Nest Aux Heat Vs Emergency Heat

Customers have found Nest thermostats user-friendly, environmentally friendly, and even budget-friendly! There are a lot of questions concerning Google’s new Nest thermostat, but before we answer them, you want to know what “Aux Heat” means and how to turn it off. Here is a complete comparison of Nest Aux Heat Vs Emergency Heat.

You may notice that the Nest thermostat displays “Aux Heat” instead of “Heat” when you’re warming your house, which indicates that your heat pump is using a supplementary heating source to keep your room warm in severely cold weather.

Here, we’ll explain how your Nest thermostat works with your heat pump and how to fix the Nest itself if that pesky “Aux Heat” indicator won’t go away. ‘I want to make sure you know everything about the auxiliary heat your Nest warns you about (in one easy-to-read post).

Comparison Between Nest Aux Heat Vs Emergency Heat

What Is Emergency Heat?

If your home’s heating system goes out, emergency heat, or “EM heat,” is the setting that controls the backup heating system. A heat pump is the most common method of heating a home. When supplemental heating, such as that provided by gas, oil, or electricity, is required, the secondary heating system is typically turned on.

An additional heat source is required in colder regions for your home to be adequately heated. Your heat pump can’t get enough warmth from the outside air to keep your home at your target temperature in extreme temps. When the temperature drops, EM heat activates to provide additional heating.

There are two types of heating systems: “first-stage” heat pumps and “backup” heating systems. Your thermostat system will determine when emergency heating is engaged, as each system has a distinct technique of recognizing when emergency heat is needed to help with first-stage heating.

How does Emergency Heat Work?

When it’s below 40 degrees outside, your HVAC system will need to defrost cycles many times an hour to keep working. However, your heat pump may not be able to create any heat if the ambient air temperature is in the 20s or 30s or below since there is not enough to extract.

It gets so cold outside that compressing refrigerant becomes practically impossible, and as a result, what little heat is left cannot be absorbed. You need to turn off the heater since using it in these conditions could cause serious harm to it.

For situations like this, the heater’s “emergency” setting is there. Your system’s radiation heat strips are activated when the thermostat is turned on. This prevents damage to your external heat pump equipment and allows you to continue receiving heat. The term “emergency” has been applied to this since you’ll be putting in extra effort, so keep that in mind. To prevent damage to your core system, only use this mode when necessary.

What Does Aux Heat Mean?

The backup heating system of your heat pump, also known as electric resistance heating, is referred to as “auxiliary heat” on your thermostat. The supplemental heat is activated based on the temperature set in your home’s thermostat.

Depending on whether your home has a Honeywell, Nest, or another smart thermostat, the aux heat indicator on your thermostat will illuminate or begin flashing for some time to let you know when this occurs.

For this reason, whenever the temperature dips below your thermostat’s programmed temperature, your thermostat activates supplemental heat. When the temperature on your thermostat drops 2-3 degrees below the set temperature for your indoor climate, this is a regular occurrence. Aux heat will be turned off when your home’s temperature is set to the desired level.

How does Auxiliary Heat work?

To keep your home warm, your system automatically switches on the radiation strips when it reverses to defrost the coils. Running on “auxiliary heat” is the term for this. When your system senses that it has been running for too long or that too much ice has built upon the outdoor coil and needs to begin a defrost cycle, it switches to automated mode.

Comparison Between Auxiliary Heat vs Emergency Heat

As a result, what is the difference between auxiliary and emergency heat, and how are they different? If you live in an area where temperatures fall below freezing, you’ll need an auxiliary heating system to warm your home. If the temperature unexpectedly lowers, auxiliary heating kicks in to keep your home warm.

A backup heating source is needed for heat pumps. When the temperature dips below 40 degrees Fahrenheit, this is very important. Heating sources such as this electric resistance heating can be used to supplement the unit’s heating system. Gas, oil, and even hot water backup systems can be included.

“second-stage” or “backup” heating refers to these additional heating sources. The heat pump is the “initial state” heater. Using only your “second stage” without turning on your “first stage” is what we mean by “emergency heat.”


That’s everything about Nest Aux Heat Vs Emergency Heat. For the most part, Nest devices don’t send out AUX heat warnings for no cause. If your heating system has an AUX heat function, you must configure it to meet your unique needs and preferences.

Using Nest Sense, you’ll have complete control over your home’s heating and cooling systems. You may turn on the auxiliary heat all winter long, with the only exception being an unforeseen problem with the heating system.

Frequently Asked Questions

Is emergency heat the same as auxiliary heat?

Auxiliary Heat – This is a backup heat source that automatically switches on. When you switch on the secondary heat source in an emergency, it is called “emergency heat.”

Why does Nest utilize aux heat?

AUX heat can be used by your system to keep you warm in cold weather or modify your home’s temperature swiftly. Heat pumps are more energy-efficient than most conventional heating systems, but they take longer to heat your home as the weather grows colder.

Is it normal for my heat to be set to AUX?

To begin, AUX heat refers to your heat pump’s auxiliary (backup) heat supply. When your heat pump isn’t producing enough heat to keep your home warm on its own, auxiliary heat kicks in; when the temperature outdoors is below freezing, AUX heat mode is usual.

Is it okay to use the heat pump as an emergency heat source?

The answer is a resounding Yes if you have an all-electric heat pump. Running your heat pump on Emergency Heat is substantially more expensive. And, as the name implies, it should only be used as a last resort until your heat pump is repaired.

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