Cold snaps push a home’s electrical system to its limits. Space heaters come out, kitchens run harder, and HVAC equipment draws more power. If your breaker starts tripping whenever the temperature drops, it is doing its job to prevent overheated wiring. The key is deciding whether you have a simple overload or a problem that needs an electrician.
This guide explains how winter loads change, why space heaters and emergency heat are common culprits, what temperatures affect heat pump performance, and what you can do today to stay safe and comfortable.
What cold weather does to your circuits and HVAC
When outdoor temperatures fall, heat pumps become less efficient. Below roughly 40°F most non–cold climate units deliver less heat per kilowatt. Many thermostats are set with a balance point around 35°F, which is the temperature where the heat pump alone can no longer keep up with the home’s heat loss. At or below that balance point the system brings on auxiliary or emergency heat.
If you have an electric air handler, that auxiliary heat is a set of large electric heat strips. They draw a lot of current for as long as the call for heat continues, which raises your overall electrical load during cold weather. Homes with gas furnaces do not use heat strips. They still use power for the blower and controls, but overall draw is much lower.
How cold is “too cold” for a typical heat pump
Around 40°F and below: Efficiency falls. You may notice longer run times.
Around 35°F: Many systems start auxiliary heat to help maintain setpoint. The exact temperature is adjustable, so yours may be a few degrees higher or lower.
Around 25–30°F: Standard heat pumps still run, but capacity is limited. Some installers program a compressor lockout in this range so the system switches to heat strips only.
Below 15–20°F: Many non–cold climate units provide very little usable heat. The system may appear to stop “working” because emergency heat carries nearly all the load.
Cold climate models can operate well below these numbers. If you replaced your system recently, check your manual or ask your technician which kind you have and what your lockout settings are.
Space heaters and the hidden math of overloads
Most portable space heaters are rated around 1500 watts. On a 120 volt circuit that is about 12.5 amps. Many bedroom and living room circuits use 15 amp breakers. One heater can consume almost the entire circuit on its own. Add a vacuum, hair dryer, game console, or a few chargers and lights, and you can cross the limit quickly. The breaker trips to protect the wiring.
Trips that occur after several minutes of heater use usually indicate overload, not a bad breaker. Signs of a failing breaker include tripping at light loads, refusal to reset, a hot handle, or discoloration. Buzzing at the panel or immediate re-trips with nothing plugged in are reasons to call a licensed electrician.
Safe steps you can try before calling a pro
Start with simple changes that reduce load and improve safety. Never install a larger breaker to stop trips. The breaker rating matches the wire size.
Quick homeowner checklist
Move the space heater to a different room so it is on another circuit, and keep it as the only device on that receptacle.
Do not use power strips or extension cords with a heater. Plug it directly into a wall outlet and keep clear space around it.
Stagger high draw appliances. Avoid running a microwave, toaster oven, or hair dryer while a heater is on the same general branch.
Test and reset any GFCI or AFCI devices. Persistent trips indicate a fault that needs diagnosis, not a bigger breaker.
Stop using any outlet or plug that feels warm and schedule an inspection.
If your home uses a heat pump with electric backup, expect longer run times and higher electrical demand during cold spells. That is normal, but it means balancing other loads becomes more important.
When a dedicated circuit or panel work makes sense
If you rely on a space heater to make a room usable, a dedicated 20 amp circuit with the correct wire size is usually the right fix. Dedicated circuits are also smart for treadmills, window AC units, chest freezers, and workshop heaters. They keep heavy loads off general lighting and receptacle circuits and reduce nuisance trips.
Panel condition matters too. Crowded panels, doubled-up wires, corroded bus bars, or mismatched breakers can all lead to heat and intermittent trips. An evaluation can confirm whether you need simple maintenance, new breaker installation, or an electrical panel upgrade to support modern loads. If you have a heat pump, your electrician can also review any compressor lockout or heat-strip settings to ensure the system is wired and configured safely for your climate.
Final thoughts
Winter breaker trips are common. A 1500 watt space heater can consume almost an entire 15 amp circuit, and electric emergency heat can raise overall household demand during cold snaps. Balance your loads, keep heaters on their own receptacle, and never upsize a breaker. If tripping persists at light use, or if you see signs of heat or damage, bring in a licensed pro.
If you want help identifying overloaded circuits or you are ready for a dedicated heater circuit, A Team Home Services can test your panel, check breaker health, confirm heat pump settings, and add the capacity you need safely and cleanly.