What the animation shows
The animation and the step-by-step video above use your numbers. Here is the same walkthrough written out for the default example.
What you enter
- Power draw: 1500 W.
- Hours used per day: 4.
- Days used per month: 30.
- Electricity rate: 0.17 $/kWh. Find this on your utility bill: total charges ÷ kWh used gives an all-in rate.
What happens, step by step
- 1,500 W running 4 hours a day uses 6 kWh.
- At $0.17 per kWh, each day of use costs $1.02.
- Each square is a day used: 30 days make 180 kWh a month.
- Twelve months of the same use add up to $367.20.
The answer: cost per month is $30.60.
How it’s calculated
- kWh per day = watts × hours ÷ 1,000
- Monthly kWh = daily kWh × days
- Cost = kWh × rate; yearly = monthly × 12
Worked example
A 1,500 W space heater, 4 hours a day, 30 days, at $0.17/kWh.
Inputs
- Power draw
- 1500 W
- Hours used per day
- 4
- Days used per month
- 30
- Electricity rate
- 0.17 $/kWh
Results
- Cost per month
- $30.60
- Cost per year
- $367.20
- Cost per day of use
- $1.02
- Energy per month
- 180 kWh
- Energy per day of use
- 6 kWh
Assumptions and limits
- Constant power while on. Time-of-use and tiered rates are not modelled.
Verify the result against the applicable local code, adopted code edition, manufacturer instructions and project requirements. See our methodology.
Questions
How much does a 1500 watt heater cost to run?
At $0.17/kWh it costs about $0.26 per hour, or $30.60 a month at 4 hours a day.
How do I find my electricity rate?
Divide the total on your bill by the kWh used. That all-in rate includes delivery charges.