How Much Does It Cost to Run an Electric Heater?

Electric heaters offer a way to warm specific areas within a home, providing comfort without activating a central heating system. Many individuals consider these devices for supplemental warmth, leading to questions about their operational expense. Estimating the cost of running an electric heater involves a straightforward approach that accounts for several measurable factors.

Understanding the Core Calculation

Calculating the cost of operating an electric heater relies on a fundamental formula: Kilowatts (kW) x Hours of Use x Cost per Kilowatt-hour (kWh). This formula quantifies energy consumption and applies the associated rate.

A kilowatt is 1,000 watts. A kilowatt-hour is a unit of energy, signifying the consumption of one kilowatt of power over one hour. Utility companies bill for electricity based on kilowatt-hours consumed.

Key Variables Determining Cost

The first variable is the heater’s power rating, typically expressed in watts (W). This rating is usually found on the heater itself. To convert watts to kilowatts for the cost calculation, divide the wattage by 1,000; for example, a 1,500-watt heater is 1.5 kilowatts.

The second variable is the electricity rate, which represents the cost per kilowatt-hour (kWh) and is found on your monthly utility bill. This rate can vary significantly based on your geographical location and electricity plan. The average residential electricity rate in the United States was around 17.47 cents per kWh in August 2025.

The final variable is the duration of use, measured in hours. This refers to the actual time the electric heater is actively drawing power. Several factors influence how long a heater needs to run to achieve and maintain a desired temperature, directly impacting total hours of operation and cost:

• Room size
• Insulation quality
• Desired temperature setting
• External ambient temperature

Practical Cost Estimation and Scenarios

To illustrate, consider a common 1,500-watt electric heater (1.5 kilowatts). If the average electricity rate in your area is $0.17 per kilowatt-hour, running this 1.5 kW heater for one hour costs 1.5 kW x 1 hour x $0.17/kWh, totaling $0.255 per hour.

For occasional use, if this 1.5 kW heater is used for four hours a day in a home office for 30 days, total operating hours are 120 (4 hours/day x 30 days). The monthly cost would then be 1.5 kW x 120 hours x $0.17/kWh, amounting to $30.60.

In a different scenario, consider a smaller 750-watt heater (0.75 kW) used for eight hours daily in a bedroom. Over a 30-day month, this heater would operate for 240 hours (8 hours/day x 30 days). At the same $0.17/kWh rate, the monthly cost would be 0.75 kW x 240 hours x $0.17/kWh, resulting in $30.60.