Rex says
Money math without the spreadsheet headache. Plug in your numbers and I'll show you exactly where the dollars land.
Try a scenario
Click to load — tweak from there.Inputs
Result
Cost per day
$1.92
Cost per month
$57.60
Cost for a 120-day season
$230.40
Psst — share this and help Rex grow
One click, a permanent link with your numbers baked in.
How to use this
- 1Enter heater wattage (W).
- 2Enter hours used per day (hrs).
- 3Enter electricity rate ($/kWh).
- 4Read your cost per day on the right — it updates as you type.
- 5Hit Share to keep the scenario or send it to someone.
About this calculator
Electric heater running cost is a straightforward wattage-to-kilowatt-hour conversion: multiply the heater's wattage by hours used to get watt-hours, convert to kilowatt-hours, and multiply by your electricity rate. This calculator gives you daily, monthly, and seasonal costs.
Worked example
Using the values the calculator loads with:
Inputs
- Heater wattage: 1500 W
- Hours used per day: 8 hrs
- Electricity rate: 0.16 $/kWh
Results
- Cost per day: $1.92
- Cost per month: $57.60
- Cost for a 120-day season: $230.40
What each field means
Inputs
- Heater wattage (W)
- The heater wattage used in the calculation, measured in W. Starts at 1500 W so you have a working example on load. Accepted range: 100–5000 W.
- Hours used per day (hrs)
- The hours used per day used in the calculation, measured in hrs. Starts at 8 hrs so you have a working example on load. Accepted range: 0–24 hrs.
- Electricity rate ($/kWh)
- The electricity rate used in the calculation, measured in $/kWh. Starts at 0.16 $/kWh so you have a working example on load. Accepted range: 0.05–0.5 $/kWh.
Results
- Cost per day
- Returned as a money amount in US dollars and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Cost per month
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Cost for a 120-day season
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
How much does it cost to run a space heater?
A 1,500-watt heater run 8 hours a day at 16¢/kWh uses 12 kWh a day, costing about $1.92/day, or roughly $57.60 over a 30-day month.
How much does wattage affect the cost?
Cost scales linearly with wattage — a 750-watt heater costs half as much to run as a 1,500-watt one for the same hours, which matters a lot if you're heating just one small room.
Is a space heater cheaper than central heating?
It depends on how many rooms you're heating — running one space heater in a single occupied room is often cheaper than heating an entire house, but running several space heaters can exceed central heating costs.
How can I lower the cost?
Use a thermostat-controlled model to avoid overheating, only run it in occupied rooms, and check your local off-peak electricity rates if your utility offers time-of-use pricing.
Accuracy and limitations
- Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
- Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.
- This is educational maths, not financial advice. Check anything contractual with the lender or your accountant.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). How Much Does It Cost to Run a Space Heater?. Retrieved from https://www.revenuelab.fyi/toolbox/how-much-to-run-a-space-heater
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/how-much-to-run-a-space-heater" target="_blank" rel="noopener">How Much Does It Cost to Run a Space Heater? — RevenueLab</a> (2026).</p>
Source: [How Much Does It Cost to Run a Space Heater? — RevenueLab](https://www.revenuelab.fyi/toolbox/how-much-to-run-a-space-heater) (2026).