Will a heat pump work at 20 below zero?

Author: Delphine D'Amore  |  Last update: Wednesday, May 14, 2025

As long as your house is properly air-sealed and insulated, an air-source heat pump can perform well beyond temperatures of -13 degrees Fahrenheit! Some newer models can handle temps as low as -22 degrees.

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

Below 40° f or 5° C the heat pump will frost up and need to turn off to allow the exterior unit to melt. The thing is though, about 10 years ago or longer, heat pumps started to have four-way valves that would switch between cooling and heating.

Do heat pumps work in sub zero?

While heat pumps do become less efficient in subzero temperatures, many models still operate close to normally in temperatures down to minus 13 degrees Fahrenheit, or minus 24 Celsius.

At what temperature is a heat pump no longer effective?

For this reason, heat pumps start to lose efficiency at around 40 degrees F and become less efficient than furnaces at around 25 degrees F. Heat pumps continue to be effective at cooling the indoors, even at high temperatures. In the South, it rarely gets below 25 degrees.

What is the 20 degree rule for heat pumps?

Simply put, it means you should never set your thermostat for a temperature more than 20 degrees cooler than the outside air. Why not? Most air conditioning systems can only handle a 20-degree difference between the outside and inside air temperatures.

Heat Pumps Don’t Work In Winter??? (Sub Zero Temps)

At what temperature does a heat pump switch to emergency heat?

This heating method works incredibly efficiently until the outdoor temperature reaches about 35 degrees. At this point, the heat pump has difficulty extracting enough heat from outside to keep up with the thermostat setting. This is when many people assume it's time for switching their heat pump to emergency heat.

What is the lowest temperature a heat pump can operate at?

What temperature does a heat pump quit working? As long as your house is properly air-sealed and insulated, an air-source heat pump can perform well beyond temperatures of -13 degrees Fahrenheit! Some newer models can handle temps as low as -22 degrees.

Why doesn't my heat pump work when it's cold?

If you aren't getting enough heat from your heat pump, you should check the outdoor unit first and foremost. Is the outside of the unit casing covered in ice? If so, you may have a broken defrost cycle. As the outdoor unit leeches heat from the air, it creates condensation that then freezes on the outside of the unit.

What temperature should a heat pump switch to a gas furnace?

With a typical operation of a hybrid heating system, the heat pump will operate with ambient temperatures above 32 degrees. When temperatures are below 32 degrees, the gas furnace will operate. To keep the heat pump from running, homeowners should switch their thermostats to “emergency heat” mode.

What is the lowest operating temperature for a Mitsubishi heat pump?

Enjoy unparalleled heating performance from one of our all-climate heat pump systems with Hyper-Heating INVERTER® ( H2i ®) technology. Hyper-heating systems can perform at 100 percent of rated capacity in outdoor ambient temperatures as low as 5° F with guaranteed operation down to -13° F.

Can a heat pump work below zero?

Yes, there are heat pumps that work in below-freezing temperatures. Actually, heat pumps are a very practical option for homeowners who experience cold winters.

Can heat pumps freeze in cold weather?

A heat pump doesn't have much of a chance when moisture is building up during freezing temps. When the pump is too low to the ground, there is nowhere for moisture to drain, and it quickly turns to ice when it's cold outside.

What is the COP of a heat pump in the winter?

While their performance drops, they can still perform well. Gibb and colleagues found that between 5°C and −10°C, the average COP was around 2.7. We get 2.7 units of heat for every unit of electricity we use. It also meets our heating needs at a much higher efficiency than gas boilers or electric radiators.

Should you turn off your heat pump in extreme cold weather?

Air source heat pumps work efficiently in heating and cooling modes, making them a versatile choice for year-round comfort. Unlike boilers or furnaces, which cycle on and off to maintain a comfortable temperature, heat pumps can run continuously without wasting energy.

What is the lockout temperature for a heat pump?

It states that the control for the lockout temperature shall have a maximum setting of 40 degrees F, and set for 32 degrees or less at final inspection.

How can I help my heat pump in extreme cold?

7 Tips for Maximizing Heat Pump Performance in the Winter
  1. Stop cranking up the temperature. ...
  2. Don't rely on emergency heat. ...
  3. Keep your filter clean. ...
  4. Keep leaves and debris clear of your outdoor unit. ...
  5. Do NOT cover your system. ...
  6. Don't worry about the defrost mode. ...
  7. Follow a regular maintenance schedule.

At what temperature does a heat pump shut off?

Heat pumps do not operate as efficiently when temperatures drop to between 25 and 40 degrees Fahrenheit for most systems. A heat pump works best when the temperature is above 40. Once outdoor temperatures drop to 40 degrees, heat pumps start losing efficiency, and they consume more energy to do their jobs.

At what temperature should a heat pump switch to auxiliary heat?

Homeowners should expect auxiliary heat to turn on during colder temperatures, especially under 40 degrees. Your heat pump is an amazing appliance that can efficiently extract warmth from the outdoor air and transform it into cozy comfort inside your home.

At what temperature does a heat pump become ineffective?

Most standard heat pumps will function at 100% efficiency until the outside temperature reaches about 40° F. However, when the temperature dips below this, most heat pumps are not able to maintain efficiency. They become much less effective at temperatures between 20° F to 30° F.

What temperature is too cold for a heat pump?

Depending on the model, heat pumps tend to be less efficient as temperatures dip below 40 degrees Fahrenheit. At approximately 25 degrees, most heat pumps will still be more efficient than traditional furnaces or boilers.

How to unfreeze a heat pump in winter?

Turn the heat pump off at the circuit breaker. You don't want it to suddenly energize while you're working on the problem. Next, grab a garden hose and spray the heat pump with water until the ice melts. Hammering or chipping away the ice could cause major damage.

Why is my house so cold with a heat pump?

Once you understand how a heat pump operates, we can explore some possible reasons why a heat pump might blow cold air, such as incorrect thermostat settings, clogged air filters, a dirty outdoor unit, or issues with the reversing valve.

Will a heat pump work at 0 degrees?

Most cold-climate heat pumps can run at total capacity until the outdoor temperature gets to about 5 F or below. It will still heat your home at those lower temperatures, but not necessarily keep it as warm as you may typically like. That's where backup heat sources come in.

When should I use emergency heat on my heat pump?

So now we know that Emergency Heat is basically when you use your supplemental heat by itself. When should I use Emergency Heat? As the name implies, it is only used in emergency situations. It is used when there is something wrong with first-stage heating (the Heat Pump itself).

What is the lowest setting for a heat pump?

For winter heating, aim for the lowest comfortable setting, around 68-70°F when occupied. Recommended configuration includes: Set the system to “heat” or “auto” and increase the temperature to 68-70°F during occupied hours. Program the thermostat to lower temperatures to around 62-65°F when away or asleep.

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