A Simple Guide for Homeowners in Northwest Georgia
When temperatures drop into the teens and 20s here in Cartersville and across northwest Georgia, we start getting the same question every winter:
- Why does my thermostat say AUX heat?
- Is something wrong with my heat pump?
- Why did my power bill jump?
If you’re seeing AUX HEAT or EM HEAT on your thermostat, don’t panic. Most of the time, it’s completely normal.
Here’s an easy, homeowner-friendly explanation from your local team at Weaver Heating and Air.
First — What Is Auxiliary Heat?
Think of your heating system like this:
- Your heat pump = the main heater
- Auxiliary heat = the backup helper
A heat pump normally pulls heat from the outside air and moves it inside your home.
But when it gets really cold outside, there isn’t much heat available to pull from the air.
So your system calls in backup heat (called auxiliary heat) to help out.
In plain English:
Aux heat is just your system’s “extra muscle” for cold weather.
Why Does AUX Heat Turn On?
Here are the most common (and normal) reasons:
1. It’s Really Cold Outside
When temperatures drop below about 30–35°F, heat pumps lose efficiency.
Your system basically says:
“Hey, I need help keeping up!”
Auxiliary heat turns on to boost warmth faster.
Totally normal during:
- Cold snaps
- Overnight freezes
- Early mornings
- Ice storms
2. You Raised the Thermostat Several Degrees
If you bump your thermostat from:
68° → 73°
Your system thinks:
“Whoa, we need heat FAST!”
So it kicks on auxiliary heat to warm the house quicker.
Tip: Raise temperatures slowly (1–2 degrees at a time) to avoid triggering aux heat unnecessarily.
3. Defrost Mode
If you have a heat pump, you may notice steam or frost outside sometimes.
During defrost cycles:
- The outdoor unit briefly switches modes
- Aux heat turns on inside so you don’t feel cold air
Again — normal operation.
What Exactly Is Auxiliary Heat?
Inside your indoor unit are electric heat strips.
They work kind of like:
- A toaster
- A space heater
Pros:
- Heats quickly
- Great backup
- Keeps you comfortable in extreme cold
Cons:
- Uses more electricity than a heat pump
That’s why your power bill can go up during very cold weeks.
When Should You Worry?
Auxiliary heat is normal.
But constant AUX heat all day long isn’t.
Call for service if:
- AUX heat never turns off
- Your house won’t reach the set temperature
- The system is blowing cool air
- The system runs nonstop
- Your power bill spikes during mild weather
These issues can point to:
- Dirty air filter
- Refrigerant issues
- Frozen outdoor unit
- Heat pump not working properly
- A system that needs maintenance
How to Reduce Auxiliary Heat Use
Here are some easy homeowner tips:
- Change your air filter regularly
Dirty filters restrict airflow and make systems work harder. - Don’t make big thermostat jumps
Increase temperatures gradually. - Keep the outdoor unit clear
Remove leaves, snow, and ice buildup. - Schedule seasonal maintenance
A tuned system runs more efficiently and needs aux heat less often.
Quick Summary
If you remember nothing else, remember this:
- Aux heat does not mean your system is broken
- It simply helps when it’s really cold
- It’s normal in Georgia winters
Your HVAC system is basically saying:
“I’ve got you — let’s stay warm.”
Need Help or Have Questions?
If your system seems to be running auxiliary heat more than it should, our local team is always happy to check things out and make sure everything’s working efficiently.
We live and work right here in Bartow County, so we know exactly how these cold snaps hit our homes.
Stay warm,
Weaver Heating and Air Team
