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How to Fix Heat Pump Problems in Cold Weather

I love providing useful every day tips that help make people's lives better, easier, and more affordable.

Heat pump operating in below freezing conditions

Heat pump operating in below freezing conditions

A heat pump is an essential piece of equipment for the heating of many buildings, but you may find yourself running into heat pump problems in cold weather, which can be a frustrating and potentially dangerous problem. Heat pumps are designed to work in all types of weather (including cold weather) but when it's extremely frigid out, the pump may struggle to pull in heat from the outside air. By understanding why heat pumps lose efficiency in the cold weather you can recognize the reason behind component failure and take steps to fix the problems.

Heat Pump Problems In Cold Weather

Ideally, a heat pump works best when the temperature is above 40 degrees. As the weather cools off, most heat pump models will still work perfectly well at temperatures below freezing.

How cold is too cold for a heat pump to work?

Systems typically do not operate as efficiently when temperatures drop to between 25 and 40 degrees Fahrenheit. And once outdoor temperatures drop to 40 degrees or lower, heat pumps start to struggle because they consume more energy and start losing their ability to function.

Extremely low temperatures can increase the risk for hypothermia and even frostbite.

Extremely low temperatures can increase the risk for hypothermia and even frostbite.

Troubleshooting Problems

Heat pump problems in cold weather are actually fairly easy to resolve if you look at the common causes and troubleshoot from there. Generally speaking, the pump may have become damaged by snow and ice, causing airflow restriction or breakage of the unit itself. It is less likely that the inside components have been damaged as a result of outside elements, but it could be possible due to the added stress on the pump.

Here are five troubleshooting steps to find the cause of your heat pump problem:

1. Heat Strips: When electricity passes through coil-like components called heat strips, heat is produced. These strips disperse that heat into your home when the system fan blows air across them. A heat pump system uses heat strips to make up for its inability to maintain a set temperature in extremely cold weather. Your backup heater or auxiliary heat strips might be inadequately sized or not functioning at all.

2. Fuse Failure: If wiring inside the air handler or in its electrical box is damaged or crushed by snow or ice, a fuse failure may result. If your heat pump’s fuse has failed, you should replace it right away to restore heat before extreme weather conditions persist. You may not need to call a technician to replace your pump's fuse; it is possible to save yourself a service call fee and replace the fuse yourself.

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3. Blockage: An obstruction in the airflow from the outdoor compressor to the indoor coil may cause a water block. This could then freeze, causing the unit to malfunction or fail completely. To allow the heat pump to function at its best, the area around the cabinet should be cleared of snow at all times.

4. Airflow: Heavy snow and ice on the pump's outdoor compressor may trigger too much airflow in the unit. This could cause the unit to fail because the system can't handle any more air pressure. If there is only a small amount of ice, it may melt away quickly, but if it persists for a long time or keeps accumulating, it is a problem that needs to be solved right away.

5. Breakage: In extremely low temperatures, your heat pump may completely freeze and crack. This compromises the efficiency of the unit, changes the airflow, and could also be a potential safety concern. If this happens, turn the unit off immediately and call a technician.

What to do when your heat pump is frozen

In normal operating conditions, condensation on the heat pump freezes. So a little bit of outer frost is perfectly normal. The heat pump does have a defrost mode where it can handle melting some ice that accumulates on top. But, you have a problem that a technician needs to resolve if the frost persists or begins to spread to other parts of the unit. If your heat pump is completely frozen, call a technician right away.

What to do if your heat pump is blowing cold air

If you feel cold air coming from your vents, there may not be cause for immediate alarm. Your heat pump may just be doing its job correctly by maintaining the set temperature. Start by checking your thermostat setting to make sure that the air conditioning switch hasn't been activated by mistake. You may want to call a technician if your thermostat is indicating a cold temperature, as this could be a sign that your heat pump has malfunctioned.

What to do when your heat pump is not working at all

One of the worst heat pump problems in cold weather is when a unit stops functioning altogether and is unable to provide any source of heat to the building. In extreme weather circumstances, lack of warmth may pose a potential risk to life. In this situation, call a technician immediately to explain your concerns. They are trained and equipped with the proper equipment to solve the problem safely and as quickly as possible.

In the meantime, it is advisable to have an alternative source of heat available, such as a propane heater. Without using electricity, propane heaters are an efficient way to heat a room; newer models even claim an efficiency of up to 99%. They also offer an inexpensive and practical alternative heating method. Using liquid propane as fuel, these heaters can quickly heat a medium- to large-sized space.

External heat exchanger of an air source heat pump restored to working condition

External heat exchanger of an air source heat pump restored to working condition


Having a properly working heat pump is critical for heating many buildings, but you may well run into heat pump problems in cold weather, especially due to blockages and damage caused by snow and ice. Follow these five steps to get to the root of the most common heat pump problems. If you're still experiencing problems, you could always contact your local mechanic for quick service and repair. And if you live in an area where the temperature drops below 40 degrees Fahrenheit, you may want to consider buying a backup source of heat to ensure that you remain warm during the cold winter months.

This content reflects the personal opinions of the author. It is accurate and true to the best of the author’s knowledge and should not be substituted for impartial fact or advice in legal, political, or personal matters.

© 2022 Louise

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