Fix it
Space Heater Not Working? 4 Fixes (2026)
Space heater won't turn on, keeps shutting off, or no heat? Four common causes and fixes before you replace it.
Most space heater failures are power issues, safety shut-offs doing their job, or dirty components. Run through these four before buying a new one.
Heater will not turn on
Plug it directly into a wall outlet, not a power strip or extension cord, which can prevent proper operation. Check the outlet with another device. Many heaters have a tip-over switch on the base; make sure the unit sits flat and the switch is not stuck.
Runs then shuts off
This is usually the overheat protection working correctly. Clear dust from the intake and exhaust grilles, move the heater away from walls and curtains, and let it cool for 30 minutes before restarting. If it still cuts out in open space, the thermal fuse may have blown.
Fan runs but no heat
Check that the thermostat is set above room temperature and the unit is not stuck in fan-only mode. On oil radiators, a tripped internal thermal cut-off needs a cool-down period. If the element never engages, the heating element or thermostat has likely failed.
Burning smell
A slight odor on first use of the season is normal dust burn-off and should fade within an hour. A persistent acrid smell means unplug it immediately and inspect for melted plastic, scorched cords, or debris inside the grille. Do not continue using a heater that smells of burning plastic.
Questions, answered
Why does my heater trip the breaker?
1500 watts uses most of a 15-amp circuit. Move the heater to an outlet on a different circuit and unplug other heavy devices on the same one.
Can I use an extension cord?
Manufacturers advise against it. If you must, use a single heavy-duty cord rated for 1500 watts or more, fully uncoiled, and only temporarily.