Space Heater Running Cost Calculator
Enter the wattage on your heater label, your actual schedule and your electric rate to estimate electricity use and cost.
The short answer
Free calculator
Calculate your heater's running cost
Your inputs
Use the heater label and your latest utility bill.
Enter the rated wattage shown on your heater label.
Use decimals for partial hours, such as 2.5.
17¢ is illustrative. Your bill is the best source.
Your estimate
Electricity cost
- Per hour
- $0.26
- Per day (4 hr)
- $1.02
- Per week (7 days)
- $7.14
- Per month
- $30.94
6.00 kWh/day and approximately 182.0 kWh/month at the schedule entered.
This does not predict thermostat cycling, changing rates, taxes or fixed utility fees.
Calculation shown
(1,500W ÷ 1,000) × 4 hours × 17¢ per kWh = $1.02 per day
Optional. Compare equivalent periods only; this is not a savings promise.
How is space heater cost calculated?
Convert watts to kilowatts by dividing by 1,000. Multiply that figure by hours of use, then multiply by the electricity price per kWh. Weekly cost also uses the days-per-week input. Monthly cost uses 52 weeks divided by 12, or about 4.33 weeks per month.
| Rated input | One hour | Four hours | 30 days at 4 hr/day |
|---|---|---|---|
| 500W | $0.09 | $0.34 | $10.20 |
| 1,000W | $0.17 | $0.68 | $20.40 |
| 1,500W | $0.26 | $1.02 | $30.60 |
Which electricity rate should you enter?
Check the energy or supply price on your latest bill, usually shown in cents per kWh. Include delivery charges only when they rise with each kWh used. Leave out fixed customer, account or meter fees because running the heater does not create those charges. If your rate changes by time of day, use the rate that applies when the heater normally runs.
Key takeaway
What can make the actual bill different?
- The heater's measured draw may differ by mode or setting.
- A thermostat may pause or reduce heating after the set temperature is reached.
- Drafts, insulation, room volume and outdoor temperature affect active heating time.
- Time-of-use, tiered and seasonal rates can change the price during the month.
- Taxes and utility adjustments may appear separately from the energy rate.
A plug-in electricity monitor can measure actual kWh for a compatible appliance, but use only equipment rated for the heater's electrical load and follow both manufacturers' instructions.
Recommended in this guide
The compact heater this guide keeps coming back to
RapidHeat is a portable ceramic fan heater for personal and supplemental room heating. Room results depend on insulation, drafts, ceiling height and starting temperature; it is not a whole-home heating replacement.
- Ceramic fan heating
- Remote control included
- Programmable timer
When can zone heating reduce total cost?
A portable heater can reduce total heating cost when it warms one occupied room and you lower central heating elsewhere. Adding a heater while leaving the central system unchanged adds electricity use instead. Building efficiency, fuel prices and heating-system performance determine the real comparison.
Use the optional comparison above only with equivalent periods and comfort goals. For a fuller decision framework, read our space heater vs central heating comparison.
Use any portable heater safely
Plug a portable heater directly into a suitable wall outlet, keep combustible items at least three feet from the heater, and switch it off before sleeping or leaving the room. Follow the product label and manual. Stop using a heater or outlet that becomes damaged, discolored or unusually hot.
Space heater cost calculator FAQs
How accurate is this space heater cost calculator?
The arithmetic is accurate for the wattage, schedule and electricity rate entered. Your bill can differ because a heater may cycle on and off, draw differently by setting, and face changing utility rates, taxes or fees.
Where do I find my electricity rate?
Use the energy or supply price shown in cents per kilowatt-hour on your latest electric bill. If your utility separates supply and delivery charges that both vary with usage, include both. Do not divide fixed monthly account fees into the rate unless you intentionally want a blended whole-bill estimate.
Does a thermostat lower a space heater's running cost?
It can. After a room reaches the set temperature, some heaters reduce or pause active heating. The effect cannot be predicted from wattage alone because room size, drafts, insulation, outdoor temperature and the chosen setting all matter.
Is a space heater cheaper than central heat?
Sometimes, when it lets you heat one occupied room while reducing central heat elsewhere. It may cost more if you run it without lowering central heat. Compare costs for the same hours and comfort goal rather than assuming a saving.
How much does a 1,500-watt heater cost per hour?
At 17 cents per kWh, the input-based estimate is about 26 cents per hour: 1.5 kW multiplied by $0.17. Enter your own utility rate because prices vary by location and rate plan.
Why buy direct from RapidHeat US
- Official US store — the same team that handles warranty claims
- Free shipping to eligible US delivery addresses
- 30-day return window and a 12-month limited warranty
- US-based email and phone support, not a marketplace reseller
Sources & how we got these numbers
- US Energy Information Administration — Electric Power Monthly — US residential electricity-price reporting used for the rounded illustrative default
- Department of Energy — Small Space Heaters — portable heater selection, efficiency and zone-heating guidance
- National Fire Protection Association — Heating Safety — portable heater placement and operating safety guidance
Costs are illustrative and calculated at the US average residential electricity rate. Your own rate, room and usage will change the result. See our editorial standards.
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