At what temperature should I turn my heat pump to emergency heat?

Author: Cassidy Kris  |  Last update: Tuesday, January 20, 2026

However, what happens when it is too cold outside for the air to be pulled in and heated normally? This is where emergency heat comes in. Typically, this setting on your thermostat kicks on when the temperature is anywhere between 30 to 35 degrees Fahrenheit.

When should you run emergency heat on a heat pump?

Use emergency heat only if your heat pump isn't heating your home at all. That'll keep you warm until a professional heat pump contractor can come repair it.

At what temperature is it too cold for a heat pump to work?

Heat Pumps Don't Actually Stop Working

Contrary to popular belief, heat pumps don't ever stop working when it's cold. These systems are built to withstand frigid weather, operating at 100% efficiency even down to -13 degrees Fahrenheit.

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 do heat pumps become ineffective?

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 Emergency Heat Mode And When To Use It On A Heat Pump

At what temperature should I lock out my heat pump?

Lockout controls minimize use of strip heat, maximizing energy savings. Incorrect lockout settings result in the majority of inspection failures. PTCS Spec: Set auxiliary heat lockout to 35°F or lower.

Do heat pumps stop working in extreme cold?

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.

Should I use auxiliary heat or emergency heat?

The difference between emergency heat and auxiliary heat is that emergency heat has to be switched on manually and should only be used in temperatures of 30 degrees or below. However, auxiliary heat will kick on automatically to help heat your home more quickly if there is a sudden drop in temperature.

What happens if auxiliary heat runs too long?

This can cause concern, as auxiliary heat typically is not supposed to run all the time. While it's normal for auxiliary heat to kick in during exceedingly cold temperatures, running it too long may indicate an issue with the heat pump.

Why is my heat pump blowing cold air?

It's Defrosting

To protect the outdoor coils from freezing up in the winter, heat pumps go through a defrosting period every hour or so in which they are truly blowing out cold air. This defrosting period only lasts a few minutes and should not affect the overall temperature of your home.

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.

What is the drawback of emergency heat?

High energy bills

The cost of running your home on Emergency Heat would be astronomical. Turning to this setting switches the source of your heat from the heat pump to the electric heat strip, which is significantly less efficient and more costly.

At what temperature outside should I turn my heat on?

At What Temperature Outside Should I Turn My Heat On? You should turn your heat on when the temperature outside drops below 55 degrees. This will help you stay comfortable but also avoid costly heating bills. This is also the lowest temperature you'd want your house to get to avoid water pipes bursting.

How cold is too cold for a heat pump?

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.

At what temperature should I switch from heat pump to 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.

How to fix heat pump freezing up in winter?

Run warm water across the sides of your heat pump to begin thawing some of the ice. Do not attempt to use any tools or objects to crack the ice, as this can damage the coil and ruin your heat pump. Your heat pump comes equipped with an automatic defrosting function but try to clear some ice before attempting.

Should I put a heat pump on emergency heat below 40 degrees?

Emergency heat is a backup heating source that your heat pump uses when it cannot keep up with your heating needs or breaks down. While people may switch this system on whenever they feel that the temperatures outside are too low, this is not wise since the EM Heat system is more expensive than a traditional heat pump.

At what temperature should auxiliary heat come on?

Auixiliary Heat will turn on automatically when heat can no longer efficiently transfer heat from the outside air to heat pump. This is when the outside is around 35-40 degrees and the indoor temperature is around three degrees cooler than the thermostat setting.

How long can I run emergency heat in my house?

Your system can technically run in Emergency Heat mode indefinitely. Whether your backup heat source is electric or fossil fuel, it's designed for continuous operation without causing damage.

What temperature to turn on emergency heat?

However, what happens when it is too cold outside for the air to be pulled in and heated normally? This is where emergency heat comes in. Typically, this setting on your thermostat kicks on when the temperature is anywhere between 30 to 35 degrees Fahrenheit.

What is stage 2 heat on a heat pump?

What is meant by Stage Two heating? When the thermostat on a dual-stage furnace reads “Stage 2,” it implies that the furnace is operating at the higher setting, giving you 100 percent of its capacity. Usually, the lower setting of a dual-stage furnace is sufficient to provide household comfort almost 80% of the time.

Will a heat pump automatically switch to emergency heat?

The system automatically switches to emergency heat at these extremely low temperatures to ensure your home stays warm. This transition is seamless, but you may notice a slight increase in your energy bill during these periods.

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.

Will a heat pump work at 0 degrees?

Your heat pump will still work below freezing and below 15 degrees. It will continue to perform below 0 degrees or colder. It just won't be as efficient over those very coldest days of winter as using a gas-fired furnace.

What is the most reliable heat pump brand?

6 Qualities of the Best Heat Pump You Should Know
  • 1- Daikin. ...
  • 2- Mitsubishi Electric. ...
  • 3- Bosch. ...
  • 4- Carrier. ...
  • 5- Trane. ...
  • 6- Lennox. ...
  • 7- Goodman. ...
  • 8- Rheem. Rheem heat pumps are known for their high-quality construction and energy-saving features.

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