Space heater vs central heat: which is cheaper?
A space heater saves money only if the central heat you no longer buy costs more than the electricity the heater uses. That depends mostly on your heating fuel. In our example (one 200 sq ft room, 8 hours a day, the rest of the home 6°F cooler), the heater saves money in 40 of 51 states for homes heated with oil, 16 with propane, 51 with electric baseboard or furnace, none with natural gas and none with a heat pump.
Pennsylvania, natural gas furnace, 1,800 sq ft home
The space heater costs about $90 more a winter
| Central heat saved | $47 (6% of $788 a year) |
|---|---|
| Space heater | $138 (659 kWh at 20.90¢) |
At night: an electric blanket instead
A 100 W blanket on all night for 150 nights costs $25; the night turn-down saves $47 of central heat. Net: about $22 saved a winter.
Estimates for planning. The room's heat is its share of the home's floor area and hours, plus 25% for heat lost to the cooler rooms around it.
Why the fuel decides
A space heater turns each kWh into 3,412 Btu of heat, no more. A gas furnace, oil boiler or propane furnace turns fuel into heat at 80 to 95% efficiency, and a heat pump moves 2 to 3 units of heat for every unit of electricity. So the question is what a million Btu of heat costs you each way:
- Natural gas furnace: $17 per million Btu of heat
- Heat pump: $23 per million Btu of heat
- Propane furnace: $31 per million Btu of heat
- Electric furnace or baseboard: $53 per million Btu of heat (the same as a space heater)
- Heating oil furnace: $53 per million Btu of heat
U.S. average prices: electricity 18.06¢/kWh (12-month average), natural gas $16.34/Mcf, propane $2.73/gal and heating oil $6.23/gal (week of October 26, 2026), with the default efficiencies of the heating calculator. The trade is a share of the whole home's heat at your central price against one room's heat at the resistance price: the further your central heat is below resistance heat per million Btu, the less a space heater can save.
Space heater vs central heat in every state
| State | Natural gas | Propane | Heating oil | Electric resistance | Heat pump |
|---|---|---|---|---|---|
| Alabama | +$24 | saves $10 | saves $26 | saves $19 | +$21 |
| Alaska | +$290 | +$205 | +$101 | saves $27 | +$189 |
| Arizona | +$9 | +$0 | saves $17 | saves $11 | +$10 |
| Arkansas | +$19 | +$7 | saves $48 | saves $19 | +$32 |
| California | +$59 | +$51 | +$32 | saves $6 | +$42 |
| Colorado | +$60 | +$18 | saves $51 | saves $39 | +$35 |
| Connecticut | +$107 | +$26 | +$20 | saves $52 | +$62 |
| Delaware | +$47 | saves $5 | saves $27 | saves $24 | +$38 |
| District of Columbia | +$56 | +$21 | +$4 | saves $23 | +$37 |
| Florida | +$4 | saves $9 | saves $7 | saves $4 | +$7 |
| Georgia | +$23 | saves $6 | saves $30 | saves $18 | +$29 |
| Hawaii | +$72 | +$108 | +$82 | saves $11 | +$77 |
| Idaho | +$47 | saves $12 | saves $69 | saves $29 | +$26 |
| Illinois | +$84 | +$49 | saves $54 | saves $64 | +$42 |
| Indiana | +$62 | +$8 | saves $68 | saves $51 | +$33 |
| Iowa | +$43 | +$19 | saves $67 | saves $43 | +$25 |
| Kansas | +$35 | +$11 | saves $63 | saves $41 | +$24 |
| Kentucky | +$29 | saves $6 | saves $44 | saves $24 | +$26 |
| Louisiana | +$14 | saves $5 | saves $24 | saves $8 | +$14 |
| Maine | +$109 | +$55 | +$33 | saves $56 | +$66 |
| Maryland | +$70 | +$10 | saves $13 | saves $30 | +$48 |
| Massachusetts | +$98 | +$58 | +$32 | saves $57 | +$68 |
| Michigan | +$108 | +$47 | saves $43 | saves $78 | +$51 |
| Minnesota | +$63 | +$24 | saves $64 | saves $55 | +$32 |
| Mississippi | +$25 | saves $7 | saves $36 | saves $21 | +$22 |
| Missouri | +$26 | +$2 | saves $77 | saves $42 | +$24 |
| Montana | +$60 | +$12 | saves $74 | saves $38 | +$34 |
| Nebraska | +$29 | +$8 | saves $64 | saves $35 | +$20 |
| Nevada | +$21 | saves $4 | saves $32 | saves $15 | +$14 |
| New Hampshire | +$85 | +$31 | +$16 | saves $46 | +$54 |
| New Jersey | +$118 | +$19 | saves $3 | saves $49 | +$71 |
| New Mexico | +$40 | saves $7 | saves $43 | saves $26 | +$23 |
| New York | +$107 | +$49 | +$23 | saves $45 | +$66 |
| North Carolina | +$25 | saves $14 | saves $28 | saves $17 | +$27 |
| North Dakota | +$47 | +$13 | saves $103 | saves $46 | +$27 |
| Ohio | +$66 | +$14 | saves $60 | saves $58 | +$38 |
| Oklahoma | +$28 | +$10 | saves $46 | saves $18 | +$31 |
| Oregon | +$55 | +$24 | saves $23 | saves $7 | +$50 |
| Pennsylvania | +$90 | +$30 | saves $12 | saves $41 | +$59 |
| Rhode Island | +$142 | +$55 | +$32 | saves $73 | +$86 |
| South Carolina | +$26 | saves $9 | saves $21 | saves $15 | +$24 |
| South Dakota | +$45 | +$13 | saves $70 | saves $41 | +$24 |
| Tennessee | +$35 | saves $19 | saves $53 | saves $24 | +$26 |
| Texas | +$17 | +$1 | saves $19 | saves $12 | +$20 |
| Utah | +$38 | saves $3 | saves $61 | saves $27 | +$24 |
| Vermont | +$80 | +$17 | +$1 | saves $44 | +$51 |
| Virginia | +$45 | saves $12 | saves $29 | saves $24 | +$38 |
| Washington | +$48 | +$17 | saves $33 | saves $7 | +$49 |
| West Virginia | +$64 | saves $20 | saves $44 | saves $30 | +$49 |
| Wisconsin | +$74 | +$40 | saves $48 | saves $57 | +$37 |
| Wyoming | +$51 | +$6 | saves $76 | saves $40 | +$35 |
How we estimate it
- Central heat saved: turning the thermostat back 7 to 10°F for 8 hours a day can save up to 10% a year on heating (U.S. Department of Energy), about 1% per °F per 8 hours. 6°F for 8 hours is 6% of the year's heating cost. Change it in the calculator if you know better.
- The room's heat: its share of the home's floor area and of the day, plus 25% because a warm room loses heat through inside walls and doors to the cooler rooms around it (our assumption).
- The typical home's heat comes from EIA's Residential Energy Consumption Survey (RECS 2020), the same basis as the heating cost calculator. Your own heating bills are better: enter last winter's total.
- Heat pumps: a big turn-down can make a heat pump use its electric backup strips when it warms the house back up, which can erase the saving. A smaller setback, or a thermostat with heat pump recovery, avoids that.
- Safety: plug a space heater straight into a wall outlet, not an extension cord or power strip, and keep it well away from anything that can burn.
Related: what a space heater costs per hour · heat pump vs gas, propane and oil · why did my electric bill go up?