Why the space heater running cost calculator matters
Space heaters are cheap to buy and expensive to run, and they only make financial sense when they let you turn the whole-house thermostat down rather than adding to it. This page turns that decision into a handful of inputs you can defend in a budget review: volume, unit cost, rate of adoption, and time. The output is a planning baseline, not a promise — it tells you whether the idea deserves a vendor quote, a pilot, or a pass.
- • Biggest swing factor: hours run per day, the dominant factor
- • Second-order factor: heater wattage, usually 750W or 1,500W
- • Often ignored: your electricity price
What actually changes the answer
hours run per day, the dominant factor moves this number first, then heater wattage, usually 750W or 1,500W. Run a conservative case and an upside case before you commit. If the maths only works in the upside case, treat it as a time-boxed test with a kill date rather than a line in next year's plan.
What to do with the result
Use it to heat one occupied room while lowering the central thermostat by a few degrees — that is the only configuration that saves money.
FAQ
What does the space heater running cost calculator work out?
It applies Monthly cost = units × cost per unit + fixed charge; 12-month cost compounds any growth rate you set to the values you enter for monthly kwh the heater uses, electricity price per kwh ($), any fixed monthly cost ($), monthly energy price drift. Space heaters are cheap to buy and expensive to run, and they only make financial sense when they let you turn the whole-house thermostat down rather than adding to it.
How accurate is this space heater running cost calculator?
Energy arithmetic on the usage you enter. Thermostatic heaters cycle, so real usage is often below the maximum. Replace the defaults with your own invoice, usage export, payroll data, statement, or vendor quote before making a commitment — the maths is exact, so the answer is only as good as the inputs you feed it.
Which input should I stress-test first?
hours run per day, the dominant factor. Re-run with a pessimistic value for it; if the decision flips, that assumption is the thing you need real data on before signing anything. After that, check heater wattage, usually 750W or 1,500W and your electricity price.
Which scenario should I start from?
Start with the preset closest to your situation — lean month, typical month, heavy month — then edit the sliders. Presets are realistic starting points, not benchmarks to match, and every change updates the result instantly.
What should I do after running the numbers?
Use it to heat one occupied room while lowering the central thermostat by a few degrees — that is the only configuration that saves money. A useful planning benchmark to compare against: A 1,500W space heater costs roughly $0.25 an hour at $0.17/kWh — about $30 a month at four hours a day.
Can I share or save this calculation?
Yes. Your inputs are written into the page URL, so copying the link shares the exact scenario you are looking at — the person who opens it sees the same numbers. You can also export the inputs and results to CSV or PDF from the result card and keep it with the rest of your workings.
How this calculator is built
Independently maintained
Written by Sam Doshi and the RevenueLab editorial team. We don't sell the data feeds this tool is built on.
Sourced from primary data
Benchmarks come from public AdSense / Stripe / IRS disclosures and reader-submitted data — never third-party "$X per view" claims. Full methodology.
Last editorial review
Reviewed on a rolling quarterly cycle. Dated reviews are published on the methodology record for each calculator.
Editorial standards
See our editorial policy and disclaimer. Results are estimates, not advice.