Homeowners' pick for heating and cooling across north Florida and the Suwannee Valley
Heat Pump Running Nonstop in Cold Weather
Your heat pump has been running for hours and the house still feels cool. That is the question we get every time the temperature drops into the thirties across Florida, Georgia and South Carolina. Long run times in cold weather are often normal. Long run times plus a house that never reaches the setpoint are not. Here is how to tell the difference before you call us.
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By the Suwannee Valley AC & Heating service team · reviewed by our working technicians
What Constant Running Actually Means in Cold Weather
A heat pump does not blast hot air the way a furnace does. It moves heat from outdoor air into your home, and the colder it gets outside, the less heat there is to move. So the unit runs longer on purpose. On a 35 degree morning, a correctly sized system may run almost continuously and still hold your thermostat setting. That is the design working. The warning sign is different: the unit runs nonstop and the indoor temperature drifts down, or your electric bill jumps because backup heat strips are carrying the whole load. Watch the thermostat reading, not the clock.
Cause One: Airflow and Thermostat Settings
Start with the cheapest things, because they cause more nonstop running than anything else. A filter packed with dust and pet hair chokes airflow, so the system moves heat slowly and never catches up. Closed or blocked supply vents do the same in reverse. On the thermostat, an "emergency heat" or "aux heat" setting left on will run strips constantly, and a fan set to ON instead of AUTO makes the system sound like it never stops even when it is cycling normally. Weak thermostat batteries cause odd readings too. These are all things you can look at yourself in ten minutes.
Cause Two: The Outdoor Unit and Defrost
In cold damp weather, frost forms on the outdoor coil, and the system periodically reverses to melt it off. That is normal defrost. What is not normal is a solid block of ice on the coil, or ice that never clears. When the defrost control, sensor or reversing valve fails, the unit keeps running against a frozen coil and delivers almost no heat. Out on rural routes we also see coils packed with pine straw, sand and lawn clippings, and units sitting where sprinkler spray freezes on them. Clearing leaves and debris a couple of feet back from the cabinet is safe homeowner work. Chipping at ice is not.
Cause Three: Refrigerant Charge, Sizing and Duct Loss
If airflow is clean and the coil is clear, the problem is usually in the sealed side of the system or in the ductwork. A low refrigerant charge means a leak, and a leak means the system carries less heat per cycle and runs forever trying. We test and repair that, never a homeowner. Ducts running through a hot attic or a vented crawlspace leak conditioned air into places nobody lives, and in sandy-soil homes with older flex duct we find crushed runs and separated boots often. Undersized equipment, or a system installed for a house that has since been added onto, shows the same symptom.
What a Technician Does That You Cannot
We start with real numbers instead of guesses. We measure temperature split across the indoor coil, static pressure in the duct system, amp draw on the compressor and the heat strips, and refrigerant pressures against outdoor conditions. We check whether the reversing valve is actually shifting, whether the defrost board is calling on schedule, and whether backup heat is locking in when it should not. Then we tell you which repair fixes the run time and which one just moves the problem. For heating repair, heater repair or furnace repair on gas equipment, we also verify safe combustion. If you ever smell gas, leave the house, call 911 or your gas utility, then call us.
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Heat Pump Running Nonstop in Cold Weather — common questions
Is it bad for a heat pump to run all day in winter?
Not by itself. Continuous running in cold weather is normal design behavior as long as the house holds your thermostat setting. Call us if the indoor temperature keeps falling or the outdoor coil stays iced over.
Should I switch to emergency heat if it feels cool?
Only briefly, and only if the heat pump has clearly stopped heating. Emergency heat runs electric strips and costs far more to operate. Switch back and call us for heating repair rather than leaving it on for weeks.
Why does my outdoor unit steam and get loud sometimes?
That is a defrost cycle melting frost off the coil. It lasts several minutes, sounds different, and may briefly blow cool air indoors. If it happens constantly or ice never clears, the defrost controls need testing.
How it works
- Step 1
Tell us the symptoms
You describe what changed. No cold air, a breaker that keeps tripping, water near the air handler, a smell, a noise. That gives us a head start on parts before we ever leave the shop.
- Step 2
We diagnose on site
A technician checks the thermostat, the electrical side, airflow through the filter and coil, refrigerant behavior and the outdoor unit. We look at the whole system, because a frozen coil usually points somewhere else.
- Step 3
You decide the repair
We explain what failed, what it takes to fix it, and how long the rest of the system is likely to hold up. You pick the repair. We do not start work you did not approve.
- A real person answers
- Open 7 days
- Written quote before work starts
Why homeowners call us
- Rural routes are normal for usWe drive long stretches between calls and we plan for it. Trucks carry the common heat pump and air conditioner repair parts so a diagnosis does not turn into a second trip on a hot afternoon.
- Heat pumps and sandy soilMost homes we visit run a heat pump, and sand, lawn clippings and pollen pack the outdoor coil fast. We clear it, check the defrost side in winter, and show you what we found before we close it up.
- Well water housesHomes on well water bring their own quirks, from pump-driven electrical noise to hard water on drain lines and condensate pans. We know where those systems clog and where the slow leaks hide.
- Heating repair tooCold snaps in this region are short and hard. We do heating repair and heater repair on heat pumps, strip heat and furnaces, so one crew handles your system in July and again in January.
- All major brands, gas & electricOne independent crew for Carrier, Trane, Lennox, Goodman, Rheem and more.
- Straight answersIf a system is not worth repairing, we say so, often right on the phone.
About this guide
When the easy checks change nothing, it's time for a tech
Report what you saw during the checks and we handle the rest. A minute to book.
- A real person answers
- Open 7 days
- Written quotes
- All major brands
- Gas & electric
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