When you're cold in one room, is it cheaper to turn up the central heat or plug in a space heater? The answer depends on your situation: heating one room with a space heater can save money compared to heating the whole house, but electric space heaters are inefficient—and central systems vary widely by fuel type.
How Space Heaters Work
Electric resistance space heaters convert nearly 100% of electricity into heat. That sounds efficient, but electricity is expensive per unit of energy compared to natural gas. A typical 1,500-watt space heater running 8 hours uses 12 kWh per day—about $1.44 at $0.12/kWh, or $43 per month for one room.
Central Heating: Electric vs. Gas vs. Heat Pump
Electric furnaces also use resistance heating—they're similarly "efficient" in converting electricity to heat but costly to run. Gas furnaces use natural gas, which is often 2–3 times cheaper per unit of heat. Heat pumps move heat from outside into your home and can deliver 2–4 units of heat per unit of electricity—making them far more efficient than resistance heating.
When a Space Heater Saves Money
Space heaters can save money when you have central electric heat and only need to warm one or two rooms. Instead of heating the entire house to 72°F, keep the thermostat at 65°F and use a space heater in the room you're using. You're trading whole-house heating for targeted heating—and that can cut costs by 20–40% if you're disciplined about it.
When Central Heating Is Better
If you have a gas furnace or heat pump, central heating is usually cheaper than multiple space heaters. Gas is inexpensive, and heat pumps are highly efficient. Running several space heaters can exceed the cost of running your central system. Also, space heaters pose fire and tip-over risks if not used carefully.
Efficiency and Safety Considerations
- Oil-filled radiators: Slower to heat but retain heat; good for sustained use.
- Ceramic heaters: Heat quickly; many have tip-over and overheat protection.
- Infrared heaters: Heat objects directly; feel warm quickly but don't heat the air.
- Never leave unattended: Space heaters cause thousands of fires annually.
- Keep 3 feet from flammables: Follow manufacturer safety guidelines.
"The best strategy: lower your central thermostat and use a space heater only in the room you're in. Turn it off when you leave. That targeted approach maximizes savings."
Estimate Your Heating Costs
Use ElectriBill's calculator to compare. Enter 1,500 watts for a space heater (8 hrs/day) vs. your central system's wattage. If you have gas heat, compare the space heater's electric cost to your gas bill to see which makes sense for supplemental heating.