Space heaters are one of the most common household appliances — and one of the most misunderstood when it comes to energy costs. A standard 1,500-watt space heater costs about $0.20–$0.45 per hour to run depending on your electricity rate, adding up to $50–130 per month at typical winter usage. Whether that's more or less than what you're paying for central heat depends on your fuel type, home size, and how you use both systems.
This guide gives you the exact numbers — cost per hour, per day, and per month — and answers the question most people actually want to know: does running a space heater actually save money?
Space Heater Cost Per Hour: The Formula
The calculation is straightforward: Cost per hour = Wattage ÷ 1,000 × Electricity rate
For a standard 1,500W space heater at common U.S. electricity rates:
- Idaho / Pacific Northwest (~9¢/kWh): $0.14/hr
- Texas / Midwest (~11¢/kWh): $0.17/hr
- U.S. average (~16¢/kWh): $0.24/hr
- California (~25¢/kWh): $0.38/hr
- Hawaii (~40¢/kWh): $0.60/hr
- New England (~22¢/kWh): $0.33/hr
For a precise calculation based on your specific wattage and local rate, use our Space Heater Cost Calculator.
Space Heater Cost Per Day and Per Month
At the U.S. average electricity rate of 16¢/kWh, here's what a 1,500W space heater costs at different usage levels:
- 4 hours/day: $0.96/day → $28.80/month
- 8 hours/day: $1.92/day → $57.60/month
- 12 hours/day: $2.88/day → $86.40/month
- 24 hours/day: $5.76/day → $172.80/month
Most people running a space heater in a home office or bedroom during working or sleeping hours are looking at the 8-hour figure — about $58/month at average rates. In California, that same 8-hour day costs about $90/month.
Cost by Wattage: Not All Space Heaters Are Equal
Space heaters range from 750W to 1,500W, with most full-size models offering both settings. At 16¢/kWh and 8 hours/day:
- 750W (low setting): $0.12/hr → $0.96/day → $28.80/month
- 1,000W (medium): $0.16/hr → $1.28/day → $38.40/month
- 1,500W (high setting): $0.24/hr → $1.92/day → $57.60/month
Using the low or medium setting when it provides adequate warmth cuts running costs by 33–50% with no other change. Most modern ceramic and infrared heaters have thermostats that cycle the heater on and off to maintain temperature, so the effective wattage is often lower than the nameplate rating.
Do Space Heaters Actually Save Money?
This is the real question — and the honest answer is: sometimes, but only under specific conditions.
When Space Heaters DO Save Money
A space heater saves money when you use it to heat one room and simultaneously reduce the central thermostat by at least 5–10°F. The math works because you're reducing the whole-home heating load (which costs more, especially for large homes) and replacing it with targeted heating for the space you're actually occupying.
Example: A gas-heated home spending $200/month in January. Dropping the central thermostat from 70°F to 62°F saves roughly 24% on heating (~$48/month). Adding a space heater in the living room for 8 hours costs about $58/month at average electricity rates — a net loss of $10/month in this case. But if the thermostat setback is larger (to 60°F) or the home is large and gas is expensive, the math can favor the space heater.
Space heaters work best for zone heating in specific situations: a cold home office where you work all day, a bedroom where you sleep with the rest of the house cooler, or a poorly insulated room that requires extra heat regardless.
When Space Heaters Do NOT Save Money
Running a space heater while leaving the central thermostat at the same setting almost always costs more. You're adding the heater's electricity cost on top of the central heating cost with no offset. Similarly, using a space heater to heat multiple rooms or a large open area is almost always more expensive than central heat — a 1,500W heater simply isn't designed to replace a whole-home system.
Households with gas heat face a particular challenge: natural gas is significantly cheaper per BTU than electricity in most U.S. markets. At current prices, 1 kWh of electricity costs about $0.16 at the meter, while 1 kWh-equivalent of natural gas costs about $0.04–$0.06. This 3–4x difference means an electric space heater almost never saves money vs. a gas furnace unless used for very targeted zone heating with substantial thermostat setback.
Space Heater vs. Central Heat: The Numbers
For a 1,500 sq ft home with natural gas heat in the Midwest:
- Gas furnace heating the whole home to 70°F: ~$150–200/month in January
- Gas furnace at 62°F + 1,500W space heater 8 hrs/day in one room: ~$115–155/month total
- Savings: ~$35–50/month — possible, but requires disciplined thermostat management
For an all-electric home with electric resistance baseboard heat:
- Electric baseboards heating the whole home: ~$250–350/month in January
- Baseboards at 60°F + 1,500W space heater in one room 8 hrs/day: ~$200–280/month
- Savings: marginal at best — same fuel cost per BTU
For households considering a heat pump, see our Heat Pump vs. Furnace comparison — heat pumps are 2–4x more efficient than resistance heating at producing the same warmth.
Safety Considerations
Space heaters cause about 1,700 home fires per year in the U.S., according to NFPA data — primarily from units placed too close to flammable materials or left unattended. Key safety rules: keep 3 feet clear of anything flammable, never leave a space heater running unattended or while sleeping, plug directly into a wall outlet (not an extension cord), and replace any heater with a frayed cord or damaged element immediately. Modern space heaters include tip-over protection and overheat shutoff, which significantly reduce risk.
Choosing the Right Space Heater
For most residential use, a 1,500W ceramic or infrared heater with a built-in thermostat is the right choice. Ceramic heaters heat a room quickly; infrared heaters heat people and objects directly (useful if you're stationary at a desk). Oil-filled radiators are slower to heat but maintain temperature more efficiently over long periods with less cycling.
Avoid overpowering the space: a 1,500W heater is designed for roughly 150 sq ft. Heating a larger space with a small heater means it runs at full power continuously, eliminating the efficiency benefits of the thermostat.