A typical heat pump reaches its balance point at about 26°F to 32°F, according to the U.S. Department of Energy. Below that, your home loses heat faster than the unit can supply it. In Fort Worth, a heat pump paired with a gas furnace (a dual-fuel system) is the practical way to stay warm through freezes like the one in February 2021.
What is a heat pump's balance point?
The U.S. Department of Energy's Building Science Education program defines the balance point as the temperature at which heating demand exceeds the heat pump's capacity. Above it, the heat pump carries the house alone. Below it, something else has to help.
The Department of Energy puts the typical heating balance point at roughly 26°F to 32°F. Your own number shifts with the unit's size and how much heat your house loses.
The Department of Energy's Building America program notes that supplemental heat on a standard heat pump is often held off by an outdoor-lockout thermostat above the balance point, which it says is usually 25°F to 40°F depending on climate.
How cold can a cold-climate heat pump go?
ENERGY STAR certification for air-source heat pumps includes third-party-verified performance testing down to 5°F. ENERGY STAR also says certified cold-climate models can keep operating below 5°F, though backup heat can be more efficient at lower temperatures.
Each model has its own lowest operating temperature. Ask for the manufacturer's rated limit and its low-temperature performance data for the exact model you are considering, not a general claim about the category.
| Heat pump type | Cold-weather reference point | What it means for you |
|---|---|---|
| Typical heat pump | Balance point near 26°F to 32°F | Below this, you need backup heat to keep up |
| ENERGY STAR cold-climate heat pump | Tested to 5°F, can operate below | Handles more of the winter on its own, but backup can still be more efficient in deep cold |
| Dual-fuel system | Switches to the furnace below a set temperature | Gas takes over in severe freezes |
Why does Fort Worth need to plan for deep cold?
Most Fort Worth winter days are mild, but the extremes are what test your system. The National Weather Service recorded a DFW minimum of -2°F on February 16, 2021.
The Texas Comptroller reported 139 consecutive hours at or below freezing in DFW during Winter Storm Uri. That is almost six days when a heat pump below its balance point would be working at its limit.
ENERGY STAR advises choosing a heat pump suited to the local winter climate where temperatures regularly dip below freezing. For North Texas, that means asking how the system will behave on the coldest nights, not just on a 45°F morning.
How does a dual-fuel system work?
ENERGY STAR describes dual-fuel systems as a heat pump combined with a traditional gas or oil furnace, operated based on costs and environmental benefits. In a Fort Worth home, that means an electric heat pump plus a natural-gas furnace.
The Department of Energy's building science guidance says a dual-fuel control can switch automatically from the heat pump to the furnace below the balance point. It switches back when the outdoor temperature rises. You do not have to flip anything by hand.
A common strategy, described by the Department of Energy, is for the heat pump to run above a transition temperature and the natural-gas furnace below it.
What temperature should the system switch to gas?
The switchover setting is not fixed. The Department of Energy says the transition temperature materially affects a dual-fuel system's energy and emissions savings, so the number matters.
The most economical changeover depends on:
- The heat pump's capacity and efficiency (coefficient of performance)
- The furnace's efficiency
- Your gas price and your electricity price
- Duct losses
- How much heat your house loses
For reference, one Department of Energy example runs the heat pump at 14°F and above and uses backup heat below 14°F. A Department of Energy field study of cold-climate heat pumps found the natural-gas furnace was used more below 8°F, with observed compressor and furnace lockout temperatures near 5°F and 24°F. The study is on the Department of Energy's heat pump field validation page.
Treat these as examples, not a rule for your home. Have your installer set the changeover from your equipment and utility rates.
Do you need a gas furnace backup?
If your home already has a gas furnace, you likely have the hardest part done. The Department of Energy says a heat pump can be installed in a dual-fuel configuration with an existing or new central fossil-fuel furnace. That makes a heat pump add-on a realistic option for many homes with a working furnace.
If you are replacing equipment, AC installation is the time to ask for a dual-fuel setup. If your furnace is older, a furnace repair check can show whether it is ready to be your cold-weather backup.
A licensed installer can also tell you which utility rebates from Oncor and Atmos may apply, as of November 2026.
What should you do before winter storm season?
- Ask your installer what your system's balance point and switchover temperature are set to.
- Confirm the furnace fires when the control calls for it.
- Check that the thermostat and outdoor sensor are working so the switch happens automatically.
- Raise the thermostat in small steps. The Department of Energy notes electric resistance backup can run at inappropriate times, including after you raise the thermostat by 2°F or more.
Frequently asked questions
Quick answers are in the FAQ below. If you want a licensed local company to look at your system, the next step is simple.
Call (817) 420-7026 or send a request to be connected with a licensed local heating and air company. Air Conditioning Repair Fort Worth is a free referral service and does not perform the work itself.
