How does a heat pump work?

A diagram of a house with a ground source heat pump system.

A heat pump forms the backbone of the temperature control systems in many homes throughout the state of Maryland. At its core, a heat pump is a technology that transfers heat between two areas with different temperatures. Heat pumps allow you to directly add or remove heat from your home to reach your desired temperature. Heat pumps are used to modulate temperature in many different types of HVAC systems, including geothermal systems and decentralized air conditioning systems.

Thermodynamics 101

To understand the basic principles that define how a heat pump works, it helps to have a crash course in thermodynamics. The 2nd law of thermodynamics describes how heat flows spontaneously from a hot to a cold body. So, if there is hot air inside the house and it is cool outside, the air inside the house has a natural tendency to want to flow to that cooler space. To flip that example: if the air outdoors is hotter than the air within your home, the warm air from outside will naturally transfer heat to the cooler interior until both bodies are at a similar temperature.

Heat pumps allow you to get around the 2nd law of thermodynamics by strictly regulating the transfer of heat. Heat pumps enable you to use energy—such as that harnessed via electricity—to move heat from the cooler space to the warmer space. Heat pumps transfer heat energy into an intermediate substance stored within the refrigeration coils, which is then used to distribute the heat through your home’s HVAC system or expel it from your home.

Air-source heat pump

Air-source heat pumps work with the heated air outside of your house in order to maintain your home’s indoor climate. The air-source pump’s reversing valve is used to determine the direction that the heat flows, either inward or outward. As a result, your system can transfer heat from your house to the refrigerant in the system, before releasing it into the air outside during the hot summer months. In the winter, the reversing valve allows the system to work in the opposite direction: in this case, the heat is captured from the cooler air outside and brought inside to heat the home.

Carrier makes a large line of heat pumps that provide numerous options for energy efficient heating and cooling for your home, including the Infinity Series.

Geothermal heat pumps

In addition to sourcing heating from the air outside, heat pumps can also harness geothermal energy to maintain a comfortable climate in your home. Once you go far enough below the surface of the earth, the temperature is extremely consistent and changes minimally from season to season, if at all. This continuous and renewable resource is a never-ending source of heat for your home’s pump-based HVAC system.

The first step of installing a geothermal-based heat pump system for your home is to install a ground loop under the property. A ground loop is a long length of pipe, or pipe coils, which is installed deep under your property to reach the area of consistent temperature. These pipes are then filled with water to store the geothermal energy and transport it to or from your home.

Contrary to the method employed by air-sourced pumps, the heat from your home is transferred to the liquid inside your ground loop, rather than directly to the outside air. The heat is then distributed evenly throughout the ground deep below your home. Much like the outdoor climate, the earth’s potential to store energy is too massive for it to be truly impacted by any amount of heat transferred from a single home. This makes the earth an ideal heat source for winter months or heat sink for hot summer days.

Other characteristics of heat pumps

Heat pumps have a few other characteristics that are important to know about. Firstly, heat pumps are typically most suitable for use in fairly moderate climates. A heat pump will have an easier time maintaining the home’s climate at a comfortable temperature if you do not experience extreme heat or cold in your area.

Secondarily, heat pumps can be combined with other HVAC technologies like furnaces or air conditioners to create hybrid systems—creating maximum comfort for your family. Be sure to discuss whether a hybrid system might be an option for your home with your heating and cooling professionals.

It is also worth mentioning that heat pumps are an extremely energy efficient way to control the temperature in your home. Compared to traditional furnaces or air conditioners, heat pumps often require less energy to achieve similar heating and cooling results. As a result, heat pumps can be a great way to contribute to a greener environment while also saving you money on your heating and cooling expenses each month.

Is a heat pump right for you?

If you are considering having a heat pump installed in your home, the best initial step you can take is to contact one of the heating and cooling experts here at Presidential Heating & Air Conditioning. Every home throughout DC and Maryland poses unique challenges when it comes to heating and cooling. Our specialists have seen it all, and can work with you to evaluate both your needs and the realities of your home in order to come up with the most efficient and effective solution for your family.

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