The emergency heat setting on a heat pump thermostat is a backup system that provides heat when the heat pump fails or the coils ice over. It is different from auxiliary heat, which automatically turns on when the room temperature remains consistently lower than the set temperature. Emergency heat must be turned on and off manually and usually consists of electric heating elements or can be powered by natural gas or oil.
Understanding the Emergency Heat Setting
When the emergency heat mode is selected, the heat pump compressor shuts down, and the backup system takes over, generating heat from an electric heating element or a gas or oil source, not from heat transferred from outdoors. The blower in the air handler keeps working normally, making the heating system function like a furnace. The system will stay in EM heat mode until manually switched off.
Differences between Emergency Heat and Auxiliary Heat
- Activation: Emergency heat must be manually turned on, while auxiliary heat activates automatically when the room temperature drops below the set point.
- Heat Source: Emergency heat uses a backup heating source, such as electric, gas, or oil, while auxiliary heat utilizes the heat pump’s compressor.
- Efficiency: Emergency heat is less efficient than the heat pump’s normal operation, resulting in higher energy costs.
- Intended Use: Emergency heat is meant for short-term use during heat pump failures or icing issues, while auxiliary heat is designed for longer-term supplemental heating.
When to Use Emergency Heat
Using emergency heat is dramatically higher than normal, and it is not meant to run the way that the regular heat setting does. It is especially not meant to run all winter months. Overusing emergency heat can result in increased energy costs and can be harder on the HVAC unit, leading to costly repairs. Therefore, it is important to only run emergency heat for a short amount of time and to use it only in emergency situations when the primary heating system has failed or is unable to function properly.
Situations When to Use Emergency Heat
- Heat Pump Failure: If the heat pump compressor or other critical components fail, the emergency heat setting can provide temporary heating until the heat pump is repaired.
- Coil Icing: When the outdoor coil of the heat pump becomes heavily iced, the emergency heat setting can be used to melt the ice and restore normal heat pump operation.
- Extreme Cold Conditions: In some very cold climates, the heat pump may struggle to extract enough heat from the outdoor air, and the emergency heat can supplement the heating capacity.
Potential Drawbacks of Overusing Emergency Heat
- Higher Energy Costs: Emergency heat is typically less efficient than the heat pump’s normal operation, resulting in significantly higher energy bills.
- Increased Wear and Tear: Prolonged use of emergency heat can put additional strain on the HVAC system, leading to more frequent maintenance and potential breakdowns.
- Reduced Comfort: The emergency heat setting may not provide the same level of comfort and temperature control as the heat pump’s normal operation.
Proper Use and Maintenance of the Emergency Heat Setting
To ensure the efficient and effective use of the emergency heat setting, it’s important to follow these guidelines:
- Use Emergency Heat Only When Necessary: Avoid running the emergency heat setting for extended periods, as it can be costly and detrimental to the HVAC system.
- Monitor the System: Regularly check the heat pump’s performance and be aware of any issues that may require the use of emergency heat.
- Maintain the HVAC System: Proper maintenance, including regular cleaning and inspections, can help prevent the need for emergency heat and extend the life of the HVAC system.
- Consult a Professional: If you’re unsure about the proper use of the emergency heat setting or have concerns about your HVAC system, it’s best to consult a qualified HVAC technician.
By understanding the purpose and proper use of the emergency heat setting on your heat pump thermostat, you can ensure efficient and cost-effective heating for your home, while also protecting the longevity of your HVAC system.