HVAC and Electrical Experts
Written by Peter
Master Electrician at PRO Electric plus HVAC, serving Fairfax, Loudoun, Arlington, and Prince William Counties. Virginia License #2705181607.
Yes, Heat Pumps Work in Our Winters. Here Is How.
Heat pump installation, replacement, and repair across Fairfax, Loudoun, Arlington, and Prince William Counties.
Hi, I am Peter, the Master Electrician at PRO Electric plus HVAC. The most common worry I hear about heat pumps is whether they actually work when it gets cold. It is a fair question, and the old reputation came from older equipment. Let me explain how a modern heat pump performs through a Northern Virginia winter.
The honest answer is that today’s heat pumps handle our winters well, and they have a built in plan for the few truly cold days we get.
What happens as it gets colder
A heat pump pulls heat from the outdoor air, and there is heat in that air even when it feels cold to us. As the temperature drops, there is less of it to pull, so the heat pump works a little harder. Through most of our winter, this is no problem at all. A modern unit keeps a home comfortable across the great majority of the heating season.
Backup heat for the coldest days
On the coldest days, a heat pump uses backup heat to help out, usually electric heat strips or, in a dual setup, a furnace. The system switches over automatically when it needs to, so you stay warm without doing anything. This is normal and by design. It is not a sign of a problem.
What to know so it runs its best
- Let it run. A heat pump heats steadily rather than in short hot blasts, so the air from the vents can feel cooler than a furnace even when it is doing its job. That is normal.
- Understand the defrost cycle. In cold, damp weather the outdoor unit will frost up and run a short defrost cycle. You may see steam and hear it change sound. This is the system working correctly.
- Use the thermostat wisely. Big temperature setbacks can force the backup heat to kick on. A thermostat set up for a heat pump avoids that and keeps bills down.
- Keep up with maintenance. A dirty filter or a blocked outdoor unit makes cold weather performance worse. A seasonal check keeps it strong.
If the heat pump cannot keep up
If your heat pump runs constantly and still cannot hold temperature on a normal winter day, something is off. It could be low refrigerant, a failing component, an undersized unit, or backup heat that is not engaging. That is worth a service call rather than just turning up the thermostat.
The bottom line for our area
For Northern Virginia, a heat pump is a strong heating choice. Our winters sit right in the range where heat pumps shine, and backup heat covers the rest. If you are weighing your options, our comparison of a heat pump versus a furnace lays out the full picture, and the heat pump guide covers how the system works year round. For homes without ductwork, a ductless option is worth a look as well.
Frequently asked questions
Do heat pumps work in cold weather?
Yes. A heat pump pulls heat from outdoor air, and there is usable heat in that air even when it is cold. Modern heat pumps keep homes comfortable through most of a Northern Virginia winter, and they use backup heat automatically on the coldest days.
At what temperature does a heat pump stop working?
A modern heat pump keeps heating well below freezing, and it does not simply stop. As it gets very cold, it leans on backup heat, electric heat strips or a furnace in a dual system, to keep the home warm. For our climate, the heat pump handles the great majority of the season on its own.
Why does my heat pump blow cool air sometimes?
A heat pump heats steadily rather than in hot blasts, so the air can feel cooler than a furnace even when working correctly. You may also feel it during a defrost cycle, when the unit briefly clears frost from the outdoor coil. Both are normal.
What is backup or auxiliary heat on a heat pump?
Backup heat, sometimes called auxiliary or emergency heat, is a secondary heat source, usually electric heat strips or a furnace, that helps the heat pump on the coldest days. The system switches to it automatically when needed, then returns to normal heat pump operation as it warms up.
Why is my heat pump running constantly in winter?
Some longer run times are normal in cold weather because a heat pump heats steadily. But if it runs nonstop and still cannot hold temperature on a normal winter day, something is wrong, such as low refrigerant, a failing part, or backup heat that is not engaging, and it should be checked.
Thinking about a heat pump for our winters?
Heat pump installation and service across Northern Virginia.