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How To Turn Off Auxiliary (Emergency) Heat On Any Thermostat [Detailed Guide]

Your HVAC system most probably has an integrated emergency heat and/or an auxiliary heat system. It is always good to have an emergency heat system in place for when the main system encounters any problems. And an auxiliary heat system ensures that your home always has a comfortable temperature – even during the cold winter months. 

But emergency/auxiliary heat systems can be costly and you may wonder whether it is possible to turn off the systems if you don’t need them.

Most thermostats make it possible for the user to turn the emergency/auxiliary systems off. Although the process of turning the systems off in principle follows the same pattern, there are differences in the sequence the steps have to be taken with each brand and even model.  

In this article, we’ll discuss some general steps and then also the specific steps to be taken when you have one of the commonly used thermostats. If you know the difference between emergency heat and auxiliary heat and understand how these systems work, you can skip the first few paragraphs and directly go to the section “How to turn off auxiliary heat and emergency heat.”

For those of you that don’t have the basic knowledge, we’ll start with a short discussion about emergency and auxiliary systems. 

What is the main difference between “auxiliary” and “emergency” heat?

Many people use “auxiliary heat” and “emergency heat” as synonyms for a feature offered in many HVAC systems. They are, however, two different concepts. 

In principle, the main difference between the functioning of the auxiliary and emergency heat systems is that;

  • auxiliary heat is backup heat that turns on automatically, and
  • emergency heat is what it says – emergency heat – to be switched on manually when needed. 

Auxiliary heat helps the compressor of the main system in stage 1 of the heating process to maintain the temperature setting. Both the auxiliary heat and the compressor are normally on simultaneously. 

Emergency heat has to be switched on manually. The thermostat will only activate the emergency heat function when the thermostat’s system switch has been manually moved to the “Em Ht” position. When emergency heat is on, the compressor does not run. 

Emergency heat and auxiliary heat often use the same source of heat. Generally, this source is electric heat strips or fossil fuel.

More about auxiliary heat and emergency heat

Auxiliary heat

To heat your home quickly or to maintain the temperature in your home on a comfortable pre-set level your normal heating source sometimes needs assistance. The thermostat then turns on the auxiliary heating function automatically to help the main system. 

The HVAC thermostat will automatically turn on auxiliary heat when heat can no longer efficiently be transferred from the outside air to the heat pump. This normally happens when the outside temperature is around 35 to 40 degrees and the home’s temperature is around three degrees cooler than the thermostat setting. The thermostat senses this and then automatically turns on electric heat strips. This provides additional heat as needed for as long as it is needed.

Emergency heat

Some heat pump systems include an emergency heat feature. You have to turn this on manually. Generally, you will turn it on only when the primary heating system isn’t working. But you might also turn it on if your HVAC system doesn’t have an auxiliary heat function to keep your home warm enough. This is not good practice – you should only use emergency heat when it is a real emergency. That means you use it only when your primary heating is down or the temperature is below 30 degrees.

Cost escalation – how to keep it low

Both these two features use electric resistance heating and this is not as efficient as your main heat pump. If your system stays in auxiliary heat or emergency heat mode when it is not needed, your energy bill will run up very quickly.  

While it is normally easy to turn off the emergency heat function when the emergency is over, it sometimes feels as if you can’t do much when the thermostat indicates that auxiliary heat is being used. 

Many homeowners just accept that in winter the auxiliary heat function will cause higher utility bills and you can’t do anything about it. But you can take some steps in this regard. You can actually stop the auxiliary heat from even turning on if you want to. 

In most instances, the auxiliary heat function kicks in because the temperature in the home is set too high. When you expect your furnace to work too hard to maintain a comfortable temperature, the outdoor heat pump might not be able to hold up. To provide the temperature you are expecting, assistance from the auxiliary heat system is needed.

To avoid the auxiliary heat system turning on automatically, the easiest is to lower the temperature in your home. If you set the thermostat for sixty to sixty-eight degrees, your auxiliary heat will not be turned on automatically.  

If you then feel the temperature is too cold you can snuggle under a cozy blanket! You can perhaps use your oven to do some holiday baking – the heat of the oven will heat the kitchen. The heat from your laundry dryer will also bring some heat into your home. Good insulation will help to keep the temperature in your home comfortable without the need for the auxiliary heat system to kick in. 

How to turn off auxiliary heat and emergency heat: General methods that might work for all brands

There are generic ways to turn emergency heat or auxiliary heat off. Before we look at specific brands and models, let’s look at two easy procedures that might turn the features off regardless of what brand it is. 

How to turn off Emergency heat

The simplest way to turn off the emergency heat feature is to switch it off manually. There are no devices involved that will put it on automatically. So, you have to put it on manually and you put it off again manually.

How to turn off Auxiliary heat

If you have a heat pump, the thermostat normally turns the auxiliary heat on when the heat setting increases by 3 or more degrees. Thus, a good idea is to increase your heat setting by only two degrees at a time. This normally prevents your auxiliary heat from operating.

Nest Thermostats

Turn off emergency heat

You can turn the emergency heat off with either your home app or on the Nest thermostat.

With the home app

You have to open the home app and tap your thermostat.

Then tap “Settings,” followed by “Thermostat,” and then “Emergency Heat”

Finally, tap the switch to turn it on or off.

