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How Does a Heat Pump Work?

HVAC cleanliness

How Does a Heat Pump Work?

  1. Refrigerant is sent outside the home to the evaporator coils.
  2. A blower takes in the warm air from the outside and puts it through refrigerant
  3. The refrigerant takes in the heat and cools the outside air
  4. The heat circulates to the inside of the home
  5. Evaporator coils put the air into the compressor
  6. The compressor presses the refrigerant into a warmer, high pressure gas
  7. The high pressure gas then cycles into condenser coils, which liquefies the gas
  8. The heat taken from the refrigerant is put into the home
  9. The liquid goes through an expansion valve
  10. The expansion valve reduces the pressure of the refrigerant
  11. The refrigerant is taken back outside to be reheated

Heaters are built into HVAC units. In the summer, the HVAC will pump the heat outside and circulates cold air inside.

This is thanks to the reversing valve. The reversing valve pumps refrigerant in a certain direction depending on if you have activated the heating or cooling function.

When the reversing valve is turned to cool, it directs refrigerant out of the home to get heat out. When it is set to heat, it pumps refrigerant into the home to expel heat.

The system is performing the same function as it does in the summer with your air conditioner: expel hot air. The big difference is the location of that hot air.

How does the system absorb heat from the cold air?

Refrigerant is designed to absorb heating, turning it into a gas. The side effect of refrigerant is that it cools down the surrounding area fast.

In the winter, refrigerant absorbs heat from cold or freezing temperatures. The heat gets absorbed from the air, but comes at a price: it freezes the HVAC.

The machine goes into the defrost cycle to counteract ice buildup. The defrost cycle switches the reversing valve back to the cooling mode of the summer. This pumps the hot refrigerant through the machine, clearing off the ice from the heater by raising the temperature of the system.

The outdoor fan that blows out cold air is turned off during the defrost cycle. This speeds up the process by keeping all heat inside the unit until properly defrosted.

During the cycle, auxiliary heat is activated on the inside. This pumps any extra heat across the house, keeping the home warm while the HVAC heats up again.

This method of heating your home cuts electricity use with other space heaters by as much as 40%. The economy of the heat pump makes it perfect for Texas winters. When the weather is no longer cold, the reversing valve switches to cool and functions as an air conditioner.

Still have questions about your heat pump?

If you live in the Austin area and want to learn more (or just need your heat pump repaired), contact Stan’s Heating and Air Conditioning. Our HVAC and heat pump experts are standing by and waiting to help you.