Heat Pump Not Heating? Winter Heat Pump Problems in Hampton and Newport News

Most winter heat pump calls we take in Hampton and Newport News follow a few patterns: the system runs all night, the thermostat says AUX, the air feels cool, or the outdoor unit is frosted over. Some of that is normal cold-weather behavior, and some of it needs a technician. Here is how to tell which is which.

Is it normal for a heat pump to run constantly in cold weather?

On the coldest nights, a heat pump that runs nonstop is usually doing its job. A heat pump pulls heat out of the outdoor air, and the colder that air gets, the less heat each hour of running delivers. January nights on the Peninsula average right around freezing, and a cold snap into the 20s pushes most systems to run continuously just to hold the setpoint. Last February, on a 26-degree morning, a homeowner called us about a rental whose system would not shut off. With the thermostat at 76, our office explained, it was not going to cut off until the weather warmed. Long run times become a problem when the house keeps losing temperature, when the system runs nonstop on a 45-degree day, or when the electric bill climbs far past last winter’s.

What is the difference between auxiliary heat and emergency heat?

Auxiliary heat turns on by itself, while emergency heat is a setting you choose. Both usually run the same electric heat strips inside the air handler, and both cost more to run than the heat pump. AUX on the thermostat means the strips are helping the heat pump, which is normal on very cold nights, during a defrost cycle, or after you raise the thermostat more than two or three degrees at once. Emergency heat shuts the outdoor unit off and heats the house with the strips alone. Use it only when the outdoor unit has failed or is encased in ice, and call for service the same day.

Thermostat shows	Normal when	Call us when
HEAT (heat pump only)	Mild and cool weather	It cannot hold the setpoint above about 40°F
AUX (heat pump plus heat strips)	Cold nights, defrost, after a big setpoint increase	AUX runs for long stretches in mild weather
EM HEAT (heat strips only)	The outdoor unit has failed and you switched it on	Always, the same day

Why is my heat pump blowing cold air?

A heat pump often blows air that feels cool even when it is heating normally. Heat pump air usually leaves the registers at about 90 to 110 degrees, well below what a gas furnace puts out, and air below body temperature can feel cool on your hand. A thermometer at the register tells you more than your hand does. Two short-lived causes are also normal. During a defrost cycle the system briefly reverses, so the air can turn cooler for a few minutes unless the heat strips cover it. With the fan set to ON instead of AUTO, the blower keeps moving room-temperature air between heating cycles.

Cold air that lasts more than a few minutes, especially with the outdoor unit silent or iced over, usually means a failed outdoor fan, a stuck reversing valve, a refrigerant leak or a tripped outdoor breaker. That needs a service call.

Why is my heat pump covered in frost or ice?

A light coat of frost on the outdoor coil is normal in damp weather in the 30s, and humid Peninsula winters produce plenty of it. The heat pump clears it with a defrost cycle: the outdoor fan stops, the system reverses for a few minutes, and you may see steam rising off the unit as the frost melts. Then heating resumes.

The warning sign is ice that stays. A solid sheet over the coil that is still there after an hour or two, ice on top of the unit, or ice building from the base up all mean the defrost cycle is not keeping up. Common causes are a failed defrost control or sensor, low refrigerant, a stopped outdoor fan, or a gutter dripping onto the unit. Never chip ice off with a tool, because the fins and tubing bend and puncture easily. Switch to emergency heat and call us.

Why does my heat pump turn on and off so often?

A heat pump that starts, runs a few minutes, shuts off and starts again is short cycling, and unlike a long run time on a cold night, it is not normal. Short cycling wears on the compressor and leaves rooms uneven. Check the simple causes first: a clogged air filter, closed or blocked supply vents, or a thermostat sitting in sun or near a supply register. If those check out, the cause is usually a refrigerant problem, a failing sensor, or a system too large for the house. An oversized heat pump warms the air near the thermostat quickly and shuts off before the rest of the house catches up. No repair fixes that one. It gets solved with a load calculation at heat pump replacement time.

At what temperature does a heat pump stop working?

Most heat pumps keep heating well below freezing, and there is no single cutoff temperature. Every system has a balance point, the outdoor temperature below which the heat pump alone cannot keep up with the home’s heat loss, and below it the heat strips fill the gap. For many single-stage systems that point sits near freezing, while variable-speed and cold-climate models carry the house much lower on their own. On the Peninsula, where winter nights average around freezing and deep cold snaps are short, an ordinary heat pump with properly sized backup heat handles the climate well. If yours needs AUX at 45 degrees, the problem is the system, not the weather.

Which winter heat pump signs are normal, and which need a technician?

Anything in the right-hand column is worth a service call.

Usually normal	Needs a technician
Runs nonstop on nights in the 20s	Cannot hold temperature above about 40°F
AUX shows on cold nights or during defrost	AUX runs for long stretches in mild weather
Steam rising from the outdoor unit for a few minutes	Ice that does not clear, or ice on top of the unit
Air from the registers feels mild, not hot	Cold air for more than a few minutes
A whoosh when defrost starts or ends	Grinding, banging or hissing from the unit
A higher bill in January than in October	A bill far above the same month last winter

What winter habits make heat pump problems worse?

The most common one is a deep night setback. Dropping the thermostat 8 or 10 degrees overnight saves less on a heat pump than on a furnace, because the morning recovery often runs on the heat strips. Keep setbacks to a couple of degrees, or use a thermostat that warms the house gradually. Other habits to avoid:

• Leaving emergency heat on after the outdoor unit is fixed
• Letting the air filter clog, which can bring on AUX even in mild weather
• Crowding the outdoor unit with shrubs, leaves, a cover, or an overflowing gutter
• Skipping the fall tune-up, which tests the defrost cycle, refrigerant charge and heat strips before the first cold snap

A tune-up is where small failures get caught. Last December, Lewis, one of our technicians, found a failing capacitor on a customer’s heat pump during a routine maintenance visit and replaced it the same day. Our Comfort PLUS Club maintenance plan puts those visits on a schedule.

Frequently Asked Questions

Why did my electric bill jump when it got cold?

Most of a winter jump on a heat pump bill comes from heat strip run time. Heat strips turn electricity into heat one for one, while a heat pump moves heat from outdoors and delivers more heat than the electricity it draws, so every hour on AUX costs more than an hour on the heat pump alone. A bill far above the same month last winter, in similar weather, usually means the strips are carrying a load the heat pump should be handling.

Does Kearney & Sons repair all heat pump brands?

Kearney & Sons services all makes and models, including Goodman, Trane, Carrier, Ruud and Daikin heat pumps. We install Bryant, York, Rheem, Bosch and Mitsubishi Electric equipment, and our technicians are NATE certified.

Heat pump still not keeping up?

If your heat pump cannot hold temperature, stays on AUX in mild weather, or is iced over, Kearney & Sons can help. We repair heat pumps across Hampton, Newport News, Williamsburg and the rest of the Peninsula, with 24/7 availability for no-heat emergencies. Schedule heat pump repair or request service online.