On your thermostat

  • Go to “Settings” on your Nest thermostat, and then to “Emergency Heat.”
  • Select “Continue” and “Yes” to turn the emergency heat on. 
  • If the system is already using emergency heat and you want to turn it off, select “Turn off.”

Turn off auxiliary heat 

You can also turn the auxiliary heat function off via your Google Home app.  Tap on “Settings,” followed by “Thermostat,” and “Auxiliary Heat.” And then tap the switch to turn it off.

But always remember that before you turn it off ensure you don’t need it for defrosting or continuous heat anymore. It is recommended by the manufacturer that you only turn it off manually if it’s not cold outside or it’s been on for more than 10 to 15 minutes.

Honeywell thermostats 

You can either turn the auxiliary heat function off “permanently” so that your Honeywell thermostat will never be able to activate the auxiliary heat system, or you can turn it off only when it has been turned on and you don’t need the auxiliary heat at that stage.

Turn the auxiliary heat off “permanently” 

There are two ways to “permanently” prevent the Auxiliary Heat from turning on. 

Change the system designation configuration

Have a look at your Honeywell thermostat’s installation instructions and follow the steps on how to get to the settings to change the system’s designation.  Then change the thermostat’s designation to “1 heat, 1 cool heat pump.” By using these designations the thermostat cannot detect any system providing auxiliary heat and thus, cannot turn it on.

Disconnect the wire

Take your Honeywell thermostat from the wall by using a small screwdriver, and pull the wire off the “W” terminal. This signals to the thermostat that there is no auxiliary heat system available to activate. 

Reverse the “permanent” disabling of the auxiliary heat system

If you at a later stage wish to make the auxiliary heat feature part of the system again, you have to reverse the steps you’ve taken to deactivate the system. So, if you’ve followed the changing of designation route, you have to change the designation back to “normal.”

If you’ve disconnected the wire, take the thermostat from the wall again and connect the loose wire to the “W”-wire. 

Turn the auxiliary heat off on the thermostat when not needed

You can turn off the auxiliary heat feature on your Honeywell thermostat by setting the temperature at 70 degrees. If you then set the required temperature between 60 and 80 degrees you’ll keep your house at a regular temperature without the thermostat activating the auxiliary heat system. 

If you are living in an area where you experience very cold winters, it is recommended that you don’t “permanently” disable the auxiliary heat system. It is still less expensive to use auxiliary heat when necessary than to activate your emergency heat system to help your main system to get your home’s temperature on a comfortable level.

Ecobee thermostats

Ecobee’s warning system

Ecobee offers a unique service to Ecobee thermostat users. They inform Ecobee thermostat users on their mobile devices when their HVAC systems are using auxiliary heat. You will receive an alert from Ecobee during the winter months, informing you that the auxiliary heat system has been on for a longer period than can normally be expected. The warning will indicate the pattern of the periods (in minutes and hours) when the auxiliary heat has been active within a day. 

When you’ve received such a message you can adjust the threshold settings to make the auxiliary heat system run less during a day.

How to turn the auxiliary heat off 

To turn off the auxiliary heat function on the Ecobee thermostat is simple and easy: 

  1. Select “Main Menu,” then “Settings,” and then “Preferences.
  2. Select either “Heating Recovery” or “Cooling Recovery.”
  3. Touch “Disable”

Alternatively;

  1. Go to “Main Menu”, then “Settings”
  2. Select “Installation Settings” and go to “Thresholds”
  3. Select “Aux Heat Max Outdoor Temperature” and lower the temperature set there.

The auxiliary heat won’t turn on when the outside temperature is greater than the one set. You can set this to any lower values and thus stop the aux heat from turning on.

How to turn off Emergency heat on Carrier Thermostats

The Carrier heat pump systems sometimes use emergency heat when the automatic auxiliary heat system is not able to keep up with the demand, or the heat pump compressor that works with auxiliary heat has failed. You can turn on the emergency heat to assist the main system. 

But normally, you want to avoid using emergency heat, because it’s a very expensive option. To either turn emergency heat on or off, on your Carrier thermostat just follow the two easy steps:

  • Press the mode button repeatedly until you see “Em heat” in the upper left of the display. 
  • To turn off emergency heat, you have to press the mode button again to select “heat,” “cool” or “auto.”

Trane Thermostats

Turn off Emergency Heat

You can disable or enable the emergency heat function on your Trane thermostat. A small “e” will indicate on the thermostat if the system is using emergency heat. When you look at the interface to find a setting to manually put it on or off, you will not find such setting options. To get to the options to either enable or disable the use of emergency heat, click on “System options” at the left bottom of the thermostat. You will now get to an interface showing “Emergency Heat.” with the options to enable or disable it. 

If the emergency heat feature has accidentally been turned on without the main system actually needing any emergency heat, you can just click on “Disable” and the thermostat will turn off the emergency heat system. When you’ve manually turned on the emergency heat system because of a fault in the main system, you follow the same procedure to turn it off again when the fault has been repaired. There are videos available to show this procedure step by step. 

Turn off Auxiliary Heat

Unfortunately, it seems as if there is no possibility to decrease the sensitivity of the Trane manual thermostats so that the auxiliary heat system would not come on so often. However, some high-end electronic ones may let you adjust the differential of the auxiliary heat system separately from the regular heat. The way to do it differs from model to model. You’ll have to follow the steps given in the applicable manual or online videos and guides.