As a heating system expert with years of experience in HVAC industry, I can provide you with a comprehensive explanation regarding the operation of auxiliary heat in air source heat pumps.

Auxiliary heat, also known as "backup" or "emergency" heat, is an essential feature in air source heat pumps. It is designed to provide additional heat when the heat pump is unable to efficiently extract heat from the outside air. This usually occurs when the outdoor temperature drops below a certain balance point, which is typically around 35 degrees Fahrenheit.

The heat pump operates by transferring heat from the outside air to the inside of your home. However, when the outdoor temperature is very low, the heat pump's efficiency decreases. This is because the heat pump has to work harder to extract the heat from the colder air. At some point, the heat pump can no longer efficiently transfer heat, and that's when the auxiliary heat kicks in.

The thermostat in your home plays a crucial role in this process. It constantly monitors the indoor temperature and compares it to the set temperature. When the heat pump is unable to maintain the desired temperature, the thermostat senses this and automatically activates the auxiliary heat. This is signaled by the "AUX" heat light turning on.

Auxiliary heat is typically provided by electric heat strips or a furnace that is part of a dual-fuel system. These heat sources are more energy-intensive than the heat pump, but they are necessary to ensure that your home remains warm and comfortable during extreme cold weather.

It's important to note that while auxiliary heat is effective, it is also more expensive to operate than a heat pump. Therefore, it's best to use it sparingly and only when necessary. Regular maintenance of your heat pump and thermostat can help ensure that the auxiliary heat is only activated when it's truly needed.

Additionally, it's worth considering the overall efficiency of your heating system. If your heat pump is old or not properly sized for your home, it may rely more heavily on auxiliary heat, leading to higher energy bills. Upgrading to a more efficient model or ensuring that your current system is correctly sized can help reduce your reliance on auxiliary heat.

In summary, auxiliary heat in air source heat pumps comes on when the outdoor temperature drops below the balance point, and the heat pump can no longer efficiently extract heat from the outside air. The thermostat senses this and automatically turns on the electric heat strips or furnace to provide the additional heat needed, signaling this by turning on the "AUX" heat light. It's essential to maintain your heating system and consider its efficiency to minimize the use of auxiliary heat and reduce energy costs.

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The balance point (when it can no longer efficiently transfer heat from the outside air) of an air source heat pump, is usually about 35 degrees. The thermostat senses this and automatically turns on the electric heat strips to provide the additional heat needed. It signals this by turning on the "AUX" heat light.read more >>