When To Use Emergency Heat On a Heat Pump (These Rare Cases)

Having a reliable source of heat in your home is vital. A heat pump offers you just that and allows you to control the environment in your home easily. Most heat pumps have an emergency heat setting which can be really useful but shouldn’t be used all the time.

This guide will explain what it is and when to use the emergency heat on your pump.

Heat Pump Behind a Wooden Paneled House

What Exactly Is a Heat Pumps’ Emergency Heat?

Before you think about using the emergency heat, you need to know what it is. Heat pumps work by pulling in heat from the outside, but where this isn’t possible, then the emergency heat uses a secondary source to provide auxiliary heat.

There are usually heated coils within your heat pump, which, when activated, will provide an intense burst of heat from within the unit itself. This isn’t reliant on other parts of the heat pump or the fan and can be activated from the unit itself.

Every heat pump has an emergency heat setting to support the internal thermostat when the outside temperature gets too low. See more on the differences between these and AC systems in this article.

When Do You Use Emergency Heat?

Emergency heat shouldn’t be used all the time, but they are useful in a few situations:

Freezing Temperatures
Iced Heat Pump During Winter

Your heating pump will work well when the temperature is about 30 to 35 degrees, but below that point, it may struggle.

In very cold conditions, your heat pump won’t be able to draw in warm air to meet the demands of your interior thermostat, and this is when you’ll need an alternative heat source for your home.

The emergency heating coil within the heat pump will kick on or can be manually activated to boost the temperature by a few degrees. This won’t only heat your home; it will help defrost any parts of the pump which may have been frozen by the cold.

It isn’t only those in cold conditions who may need to use the emergency heat, as even those who live in mild conditions can have a few freezing nights a year.

Damage To The Unit

The other common use of emergency heat is when there’s some damage. Heat pumps generally have some components which sit outside of your home. These are needed to draw heat in, and without them, the heat pump can become useless.

Occasionally, they may become damaged by a falling branch or a build-up of debris. If this is the case, you will need to rely on your emergency heat while getting a professional to fix the device.

Why Should You Not Use the Emergency Heat?

Heat Pump Diagram

Emergency heat is, as the name suggests, only for emergencies, and despite the fact it can provide very effective heating, you need to be careful about how and when you use them. When you activate emergency heat, it relies on an electric heat strip. This uses a lot of power and is very inefficient.

To use it regularly would dramatically increase your electricity bill and cost you a lot of money. In fact, on average, it would cost you $30-50 a week to run your heat pump normally, and between $200-250 on emergency heat, so it could cost you 4 or 5 times as much.

By activating your emergency heat, you bypass the heat pump, which puts a great deal of strain on your heating element. Using this for more than short periods of time will cause damage to your device, and eventually, it will stop working entirely.

How To Use Emergency Heat Correctly

Emergency heat should only be used when it’s truly needed. You should never manually turn your emergency heat on unless your heat pump is broken or malfunctioning. Keeping your thermostat on regular heat rather than emergency, even during winter, will help to protect your device and lower your bills.

Instead, you should set your thermostat so that it automatically uses emergency heat as needed. This means that if the outside temperature drops to below 30 degrees, it will kick in and provide extra heat temporarily until the outside temperature increases.

If you do need to activate emergency heat, you should be able to do it directly from your thermostat. Sometimes there is a specific E or emergency button within the thermostat, or if you have a digital device, it may be within one of the settings on the screen. Remember to turn it off again when you no longer need it.

Things You Should Remember About Emergency Heat

Emergency heat isn’t something that everyone knows about, but here are the key takeaways from this article that you should remember:

CITY Emergency Heat System
  • Emergency Heat Is for Emergency Purposes Only – Don’t use emergency heat just to get a quick burst of extra heat. Emergency heat should only be used in specific circumstances and when it’s a real emergency, so do not turn it on too often.
  • The Use of Emergency Heat Can Cause Higher Electricity Bills – Your energy bills will go up dramatically if you activate the emergency heat, and you could see a spike of 300-400% in what you pay.
  • Not All HVAC Systems Have An Emergency Heat Setting – Not every HVAC system will have the emergency heat option, but the majority will. If you live in a cold or mild climate, you should make sure you get one with an emergency heat setting, so you have a protected heat supply.
  • Emergency Heat Mode Comes With A Red Indicator Light – A red light is used to indicate that your emergency heat is activated. If you see this light and didn’t realize it was on, then you should examine the whole unit to see if there are any issues.
  • Emergency Heat Could Be A Life Saver – Emergency heat will provide quick and effective heat when your primary source has stopped working. In the cold winter months, this is essential and can literally save the lives of sick or elderly people.

People Also Ask (FAQ)

Will emergency heat defrost the heat pump?

Yes. Your emergency heat will trigger a defrost cycle and force heat to flow throughout the device. If your heat pump is not defrosting properly, then consult a professional for help.

Does the heat pump automatically switch emergency heat?

Yes, your heat pump should automatically switch to emergency heat when it’s 30 degrees or below. You can activate it manually if there’s an emergency.

How do you wire a heat pump with emergency heat?

To wire your emergency heat, you’ll need to connect the white wire from your heat pump into your thermostat, as this will allow you to activate it as needed. The video below gives a guide on how to wire your heat pump.

What is the difference between auxiliary heat and emergency heat?

Auxiliary heat and emergency heat are basically the same things as heat is provided from a secondary source. Auxiliary heat will turn on automatically when the temperature drops to a certain level, whereas emergency heat will need to be manually activated.


Everybody needs access to heat, and in the winter months, it’s essential for you and your family’s health. Emergency heat gives you access to a secondary heat source even if your heat pump is broken, so you have time to get it fixed. Hopefully, this article has helped explain emergency heat and when you should or should not use it.

Josh Mitchell

Josh Mitchell

My name is Josh and I am obsessed with DIY and improving my family home. HVAC topics can be tricky for homeowners so I decided to share my knowledge on the subject. When I am not working on DIY projects, you can find me at the beach or my local coffee shop.