Finance

EM Heat Meaning: What It Is and When You Should Use It

Published by Molly Famwat on April 28, 2025

Understanding the em heat meaning can be confusing for many homeowners, especially during the cold winter months. When temperatures drop and your heating system struggles, you might notice an “EM Heat” setting on your thermostat. But what does it really do? How is it different from regular heating? This blog will explain everything you need to know about em heat meaning, its purpose, and when you should use it.

What Is EM Heat Meaning?

The em heat meaning refers to “Emergency Heat,” a backup heating option used in heat pump systems. A heat pump typically works by pulling heat from outside air and transferring it indoors. However, when the outside temperature falls too low, or when the heat pump system is damaged, the heat pump cannot operate efficiently. In such cases, the system switches to Emergency Heat to keep your home warm.

Unlike the standard heat pump operation, Emergency Heat does not draw heat from the outdoors. Instead, it uses a secondary source, often electric coils or a gas furnace, to produce heat inside your home. This method ensures you remain comfortable even if your primary heating system fails.

How EM Heat Works

When you manually switch to Emergency Heat, the thermostat bypasses the normal outdoor heat pump. Instead, it activates the backup heating source directly. Understanding em heat meaning is crucial because running on Emergency Heat continuously can lead to much higher electricity bills.

Your system is designed to use Emergency Heat only when absolutely necessary. In some modern thermostats, Emergency Heat turns on automatically when the system detects a problem. In others, you must manually switch it on.

Feature	Heat Pump	Emergency Heat
Heat Source	Outside air	Electric coils or gas furnace
Activation	Automatic	Manual or automatic
Energy Efficiency	High	Low
Usage	Regular heating	Only during emergencies
Cost to Operate	Lower	Much higher

This table explains why using Emergency Heat continuously without need can be costly.

Signs You Might Need to Use EM Heat

Recognizing the right time to activate Emergency Heat is important. If you want to understand em heat meaning properly, you must also know when it is required.

You should consider using Emergency Heat if:

Your heat pump is not working or broken.
The outdoor unit is completely frozen and cannot defrost itself.
Temperatures are extremely low, and the heat pump cannot keep up.
A technician has advised you to use it until repairs are made.

In most cases, if your heat pump is working, you should not switch to Emergency Heat manually. Let the system operate normally for the best energy savings.

How Long Can You Use EM Heat?

Another important aspect of em heat meaning is understanding duration. Emergency Heat is designed for short-term use only. If you leave it on for several days without fixing the heat pump, you could face very high energy bills. Ideally, Emergency Heat should only stay active until a technician repairs your system or the outdoor temperatures rise.

Running Emergency Heat for a few hours to a day is usually acceptable. However, if you need it for longer, ensure you monitor your electricity usage carefully.

Differences Between EM Heat and Auxiliary Heat

Many people confuse Emergency Heat with Auxiliary Heat. Both play important roles in your heating system, but their purposes are slightly different.

Aspect	Auxiliary Heat	Emergency Heat
Activation	Automatic	Manual or automatic
Purpose	Helps heat pump in very cold weather	Backup when heat pump fails
Typical Heating Source	Same as Emergency Heat	Same as Auxiliary Heat
Cost	Higher than heat pump, but necessary	Very high, for emergencies only

Auxiliary Heat supports your heat pump when it struggles but is not completely disabled. Emergency Heat is your last resort when the system cannot operate at all.

Why EM Heat Is Expensive

Understanding the em heat meaning also requires knowing why it costs so much. Heat pumps are energy efficient because they move existing heat rather than generating it. Emergency Heat, on the other hand, creates heat using electrical resistance, which requires a lot of energy.

Electric resistance heating is one of the least efficient heating methods available. If you run it constantly, your energy bill could double or even triple. Gas furnaces used in Emergency Heat setups are usually more efficient than electric coils but still cost more than a working heat pump.

Common Mistakes Homeowners Make With EM Heat

Not knowing the correct em heat meaning leads many homeowners to misuse it. Some common mistakes include:

Manually switching to Emergency Heat during mild cold days.
Forgetting to turn it off after the heat pump is repaired.
Assuming Emergency Heat will heat the home faster.

Emergency Heat does not make your home heat faster than the regular system. It only provides a different source of heat when the outdoor unit fails.

How to Know If Your EM Heat Is On

Most modern thermostats have an indicator light that turns on when Emergency Heat is active. You might also notice that your outdoor unit stops running, while your indoor fan continues blowing warm air. If you see higher electricity usage on your bills, that’s another clue that Emergency Heat has been running.

Always keep an eye on your thermostat to ensure you’re not unknowingly wasting energy.

How to Properly Use EM Heat

When it comes to using Emergency Heat correctly, understanding em heat meaning can save you a lot of money and stress. Follow these simple steps:

Only activate Emergency Heat if your heat pump is malfunctioning.
Contact a professional technician immediately after switching to Emergency Heat.
Turn Emergency Heat off once the primary system is repaired.
Monitor your thermostat settings daily during extreme weather events.

By using Emergency Heat correctly, you ensure your home stays warm without unnecessary costs.

The Role of EM Heat Meaning in Different Climates

In moderate climates, the need for Emergency Heat is rare. However, in colder regions where temperatures often drop below freezing, knowing em heat meaning becomes very important.

If you live in a southern state like Florida, you might never need Emergency Heat. But in northern states like Minnesota, it could be critical during deep winter months.

Here’s a quick table summarizing usage by climate:

Climate	Need for EM Heat
Mild (South US)	Rarely needed
Moderate (Midwest)	Occasionally during cold snaps
Severe (North US)	Frequently during winter storms

Frequently Asked Questions

What does EM heat mean on my thermostat?

EM Heat on your thermostat stands for Emergency Heat. It activates a backup heat source when your heat pump cannot work properly.

When should I use EM heat?

You should only use EM Heat if your heat pump is broken, not keeping up in extreme cold, or if a technician advises you to switch it on.

Is EM heat more expensive to run?

Yes, EM Heat is much more expensive than regular heat pump operation because it uses electric coils or gas to generate heat directly.

What happens if I leave EM heat on all the time?

Leaving EM Heat on all the time will cause your energy bills to rise sharply. It should be used only for short-term emergencies.

Conclusion

Now that you fully understand the em heat meaning, you can make smarter decisions about your heating system. Emergency Heat is an important backup feature designed to keep you safe and warm during extreme conditions or system failures.

However, it is expensive and should be used carefully. Always remember to consult a professional if you are unsure about whether you should switch to Emergency Heat.

In the end, the proper use of Emergency Heat ensures not only comfort but also helps you avoid high energy bills. Whenever you see that “EM Heat” light on your thermostat, you will now know exactly what it means — and what you should do next.