat pump uses electricity to transfer heat by using refrigerant as the medium. Fans blow air over the coils of the refrigerant to blow warm or cool air throughout the home.

Cooling Mode

heat pump diagram in cool mode
  1. In the above diagram, the refrigerant travels through the compressor which is located at the outdoor coils. This makes the refrigerant have higher pressure converting it into a hot gas.
  2. Then, the gas flows to the outdoor coils which are functioning as the condenser. A fan pushes cool outdoor air through the coils. Naturally, the refrigerant absorbs the cool outside air and lowers its pressure. The air blown through the coils becomes warm air.
  3. Then, the refrigerant goes through the expansion valve which regulates the pressure. This makes the refrigerant a colder liquid for it to pass through the indoor unit functioning as the evaporator
  4. The indoor unit pushes warm indoor air over the fan. This blows cool air throughout the home and makes the refrigerant warm again causing it to evaporate.

Heating Mode

Heat pump diagram in heating mode
  1. When the A/C is reversed, we have the heat pump. The refrigerant travels through the compressor which makes the refrigerant a hot gas.
  2. The hot gas travels through the indoor coils. A fan blows cool air over the coils which transfer warm air into the home.
  3. The refrigerant absorbs the cool indoor air and lowers its pressure. It then travels through the expansion valve which regulates the pressure back to a cold liquid.
  4. The cold liquid travels through the outdoor coils which blow warm outdoor over the unit. The warm air transfers heat energy to the refrigerant once again to travel through the compressor.

Final Thoughts

While a heat pump can be confusing it’s an awesome technology uses natural properties to transfer heat.

Call Waypoint Property Inspection to inspect your home in Tampa, St. Petersburg, Lakeland, Orlando, Palm Beach, Ft. Lauderdale, and surrounding areas.