Homes in Idaho paid 13.37¢ per kWh on average in August 2026. Nationally the figure was 18.16¢, 26% higher. Prices are up 10.7% from 12.08¢ a year earlier.
At that price a 1,500-watt space heater on high costs about $0.20 an hour. Eight hours a day for 30 days comes to $48.13. Four hours a day on high instead is about $24.07 a month, and 8 hours on the 900 W low setting about $28.88. That is $17.24 a month less than at the U.S. average price.
Work out your cost in Idaho
Change any number. The price per kWh is printed on your electric bill.
Starts at Idaho's average residential price, 13.37¢/kWh. Source: U.S. EIA, Electric Power Monthly, Table 5.6.A (residential sector), August 2026 (released October 23, 2026). Month is 30 days; year is 12 such months.
Monthly cost by setting and hours
| Use | Idaho, August 202613.37¢/kWh | Idaho, August 202512.08¢/kWh | U.S. average18.16¢/kWh |
|---|---|---|---|
| Low, 900 W, 4 h a day108 kWh a month | $14.44 | $13.05 | $19.61 |
| High, 1,500 W, 4 h a day180 kWh a month | $24.07 | $21.74 | $32.69 |
| Low, 900 W, 8 h a day216 kWh a month | $28.88 | $26.09 | $39.23 |
| High, 1,500 W, 8 h a day360 kWh a month | $48.13 | $43.49 | $65.38 |
| High, 1,500 W, 24 h a day1,080 kWh a month | $144 | $130 | $196 |
Cost per 30-day month. EIA's state figure is the average price residential customers paid (revenue ÷ kWh sold), so it includes delivery charges. Your own utility's rate may differ.
Because prices were up 10.7% from a year earlier, the same 8-hour month on high went from $43.49 to $48.13. At the U.S. average it is $65.38.
What a whole winter costs
Most heaters only run part of the year. Four hours a day on high from November through March (150 days) uses 900 kWh, about $120 in Idaho at today's average price. The same season on low is about $72.20.
Ways to pay less
- Turn the central thermostat down while you use it. A space heater only saves money if it lets you heat one room instead of the whole home. DOE estimates up to 10% a year in heating savings from setting the thermostat back 7–10°F for 8 hours a day.
- Drop to low once the room is warm. 900 W instead of 1,500 W saves about $19.25 a month at 8 hours a day in Idaho.
- Use the timer. Left on around the clock, a heater on high would cost about $144 a month in Idaho. Many models have an auto-off timer.
- If electric heat is your main heat, price a heat pump. DOE says heat pumps can cut the electricity used for heating by about 50% compared with resistance heaters like space heaters and baseboards.
Safety. Plug space heaters straight into a wall outlet, never an extension cord or power strip, and keep them at least 3 feet from beds, curtains and furniture (CPSC).
More on heater types and wattage: what a space heater costs to run. A cheaper way to stay warm in bed: electric blanket costs.
Nearby states
Of the 8 states in the Mountain census division, Idaho is 6th most expensive for the same heater at 8 hours a day.
Questions
How much does it cost to run a space heater for an hour in Idaho?
A 1,500 W heater on high uses 1.5 kWh per hour. At Idaho's average residential price of 13.37¢/kWh (August 2026, U.S. EIA) that's about $0.20 per hour; on a 900 W low setting it's about $0.12.
How much does it cost to run a space heater all night in Idaho?
Eight hours on high is 12 kWh, about $1.60 a night or $48.13 over a 30-day month. Safety agencies (CPSC) advise not to leave a space heater running while you sleep; an electric blanket (about 100 W) costs roughly $0.11 for the same 8 hours.
How much does a space heater add to an electric bill in Idaho?
Running a 1,500 W heater 4 hours a day adds about $24.07 a month; 8 hours a day adds about $48.13; around the clock it's about $144. Use the calculator above with the rate from your own bill.
Has electricity gotten more expensive in Idaho?
EIA's average residential price in Idaho was 13.37¢/kWh in August 2026, up 10.7% from 12.08¢ in August 2025. The U.S. average moved from 17.57¢ to 18.16¢ (+3.4%).
Sources
- U.S. EIA, Electric Power Monthly, Table 5.6.A (residential sector), August 2026 and August 2025 (released October 23, 2026). Used for: Idaho and U.S. average residential prices
- U.S. CPSC: Staff Assessment on Portable Electric Heaters (Feb 2023). Used for: Plug-in heaters top out at 1,500 W
- Lasko 754200 ceramic heater, manufacturer specifications. Used for: Typical settings: 900 W low, 1,500 W high
- U.S. DOE: Energy Saver Guide (2022). Used for: Up to 10% heating savings from a 7–10°F setback; heat pumps use about 50% less electricity than resistance heat
- U.S. CPSC: Space heater safety warning. Used for: 3-foot clearance, wall outlet only, don't run while sleeping
Math: cost = watts × hours ÷ 1,000 × price per kWh; a month is 30 days. The state table is also available as a CSV, free to reuse with credit to WattCost.