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The “EMER” feature on your thermostat is engineered to autonomously control your emergency heating system.

This is useful in several scenarios, especially when your heat pump or first-stage heating equipment is malfunctioning or frozen over. 

So in this guide, I’ll show you how to enable this setting and how to use it effectively. 

What is “EMER” or Emergency in Your Thermostat?

The “EMER” on your thermostat stands for Emergency Heat.

This is a backup mode designed to kick in when the primary heating system fails or is unable to handle extremely cold temperatures.

This setting engages a secondary heating source, such as an electric heating strip or gas furnace, allowing your house to stay warm even when the conditions outside are less than ideal.

However, Emergency Heat isn't the most energy-efficient setting since it's designed for use as a backup, and not a primary source of heat.

So if engaged unnecessarily, it can drive up your energy bills.

Emergency Heat Vs Auxiliary Heat

For White Rodgers thermostats, the Emergency heat setting and auxiliary heat setting call for the same heating generator to turn on.

However, in other brands and systems, there is the option to configure completely two different heating equipment for the auxiliary and emergency.

Auxiliary Heat

For thermostats, auxiliary heat stands for the emergency heat source that’s controlled by the thermostat automatically and switches on when the outside temperatures are too low for the heat pump to manage.

Thermostats can use outdoor temperature sensors, but the majority of models simply count down how long it takes for the heat pump to warm up your home. 

So if it calculates that the heat pump is inefficient (such as taking more than half an hour to increase the temperature by a couple of degrees), it will switch on the auxiliary setting. 

Emergency Heat

Meanwhile, emergency heat is the setting that the user can switch on manually. 

For the majority of systems out there, both auxiliary heat and emergency heat settings control the same piece of heating equipment.

When to Use Emergency Heat? 

While it is good to understand the purpose of the “EMER” or “Aux” setting, you must put off using it unless absolutely necessary.

This secondary heat source, such as the electric heating strip or gas furnace, can draw up a lot of power. Besides, they aren’t meant to run continuously and tend to wear down faster. 

So, you should only toggle the emergency heat setting if the HVAC equipment is down and you want to keep the house warm until an HVAC company can come and take a look.

Which Systems Come with an Emergency Heat?

Typically, systems with a heat pump as the primary source of heating and cooling will include emergency heating equipment. 

Emergency/auxiliary heating equipment is an important component in heat pump systems where the temperature can go beyond 35 degrees Fahrenheit (1.67 degrees Celsius). 

Configuration Menu

In certain models, the option to switch to Aux Heat or Emergency Heat will not be displayed. 

To make sure this is available and functional, you have to configure your system for a heat pump and auxiliary heating equipment in the equipment configuration menu. 

So in the equipment configuration menu, you will have to set the: 

  • Outdoor equipment to HP1 or HP2 (Heat Pump Single Stage or Heat Pump 2 Stage)
  • And Indoor equipment to EL or GA (Electric or Gas)

To learn how to access the equipment configuration menu on your specific model, make sure to check the list of user guides here. 

How to Toggle the Emergency Heat in a White Rodgers Thermostat?

In the sections that follow, I'll show you how to toggle the emergency setting on your White Rodgers thermostat. 

You can scroll down and find instructions for your specific model, or you can check out this guide to learn how to identify your model number and take a look at the user manuals. 

Sensi App

iOS and Android app for controlling Sensi Smart thermostats

Sensi App Logo

You can easily toggle the emergency heat system mode using the Sensi app if you have a Sensi smart thermostat installed and configured. 

To toggle the system mode to Emergency Heat in your Sensi thermostat:

  1. Launch the Sensi App and pick your thermostat.
  2. Press the Mode button, which is located at the bottom left of the app's home screen. This button usually displays the current system mode, whether that’s “Heat”, “Cool”, or “Auto”.
  3. A quick list of options will open up. Here, tap on Aux Heat/Emergency Heat to activate it.

Your app will then switch to the emergency mode setting. However, don’t forget to take it out of the emergency heat mode after the temperatures improve. 

