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What is a Heat Pump and How Does it Work?


A heat pump system moves heat from one place to another within a pressurized chemical refrigerant. It can provide both heating and cooling this way.

How do heat pumps work in the summer?

  • Warm indoor air is passed over a liquid refrigerant, which absorbs the heat and evaporates into a low pressure gas.

  • The gas goes through a compressor, which raises its temperature and pressure.

  • The hot gas moves through an outdoor coil, releasing its heat to the relatively cooler air and condensing back to a liquid.

  • The liquid moves through an expansion valve to release pressure, which cools it down.

  • Then it gets piped back into the house to collect warm air.

How do heat pumps work in the winter?

  • The same process also works in reverse.

  • When the refrigerant has low enough pressure, it will be colder than the outdoor air and can absorb heat from the surrounding air.

  • As the refrigerant moves back into the house, adding pressure increases the temperature.

  • Then the heat is blown out by an air handler, either through ductwork as in a conventional system or directly from the unit, as in a mini-split system.

How does a heat pump save energy?

  • Heat pumps require less fuel and operate very efficiently, because they primarily move heat, rather than generating it.

Want to learn how this could affect your project specifically?

Book a free Q+A with the architect! On this 30 minute phone call, you'll speak directly with Architect Liz Saunier about your project. The purpose of this call is to:

  • Understand your project goals and aspirations

  • Discuss your current situation and resources

  • Explain our process at a high level

  • Provide you with next steps based on your objectives and current situation


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