What Is the Space Heater Running Cost Calculator?
This calculator estimates how much it costs to run an electric space heater. Enter the heater wattage, how many hours per day you use it, and your electricity price per kilowatt-hour (kWh). It returns the cost per hour, per day and per month so you can budget your winter heating bill. It works in any country — just enter your local electricity rate in your own currency.
How to Use It
1. Find the wattage on the heater label or manual (most plug-in heaters are 750–1500 W). 2. Enter the hours you run it each day. 3. Enter your electricity tariff per kWh (check a recent utility bill). The results update instantly.
The Formula Explained
Electricity is billed in kilowatt-hours. One kWh is 1000 watts running for one hour. The core formula is:
$$\text{Cost} = \frac{\text{Watts}}{1000} \times \text{Hours} \times \text{Rate}$$
Dividing watts by 1000 converts to kilowatts. Multiplying by hours gives energy in kWh. Multiplying by your rate gives the cost. Daily cost uses hours per day; monthly cost multiplies the daily figure by 30 days.
Worked Example
A 1500 W heater run 5 hours a day at a rate of $0.20 per kWh: energy per day = \( \frac{1500}{1000} \times 5 = 7.5 \) kWh. Daily cost = \( 7.5 \times 0.20 = \$1.50 \). Hourly cost = \( \frac{1500}{1000} \times 0.20 = \$0.30 \). Monthly cost = \( \$1.50 \times 30 = \$45.00 \).
FAQ
Does a thermostat reduce these costs? Yes. Heaters with a thermostat cycle off once the target temperature is reached, so real-world cost is often lower than this full-power estimate.
Are all space heaters 100% efficient? Practically yes — nearly all electrical energy becomes heat, so a 1500 W heater delivers about 1500 W of heat regardless of type.
What rate should I use? Use your marginal electricity price per kWh from your latest bill, including any per-kWh delivery charges.
