It depends on how much space you heat. Running one space heater to warm a single occupied room while lowering the central thermostat is usually cheaper. But heating several rooms with multiple space heaters typically costs more than central heat, because electric resistance heating is expensive per unit of heat compared with a gas furnace.
When is a space heater cheaper?
A space heater saves money when you heat just one occupied room and turn the central thermostat well down. This is zone heating. It avoids paying to warm empty rooms, so the small electric heater's cost is more than offset by the fuel the furnace no longer burns.
The catch is that everyone in the home has to accept the rest of the house staying cool. Zone heating works best in the evening, in a single living room or home office. One warm room covers most of the day's comfort needs as supplemental heat.
When does central heat win?
Once you need warmth in several rooms at once, central heat is usually cheaper and more even. Running three or four electric space heaters to cover a whole house draws far more expensive energy than a single furnace distributing heat through ducts.
Central systems also hold a steadier indoor climate across the home. They avoid the cold hallways and uneven temperatures you get when only a few portable heaters are running.
How do the fuel costs compare?
Electric resistance heat is essentially 100 percent efficient at the point of use. But electricity is expensive per unit of heat. Natural gas typically delivers heat at a lower cost per BTU. That is why whole-home gas heating usually beats whole-home electric heater use.
Your local electricity and gas rates decide the exact break-even point. Check both on your utility bills before assuming either is cheaper for your situation.
Which type of space heater is cheapest to run?
Every plug-in electric heater draws roughly the same power for the same wattage. A 1500 watts ceramic model, an oil-filled radiator, and an infrared unit cost about the same to run per hour. What differs is how efficiently that heat reaches you, which changes how long you need it on.
Brands like DREO, Lasko, and Vornado sell across most of these formats. The running cost gap between models usually comes down to thermostat precision, not the underlying watts.
Ceramic and fan-forced vs radiant heat
A ceramic or tower heater is fan-forced, blowing warm air across the room for quick, even coverage. An oil-filled radiator delivers slow, steady radiant heat instead, warming objects and people directly. Radiant heat can feel efficient in a small, still room, since it keeps working after the element cycles off.
Infrared, oscillation, and thermostat cycling
Infrared heaters warm people and surfaces almost instantly rather than heating the air itself. That suits a garage or workspace you enter briefly. A thermostat with oscillation spreads fan-forced heat across a wider area, so the unit cycles less often and holds a steadier running cost.
Is an electric heater energy efficient supplemental heat?
Every electric heater turns close to 100% of its electricity into heat. So wattage alone does not separate an efficient model from a wasteful one. Energy efficient supplemental heat comes from matching the unit to the room, not from any special technology inside it.
A well-matched portable heater warms one occupied space for a fraction of the cost of raising the whole house's temperature. That is the entire case for using supplemental heat instead of leaning on central heat alone.
1500 watts, BTU, and portable heater running cost
Most plug-in models top out near 1500 watts, the practical limit for a standard outlet. That translates to a fixed BTU output regardless of brand. A portable heater's running cost scales directly with watts and hours used, not with its shape or features.
Oil-filled radiators and tower heater options
An oil-filled radiator holds heat in its fluid and keeps radiating warmth after the element shuts off. That can smooth out running cost over an evening. A tower heater instead uses fan-forced air for faster, more even coverage across a larger room.
Are tip-over and overheat safety features worth paying for?
Yes. Tip-over and overheat cutoffs are standard on reputable portable heaters and cost little to nothing extra. They do not change the running cost of heating. But they are essential on any electric heater left on near furniture, pets, or kids.
The EPA and most fire-safety guidance treat these cutoffs as a baseline requirement, not a premium feature. That holds whenever a space heater is used as supplemental heat instead of a central system.
Our space heaters hub covers where portable units fit best, and the efficient heating and cooling guide digs into zone heating. See How We Rank for how we source our guidance.