Estimate electric fireplace running cost from watts, use time, electricity price, and thermostat cycling.
Table of contents
How to use our Electric Fireplace Running Cost Calculator
- Choose the Fireplace mode that best matches how you run the unit: flame only, low heat, high heat, or custom watts.
- Enter Power draw in watts, Hours used on each use day, and Electricity price in $ per kWh from your electric bill.
- Open Advanced options if you do not use it every day or if the heater cycles off part of the time, then adjust Use days each week and Power is on during fireplace use.
- Click Calculate to see Monthly cost after mode and cycling, plus cost per hour, cost per use day, yearly cost, monthly kWh, and average watts.
- Sanity-check the result: a 1500-watt heater at $0.16 per kWh should cost about $0.24 per hour at 100% on time, so a very different result usually means watts, hours, rate, or percent-on was entered wrong.
Definitions
Power draw: The electric power the fireplace uses while that setting is active, entered in watts.
Watt: A unit of electric power. A 1500-watt heater draws 1.5 kilowatts when running at full draw [1].
kWh: Kilowatt-hour, the energy used by 1 kilowatt running for 1 hour. Electric bills commonly charge by kWh [1].
Electricity price: The cost for each kWh. The most useful value is the all-in $ per kWh from your bill when available.
Power is on during fireplace use: The percent of use time when the entered Power draw is actually active. This models heater cycling.
Average power while running: The entered Power draw after the cycling percent is applied.
Common mistakes and quick fixes
Mistake: Using Fireplace mode as the final answer for wattage even when your model label says something else.
Fix: Pick the closest Fireplace mode, then edit Power draw to match the watts on your fireplace label or manual.
Mistake: Entering 1.5 in Power draw because the manual says 1.5 kW.
Fix: Convert kW to watts first, so 1.5 kW becomes 1500 in Power draw.
Mistake: Putting a monthly total in Hours used on each use day.
Fix: Enter the hours for one day when the fireplace is used, then set Use days each week for the schedule.
Mistake: Using only the energy supply charge for Electricity price and leaving out delivery charges that change with kWh.
Fix: Use your all-in Electricity price in $ per kWh when you can find it on the bill.
Mistake: Leaving Power is on during fireplace use at 100 when the thermostat turns the heater off often.
Fix: Lower Power is on during fireplace use to a reasonable estimate, such as 50 percent if the heater is drawing full power about half the time.
Limitations & Key Assumptions / Boundary Conditions
- The calculator uses a simple average electricity price. It does not model time-of-use rates, tiered rates, demand charges, taxes, or fixed monthly fees.
- Fireplace mode only fills a starter watt value. The Power draw you enter is the number used in the math.
- Power is on during fireplace use is an estimate. Real thermostat cycling changes with room size, insulation, set temperature, and outdoor temperature.
- Monthly results use an average month based on 52 weeks per year and 12 months per year, so a calendar month with more or fewer use days can differ.
- Yearly cost assumes the same Hours used on each use day and Use days each week for all 52 weeks.
- Fan-only, flame-only, low heat, and high heat settings can have different watt draws. Use the model label or manual when accuracy matters.
Methodology
How the cost is calculated
The calculator first converts Power draw from watts to kilowatts because electricity use is billed in kilowatt-hours, or kWh [1]. It then applies Power is on during fireplace use, which reduces average power when the heater cycles off during part of the run time.
power_kW = power_watts / 1000
average_power_kW = power_kW * (power_on_percent / 100)
cost_per_hour_of_use = average_power_kW * electricity_rate
cost_on_use_day = cost_per_hour_of_use * hours_per_day
monthly_hours = hours_per_day * days_per_week * 52 / 12
monthly_energy_kwh = average_power_kW * monthly_hours
monthly_cost_after_cycling = monthly_energy_kwh * electricity_rate
yearly_cost_after_cycling = average_power_kW * hours_per_day * days_per_week * 52 * electricity_rate
average_power_while_in_use = power_watts * (power_on_percent / 100)
Mini-example
For a 1500-watt fireplace used 4 hours per day, 7 days per week, at $0.16 per kWh with Power is on during fireplace use set to 50 percent, the adjusted average power is 750 watts, or 0.75 kW. The cost per hour is 0.75 * $0.16 = $0.12. Average monthly hours are 4 * 7 * 52 / 12 = 121.33 hours. Monthly electricity used is 0.75 * 121.33 = 91 kWh, and Monthly cost after mode and cycling is 91 * $0.16 = $14.56.