By Commercial Service Company · October 19, 2026
Central Arkansas doesn't get brutally cold for long, but when a hard freeze hits, commercial heat pumps work harder than they do the rest of the year. If yours seems to run nonstop, or the building never quite feels warm, you're not imagining it. Some of that is normal heat pump behavior in cold weather. Some of it is a sign of real trouble. Knowing the difference can save you a service call you don't need, or help you catch a problem before it leaves you without heat on the coldest day of the year.
Why Heat Pumps Work Harder in Cold Weather
A heat pump doesn't generate heat the way a furnace does. It pulls heat out of the outdoor air and moves it inside. The colder it gets outside, the less heat there is to pull, and the harder the system has to work to keep up. On a 35-degree day, a heat pump runs efficiently. On a 20-degree day, that same unit may run almost continuously just to hold the temperature you've set. That's normal operation, not a malfunction.
Longer run times in cold weather are expected. The warning signs to watch for are different: the space getting colder instead of holding steady, the outdoor unit caked in ice that doesn't clear, or the system running constantly without ever satisfying the thermostat even on a mild day.
Defrost Cycles Are Supposed to Happen
In cold, damp weather, frost builds up on the outdoor coil. To deal with this, the system periodically reverses itself, pulls heat from indoors to melt the frost off the outdoor coil, and then switches back to heating. During a defrost cycle, you may notice:
- The outdoor fan stopping for several minutes
- Steam or vapor rising off the outdoor unit as the frost melts
- A brief period where the indoor air feels cooler
- The system cycling into defrost every hour or so during freezing, humid conditions
This is the system doing exactly what it's designed to do. It becomes a problem only when the outdoor coil stays heavily iced over even after a defrost cycle, when defrost cycles run back-to-back with little normal heating in between, or when you see thick ice building on the coil that isn't clearing at all. Those point to an airflow, control, or refrigerant issue that needs a technician's eye, not a DIY fix.
Auxiliary Heat: The System's Backup Plan
Most commercial heat pumps have a backup heat source built in, usually electric resistance heat strips, to help out when the outdoor temperature drops too low for the heat pump alone to keep up, or during defrost cycles when the system is briefly working in reverse. This is often called auxiliary heat or emergency heat.
Auxiliary heat is supposed to kick in occasionally during cold snaps. It's not supposed to run all day, every day. If auxiliary heat is engaging constantly, or if that's the only way the building stays warm, the heat pump itself isn't carrying its share of the load. That usually means something is limiting its capacity, and it's worth having it checked before it turns into a bigger failure or a much higher utility bill.
When Nonstop Running Is a Real Problem
A heat pump running long cycles on a cold day is normal. A heat pump that never stops, never catches up, and leaves the space uncomfortable is telling you something is wrong. Signs worth paying attention to include:
- The thermostat never reaches its setpoint, even after hours of running
- Warm air from the vents feels noticeably cooler than it used to
- The outdoor unit is covered in ice that doesn't clear during normal defrost cycles
- Auxiliary or emergency heat is on almost constantly
- Unusual noises from the outdoor unit, or ice forming somewhere other than the coil
- A sudden jump in utility costs with no change in weather or usage
Any of these can point to low refrigerant charge, a failing defrost control, a blocked outdoor coil, a worn compressor, or an electrical component on its way out. These are not things to troubleshoot yourself. Refrigerant, compressor, and electrical issues need to be handled by a licensed technician who can safely diagnose and repair the system without making things worse or creating a safety hazard.
What You Can Check Before You Call
Before you pick up the phone, there are a few simple, safe things worth a look:
- Make sure the outdoor unit has clear space around it, free of leaves, snow piles, or debris
- Check that indoor vents and returns aren't blocked by furniture, boxes, or stock
- Replace or check air filters if they're overdue
- Confirm the thermostat is set to heat mode and the setpoint is reasonable
If those basics check out and the system still isn't keeping up, it's time to get a professional opinion rather than let it keep running itself into the ground during the coldest stretch of the year.
Call Commercial Service Company
Commercial Service Company has served businesses across Conway, Little Rock, Benton, Bryant, Maumelle, Jacksonville, Searcy, Russellville, and the rest of central Arkansas since 1976. If your commercial heat pump is running nonstop, leaning hard on auxiliary heat, or just not keeping your building warm, give us a call at 501-548-2374 and we'll get a technician out to take a look.