What’s the Difference Between Auxiliary Heat and Emergency Heat?
Understanding Your Heat Pump Settings This Winter
As temperatures drop here in the Tri-Cities—whether you’re in Johnson City, Kingsport, Bristol, or the surrounding areas—your HVAC system works hard to keep your home warm and cozy. If you rely on a heat pump for heating, you may have noticed settings like “Aux Heat” or “Emergency Heat” on your thermostat. But what do these terms mean, and how are they different?
At Air Comfort Services, we get this question a lot from homeowners. Let’s break it down so you can understand how your heating system works and when to use each setting.
What is AUX Heat?
Auxiliary Heat (Aux Heat) is a backup heating system that works automatically when your heat pump needs extra help to maintain your desired indoor temperature.
Here’s how it works:
- Heat pumps pull heat from the outside air to warm your home. However, as temperatures drop below freezing (common in East Tennessee winters), your heat pump becomes less efficient.
- When this happens, your system activates Aux Heat, which uses electric resistance heating or a gas furnace (depending on your setup) to provide additional warmth.
- It turns on automatically—you don’t need to adjust anything on your thermostat.
? When is Aux Heat used?
- During extremely cold weather (below 35°F).
- If the heat pump can’t keep up with sudden temperature drops.
- When you manually increase your thermostat setting by several degrees (this triggers Aux Heat to speed up the process).
What is EMER Heat?
Emergency Heat is a manual setting on your thermostat that bypasses the heat pump entirely and uses only the backup heat source to warm your home.
Think of Emergency Heat as a “Plan B”—it’s meant for situations when your heat pump is malfunctioning or unable to work properly.
? When should you use Emergency Heat?
- If your heat pump has stopped working (e.g., frozen coils, a mechanical issue, or damage).
- If there’s a major ice storm or extreme weather event that prevents the heat pump from pulling in heat.
- If your HVAC technician advises you to switch to Emergency Heat until repairs are made.
?? Important Note: Emergency Heat can be significantly more expensive to run because it relies solely on electric resistance heating or a secondary heat source. Use this setting sparingly!
Key Differences Between Aux Heat and Emergency Heat
| Feature | Aux Heat | Emergency Heat |
|---|---|---|
| Activation | Automatic | Manual (you must switch it on) |
| Purpose | Supports the heat pump | Bypasses the heat pump entirely |
| When Used | During cold weather | When the heat pump is broken |
| Cost to Operate | Moderate | Higher due to backup heat source |
What Should You Do If Emergency Heat Kicks In?
If your system switches to Emergency Heat, it could signal a problem with your heat pump. Here’s what to do:
- Check your thermostat. Verify the setting and look for alerts.
- Inspect the outdoor unit. Make sure it’s not covered in ice or blocked by debris.
- Call a professional HVAC technician at Air Comfort Services for a thorough inspection and repair.
Keep Your Heat Pump Running Efficiently This Winter
To avoid unexpected switches to Aux Heat or Emergency Heat, follow these tips:
- Schedule a seasonal HVAC maintenance check-up to ensure your heat pump is in top shape.
- Replace your air filters regularly to improve airflow and efficiency.
- Keep your thermostat settings steady—frequent adjustments can trigger Aux Heat unnecessarily.
Trust Air Comfort Services for Reliable HVAC Solutions
At Air Comfort Services, we’ve been serving the Tri-Cities area for over 20 years. Whether you need routine maintenance, emergency repairs, or answers to your HVAC questions, our team is here to help.
Don’t let a heating issue disrupt your comfort this winter. Call us today at (423) 677-7856 or schedule service online!
? Proudly Serving Johnson City, Kingsport, Bristol, Elizabethton, Gray, and surrounding areas.
Ready to keep your home warm and cozy this season?
Contact Air Comfort Services today—your comfort is our priority!