Heat pumps offer an energy-efficient solution for both heating and cooling, especially in areas with mild winters like Visalia, CA. Many homeowners notice their thermostat display “AUX HEAT” during colder mornings. This auxiliary heat function is an important—but often misunderstood—part of heat pump operation. Understanding how it works helps maintain comfort, efficiency, and proper system performance.
What Is Heat Pump Auxiliary Heat?
Auxiliary heat, also known as “backup heat,” is a secondary heating source designed to support your heat pump when outdoor temperatures drop and the primary system can’t keep up. In Visalia, heat pumps typically operate efficiently, but on unusually cold nights—when temperatures dip into the 30s—the system may struggle to extract enough warmth from the outdoor air. When this happens, the electric resistance coils inside your air handler automatically activate to maintain your indoor temperature.
If you recently had an air conditioning installation service, your installer likely included these heat strips for extra reliability during seasonal cold snaps.
When and Why Does Aux Heat Activate?
Your thermostat is programmed to detect when your heat pump needs support. Common triggers include:
- Large, sudden increases in thermostat settings
- Outdoor temperatures falling below 35-40°F
- Defrost cycles, when frost forms on the outdoor coils
- Poor insulation or underlying system issues
In many cases, frequent aux heat activation can indicate the need for air conditioning maintenance, especially if temperatures are mild.
Auxiliary Heat vs. Emergency Heat: What’s the Difference?
Auxiliary heat turns on automatically when needed.
Emergency heat, however, is a manual setting used only when the heat pump’s outdoor unit is malfunctioning or shut down. This mode relies solely on the electric heat strips and uses significantly more energy.
If you’ve ever had to switch to emergency heat, it’s a clear sign your system needs prompt air conditioning repair.
The Cost and Efficiency Impact of Auxiliary Heat
Aux heat is helpful but comes with a cost—electric resistance heating uses far more electricity than standard heat pump operation. To reduce unnecessary aux heat usage:
- Increase your thermostat setting gradually
- Improve insulation and reduce air leaks
- Replace air filters regularly
- Schedule routine professional tune-ups
Homeowners in the area often find that with proper maintenance, aux heat is needed only occasionally, helping prevent high utility bills.
Troubleshooting and Maintenance Tips
If your system frequently switches to auxiliary heat—even during mild weather—possible causes include:
- Dirty or clogged air filters
- Blocked outdoor coils
- Incorrect thermostat programming
- Low refrigerant or heat pump malfunctions
Professional maintenance can resolve these issues quickly and restore efficient heating.
Stay Comfortable—Call Your Local HVAC Team
If you’re in Visalia, CA and have questions about your heat pump’s auxiliary heat function—or if you need reliable air conditioning repair, air conditioning maintenance, or air conditioning installation—Superior Air is here to help. Our experienced technicians can diagnose system issues, improve efficiency, and ensure your home stays comfortable all winter long. Give us a call at (559) 734-2002 or fill out our online form to get started.