Sensi App system modes
Adjusting system modes via the Sensi app

Sensi Touch Smart

Smart thermostats with touchscreen

Sensi Touch Smart

On the thermostat’s home screen, you can press the mode button to list out the available system modes. Here, select “Aux Heat.”

Sensi Touch Smart System Mode
How to toggle the system modes in a Sensi Touch Smart thermostat

Please note that the emergency heat option will not be displayed unless the thermostat is configured to include one. 

Sensi Touch 2 Smart

Smart thermostat with touchscreen

Sensi Touch 2 Smart

The Fan and System settings button will be located at the mid-left of the touchscreen. This button will show the current system mode and color the fan if it’s turned on. 

  1. To adjust the system mode, simply tap on this button.
  2. A new menu will open up, indicating tiles for the available system modes and fan settings.
  3. Simply tap on “Aux” to enable the emergency heat. 
Sensi Touch 2 System Modes
Toggle system mode setting on a Sensi Touch 2 Smart

Sensi Lite Smart

Smart thermostat with touchscreen

Sensi Lite Smart 1
  1. Wake up the thermostat by pressing any of the buttons.
  2. After that, keep pressing the menu button to toggle between the available system modes. 
  3. Here, keep toggling until the display shows Aux Heat and its corresponding icon. 

If you don’t have the option to toggle Aux Heat, you will have to reconfigure the equipment. 

Sensi Smart Thermostat

Programmable thermostat with Wi-Fi for remote access

Sensi Smart Thermostat 1

The list of available system modes and the currently selected one will be highlighted on the thermostat’s home screen (at the bottom left right above the “Mode” button). 

To switch to the Aux Heat, you can simply press the Mode button to toggle to this setting.

Emerson Blue Series 12″ Touchscreen

Programmable thermostat with touchscreen

Blue Series 12 Emerson Touchscreen Thermostat 1

To enable the emergency heat on your Blue series 12” thermostat, simply tap on the System button to highlight the “Em” option. This will disable and clear out other options. 

Emerson Blue Series 12 Inch system modes
How to switch the system mode in an Emerson Blue 12″ Series

Emerson Blue Series 6″

Programmable and non-programmable thermostat models

Blue Series 6 Inch 1

When the system is configured for Aux Heat, you can enable this setting by pressing and holding the “Heat” button for five seconds. 

Then, the “Aux” section will fill up in the display (alongside “Heat” at the bottom) indicating the system is now calling for auxiliary heating. 

To disable Aux heat, simply press the heat button once. The “Aux” label will clear out.

6 Aux Heat
You can switch on the Aux Heat by holding the “Heat” button for five seconds

Emerson Blue Series 4″

Programmable and non-programmable thermostats

Blue Series 4 Inch 1

Press the button assigned to “System” to toggle between the different system modes. For emergency heating, you can keep toggling until the display shows: “Emer.”

Emerson Blue Series 2″

Programmable and Non-programmable thermostats

Blue Series 2 Inch 1 1

For this model, you have a physical switch that can toggle to the emergency heat system mode. 

So simply slide the toggle button to the “EMER” setting and adjust temperatures as desired. 

Blue Series 2 Inch System mode
Toggle the system switch to “EMER”

White Rodgers Classic 70/80 Series and Regular 70/80 Series

Programmable and Non-programmable thermostats

7080 Classic and regular

For the majority of this lineup, you have a physical toggle switch or a rotary dial that helps you switch between Aux Heat/Emer and the rest of the available system modes. 

These are:

  • 80 Series: 1F83H-21NP and 1F83H-21PR
  • 70 Series: 1F75H-21NP and 1F75H-21PR
  • Classic 80 Series: 1F82-261 and 1F89-211
  • Classic 70 Series: 1F72-151 and 1F79-111
Emergency heat 7080 c and regular
How to switch the Aux heat via the physical switches


The EMER or Aux Heat setting on a White Rodgers/Emerson thermostat can help the user manually bypass the heat pump and turn on the auxiliary heating equipment.

This emergency heating equipment can consume a lot of power; hence it is only recommended during emergencies.

So make sure to check the instructions of your model and note them down. However, only use this option sparingly. 


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