How Does a Heat Pump Work?

Traditional HVAC systems operate on a fairly straightforward principle: air conditioners cool homes during the summer, while furnaces provide warmth in the winter. But what about heat pumps? Unlike conventional systems, heat pumps supply both heating and cooling. Despite their growing popularity, many homeowners don’t understand how these versatile systems operate.

Understanding the Mechanics Behind Heat Pumps

To answer the question – how does a heat pump work? – let’s first delve into its various components and how they operate in tandem to provide heating or cooling, depending on the season.

• Outdoor unit (condenser): Contains a compressor and a coil for extracting heat from or releasing heat to the outdoor air. Typically located at the side of homes, a heat pump condenser is a box-style unit that resembles a central air conditioner.
• Indoor unit (evaporator): Houses the evaporator coil and a fan to distribute the heated or cooled air throughout the home.
• Refrigerant: Circulates between the outdoor and indoor units, absorbing heat from the outdoor air during heating mode and releasing it indoors and vice versa during cooling mode.
• Expansion valve: Regulates the flow of refrigerant, controlling its pressure and temperature to optimize the heat exchange process.
• Reversing valve: Unique to heat pump systems, the reversing valve changes the direction of refrigerant flow between the indoor and outdoor units, allowing the system to switch between heating and cooling modes as needed.
• Ductwork: Like traditional HVAC systems, heat pumps also rely on air ducts to distribute conditioned air throughout homes.

How Does an Air-Source Heat Pump Work?

Heat pumps operate differently depending on whether they’re in heating or cooling mode.

Cooling Mode

During the summer months, a heat pump operates similarly to a central air conditioner. As cold refrigerant passes through the indoor evaporator coil, it extracts warm air from inside the home and turns it into a low-pressure, cool gas.

This heat is then expelled outside as the refrigerant flows to the outdoor unit, where it releases the absorbed heat into the outdoor air through the condenser coil, effectively cooling the home. The process repeats itself until the desired temperature is reached, and the system turns off.

Heating Mode

When the weather turns cold, heat pumps work in reverse to provide warmth. The refrigerant within the outdoor coil extracts heat from the outside air. Heat is then released indoors through the evaporator coil, providing efficient heating.

Even when it’s cold outside, there’s enough heat in the air to effectively cool a home, up to a certain temperature. Conventional heat pumps stop operating as efficiently once the temperature dips below freezing, although leading HVAC companies are building advanced heat pumps that can operate in below-freezing temperatures.

Why Regular Maintenance Matters

While understanding how a heat pump works is valuable, homeowners should prioritize regular maintenance by scheduling a tune-up twice a year, ideally before the cooling and heating seasons

Maintenance helps ensure ideal performance, prevents potential breakdowns, and maintains indoor comfort through the year. Regular maintenance also extends the lifespan of heat pumps and helps maximize energy efficiency, leading to lower utility bills.