How Does a Heat Pump Work in Heating Mode?

There will never be a blizzard in Los Angeles and the surrounding areas (unless you’re in Big Bear), but there are plenty of days of cold weather where going outside isn’t ideal. In these moments, it’s best to stay warm and cozy indoors with a heat pump system running, but how does a heat pump work in heating mode?

Heat pump systems may be newer technology compared to gas furnaces, and at Monkey Wrench, our technicians receive technical training on how all heat pumps operate. To install, maintain, and fix heat pumps, our technicians are knowledgeable in how these systems work inside and out to serve homeowners interested in these systems better. 

If you’ve ever wondered or had doubts about how heat pumps work for heating, this article will highlight it all for you. We’ll break down how a heat pump’s different components work together to produce warmth inside your home. This information will help you determine if you want to go with a heat pump or seek alternative heating methods for your home.

How Does a Heat Pump Warm a Home?

Heat pumps use a heating cycle that relies on ambient temperature outside to warm your home. The heating process starts with the outdoor unit of the heat pump absorbing air from outside. Even when it’s cold outside, the absorbed air contains heat, which is separated inside the heat pump and heated up further before it’s expelled inside by fan motors.

As simple as the heating process may sound, it is only possible with several crucial components within the air-source heat pump.

• Refrigerant: The refrigerant switches between a gas and liquid state as it helps produce warm air. It interacts with the ambient air and the rest of the parts mentioned below to heat up as it cycles in the heating process. 

• Compressor: The compressor raises the temperature of the refrigerant by pressurizing it. 
• Evaporator coil: When it’s in heating mode, the coil in the outdoor unit of a heat pump acts as an evaporator. It carries the low-temperature liquid refrigerant as it begins the heat absorption process. 
• Condenser coil: When a heat pump is set to heating, the coil within the indoor unit acts as a condenser. The condenser coil releases heat, mixing with air passing over it to produce warm air. 
• Expansion valve: The expansion valve helps regulate refrigerant flow and depressurizes it to restart the heating process all over again. 
• Reversing valve: This crucial part of a heat pump is what allows it to switch between cooling and heating modes.  

You can refer to these terms as we go into further detail of a heat pump’s heating process. The heating cycle begins with heat absorption.

Heat Pump Heating Cycle: Heat Absorption

The heating process starts the moment you set your heat pump onto heating mode through the thermostat. It begins with the coil within the outdoor unit of the heat pump. The coils carry low-temperature, low-pressure refrigerant in a liquid state. 

Even when it’s cold outside, the refrigerant is much colder. So, as the outside air passes through the evaporator coil, it is absorbed by the cold refrigerant liquid. Heat naturally moves toward areas with less heat, which makes it easy for the refrigerant to absorb the latent heat from the outside air. 

The heat causes the refrigerant to evaporate and turn into a vapor while the outside air is released back outside. Once the refrigerant turns into a vapor, it makes its way to the next step in the heating process.

Heat Pump Heating Cycle: Compression

Even though the refrigerant contains heat, it isn’t enough to warm up your home. That’s where the heat pump compressor comes in.

The heat pump compressor squeezes the gaseous refrigerant to raise its temperature and increase its pressure. The superheated, high-pressure refrigerant gas is now ready to move to the indoor unit of your heat pump to continue the heating process.

Heat Pump Heating Cycle: Warm Air Release

Once the heated refrigerant gas reaches the condenser coil within the inside unit, it is ready to be distributed. Fans inside the heat pump blow air over the coils, and the air absorbs the heat from the refrigerant. The heated air is then transferred throughout the homes via ductwork.

The heated air warms up your home until it reaches the desired temperature. As the heat is transferred to the air, the refrigerant condenses. The refrigerant is then again turned into a liquid state, approaching the final stage of the heating process. 

Heat Pump Heating Cycle: Refrigerant Cools Down

The liquid refrigerant doesn’t deplete after it transfers heat to warm your home. Instead, it continues the heating cycle by transforming into a cold liquid ready to absorb latent heat from outside again.

To do this, the refrigerant is transported to the expansion valve via refrigerant lines. The refrigerant arrives at the valve as a high-pressure liquid. The expansion valve helps decrease the pressure of the refrigerant, resulting in a drop in its temperature. 

The refrigerant is once again a low-pressure, low-temperature liquid that is then moved to the evaporator coil in the outdoor unit, where it’s ready to absorb heat from outside again. 

Unlike the refrigerant within a car’s air conditioning system, heat pump refrigerant doesn’t deplete; it will continue to cycle within the heat pump system unless there’s a leak somewhere.

Does a Heat Pump Warm a Home as well as a Furnace?

Heat pumps are just as effective in heating a home as a furnace. One of the most significant differences, however, is that heat pumps tend to be more energy efficient than natural gas furnaces. Natural gas furnaces need to consume energy to produce heat, whereas heat pumps use existing heat to warm up homes. 

In terms of comfort, heat pumps tend to have less fluctuations in heating capacity than natural gas furnaces. Still, both systems are capable of achieving their goal of keeping homes throughout Los Angeles warm during cold days. 

Is a Heat Pump Worth it for Keeping My Home Warm?

Heat pumps use emerging technology to heat your home efficiently on the coldest days in Los Angeles and the surrounding counties. Now that you’re familiar with how they operate at a technical level, you can decide if this heating system is the right choice for your home.

Although many homes have traditional furnace and air conditioning packaged systems, we’ve seen how heat pumps are growing in popularity. At Monkey Wrench, we work with the top brands in the industry, such as Lennox and Goodman, to provide homeowners with the latest and greatest in heat pump systems.

If you’re interested in a new heat pump system or want maintenance done, contact us using one of the buttons below. You can also book directly through our online HVAC scheduler.