A standard air-source heat pump heats efficiently in mild and cool weather, but it starts losing heating capacity as temperatures drop into the 20s and 30s°F, and it leans on backup heat on the coldest days. Cold-climate heat pumps are different: manufacturers like Mitsubishi and Trane now rate their cold-climate models to deliver full heating capacity at 5°F and keep heating well below 0°F.
Air Comfort Technologies is a locally owned HVAC company in Manchester, PA, serving York County since 2015. Here's how heat pumps handle our winters, what happens when it gets really cold, and how to get the most out of yours.
How a Heat Pump Works
A heat pump doesn't burn fuel to make heat. It moves heat. In winter, it pulls heat out of the outdoor air, even cold air, and carries it inside using refrigerant. In summer, it runs in reverse and moves heat out of your home, just like an air conditioner.
Because it moves heat instead of creating it, a heat pump can deliver more heat energy than the electricity it uses. As the outdoor air gets colder, there's less heat to grab, so a standard heat pump has to work harder and puts out less heat.
Heat Pump Temperature Range: Standard vs. Cold-Climate
| Standard air-source heat pump | Cold-climate heat pump | |
|---|---|---|
| Full heating capacity | Down to roughly the upper 20s to 30s°F, depending on the model | Down to about 5°F on leading models |
| Below that | Capacity drops; backup heat helps more often | Still heating; capacity tapers slowly |
| Coldest operation | Many models are rated to operate around 0°F to -10°F, with reduced output | Down to about -13°F to -22°F, depending on the model |
| Examples | Trane standard variable-speed: about 100% capacity to ~27°F and ~70% at 5°F | Mitsubishi Hyper-Heat (H2i): 100% capacity at 5°F, rated heating to -13°F (ducted P-Series) or -22°F (select ductless models); Trane 20 Premiere Cold Climate: up to about 107% at 5°F |
Figures are manufacturer-published and vary by model, size, and the indoor unit it's paired with. We'll check the exact specs for any system we recommend.
York County's coldest winter nights typically dip into the single digits or low teens, so a cold-climate model can carry most homes through the entire winter with little or no backup heat.
What Happens When It Gets Too Cold?
When a heat pump can't keep up on its own, a few things help it out:
- Backup heat strips. Electric heat strips in the air handler turn on to add heat when the heat pump falls behind. They work well but cost more to run, so you want them to come on only when needed.
- Dual fuel with a gas furnace. A heat pump paired with a gas furnace uses the heat pump in mild weather and switches to the furnace when it gets cold. It's a popular setup in York County.
- Defrost mode. In cold, damp weather, frost builds up on the outdoor coil. The heat pump briefly switches into defrost to melt it. You may see steam rising from the outdoor unit. That's normal.
Ductless Mini-Split Heat Pumps in York County Winters
Ductless mini-splits have improved a lot. Today's cold-climate models, like Mitsubishi's Hyper-Heat line, keep heating strongly on the coldest York County nights. They're a great fit for:
- Additions, finished basements, and garages without ductwork.
- Third floors and bonus rooms that never stay comfortable.
- Homes with boilers or baseboard heat that want efficient heating plus central-style cooling.
Each indoor unit has its own control, so you can heat and cool only the rooms you're using. They're quiet, efficient, and install without major construction. Read more in our post on cooling the third floor.
Best Thermostat Setting for a Heat Pump in Winter
- Pick a comfortable setting, around 68°F, and leave it. Heat pumps work best with steady temperatures.
- Avoid big setbacks. Dropping the temperature a lot overnight and cranking it up in the morning can trigger backup heat, which costs more. Small setbacks of 1 to 2 degrees are fine.
- Use "Emergency Heat" only in an emergency, like when the outdoor unit isn't working. It runs on backup heat alone.
- Use a heat pump compatible smart thermostat that knows how to manage backup heat.
Is a Heat Pump Right for Your Home?
For many York County homes, yes, especially with a cold-climate model or a dual fuel setup. When we give you an estimate, we look at your home's size, insulation, ductwork, and current heating so we can recommend the right system. If you want the best cold-weather performance, ask us about a cold-climate model.
Heat pumps deliver cooler supply air than a gas furnace, so winter air can feel dry. The Aprilaire 800 steam humidifier pairs well with a heat pump. See our whole-house humidifier guide.
Install estimates are free, financing is available on new systems, and every install comes with a 5-year labor warranty. Learn more about heating installation, AC installation, or heating repair if your current heat pump isn't keeping up.
Frequently Asked Questions
At what temperature does a heat pump stop working? It depends on the model. Many standard heat pumps keep running to about 0°F to -10°F, but with much less heat output, so backup heat helps on cold days. Cold-climate models like Mitsubishi Hyper-Heat are rated to heat down to about -13°F to -22°F.
How cold can a heat pump work? Leading cold-climate heat pumps deliver full heating capacity at 5°F and keep heating below zero. Standard models start losing capacity in the 20s and 30s°F.
What's the best thermostat setting for a heat pump in winter? Around 68°F, kept steady. Avoid large setbacks that trigger backup heat.
Does a heat pump also cool? Yes. A heat pump runs in reverse in summer and cools your home just like a central air conditioner.
Get a Free Heat Pump Install Estimate
Thinking about a heat pump? Call Air Comfort Technologies at (717) 855-4101. Install estimates are free, financing is available on new systems, and we offer a 10% military discount.