According to the US Department of Energy, heat pumps can save you money by reducing your electricity usage by as much as 75%. We know a good number of homes in the Ozarks rely on traditional gas furnaces, not heat pumps. But if you do have a heat pump, you’ve probably noticed that it struggles during cold snaps. Your system may be running longer, working harder, and fighting to keep your home comfortable.
Why Heat Pumps Lose Efficiency in the Cold
Heat pumps don’t generate heat like furnaces do. Instead, they extract heat from outdoor air and move it inside. When it’s 50°F outside, there’s plenty of heat to work with. However, when it drops to 20°F, not so much.
Most heat pumps start losing efficiency below 40°F. By around 25°F, they are still more efficient than electric resistance heat, but they have to work harder.
With these cooler temps, your heat pump pulls less heat from the air and uses more electricity. You’ll notice longer run times and higher bills.
What Auxiliary Heat Actually Does
When your heat pump can’t keep up, auxiliary heat kicks in. This is electric resistance heat, which is basically the same technology as a space heater.
Auxiliary heat works, but it’s expensive. This is often a reason why bills spike during extended cold weather. If you’re seeing unexpectedly high bills, our post on low energy bill habits can help you identify other ways to keep costs down.
Your system is designed to use auxiliary heat as backup, not primary heat. If the auxiliary heat is running constantly, something is probably wrong.
What’s Normal and What’s Not
Here’s what you should expect during cold weather:
Normal:
- Longer run times below freezing
- Occasional auxiliary heat during the coldest parts of the day
- Slightly higher bills during extended cold snaps
- Your outdoor unit running when it’s very cold
Not normal:
- Auxiliary heat running constantly
- The system never reaching your set temperature
- Ice buildup that doesn’t melt during defrost cycles
- Strange noises or the system shutting off repeatedly
If you’re seeing the “not normal” symptoms, call for service. It could be low refrigerant, a bad defrost sensor, or incorrect thermostat settings.
How to Help Your Heat Pump Perform Better
Don’t crank the thermostat. Sudden temperature changes force auxiliary heat to kick in. So just set it and leave it.
Change your filter regularly. Restricted airflow makes your system less efficient, especially in cold weather.
Consider a programmable thermostat. Modern thermostats can avoid aggressive setbacks that trigger unnecessary auxiliary heat.
Get annual maintenance. Get annual maintenance. Low refrigerant, dirty coils, or worn components make cold-weather performance worse. To avoid other common heating mistakes that cost money, read about 6 common debunked heating myths to protect your system’s performance.
When It Might Be Time for an Upgrade
If your heat pump is 10-15 years old and struggling, newer models are significantly better. Modern cold-climate heat pumps maintain efficiency down to 5°F or lower, meaning less auxiliary heat and lower bills.
If you have any questions about your HVAC system, please get in touch with us today.