Space Heater Cost Calculator

About the Space Heater Cost Calculator

Space heaters are one of the most energy-hungry appliances in any home. A typical portable electric heater runs at 1,500 watts — the maximum for a standard 15-amp outlet in the US. Running that heater for 8 hours costs $1.20–$1.80 per day depending on your electricity rate, which can add $35–$55 to your monthly bill.

Despite this, space heaters can be cost-effective when used strategically. Heating a single room with a space heater while lowering the central thermostat by 5–10 degrees can save money overall, since you're only heating the space you're actually using. The key is understanding the true running cost.

This calculator shows you the hourly, daily, monthly, and annual cost of running any electric space heater. Whether you have a ceramic, oil-filled, infrared, or fan-forced heater, the math is the same: watts times hours divided by 1,000 times your rate.

Precise measurement of this value supports sustainable energy planning and helps organizations reduce their environmental impact while maintaining operational performance and comfort levels.

When This Page Helps

Space heaters can either save or waste money depending on how you use them. This calculator reveals the exact cost so you can make informed decisions about zone heating vs central heating. Regular monitoring of this value helps energy teams detect usage anomalies early and address equipment malfunctions or operational issues before they drive utility costs higher.

How to Use the Inputs

1. Check the wattage rating on your space heater (typically 750W or 1,500W).
2. Enter the wattage into the calculator.
3. Enter how many hours per day you plan to run it.
4. Enter your electricity rate per kWh.
5. View the cost per hour, per day, per month, and per year.
6. Compare against the cost of running your central heating system.

Example Calculation

Tips & Best Practices

• Use the low setting (750W) when possible — it cuts energy cost in half.
• Place the heater near where you sit, not in the center of a large room.
• Close doors to the heated room to prevent heat loss.
• Use a thermostat-equipped heater that cycles off when the room reaches temperature.
• Never use extension cords with space heaters — plug directly into the wall outlet.
• Compare the cost of running a space heater to turning up your central heat by a few degrees.

Understanding Space Heater Wattage

Most portable space heaters have two settings: 750W (low) and 1,500W (high). The high setting is designed for a 15-amp circuit and draws the maximum safe continuous load. Some heaters offer 500W, 1,000W, or 1,500W settings for more flexibility.

Zone Heating Strategy

The most cost-effective way to use a space heater is "zone heating": heat only the room you're in while lowering your central thermostat by 5–10°F. This strategy works best in large homes where central heating wastes energy on unoccupied rooms. The savings depend on your home size, insulation, and climate.

Space Heater vs Heat Pump

An electric space heater produces 1 unit of heat per unit of electricity (COP = 1.0). A heat pump produces 2–4 units of heat per unit of electricity (COP = 2–4). If you're supplementing heat frequently, a ductless mini-split heat pump may be more economical despite the higher upfront cost.

Frequently Asked Questions

• How much does a space heater cost to run per hour?

  At 1,500 watts and $0.14/kWh, a space heater costs about $0.21 per hour. On the low (750W) setting, it costs about $0.105 per hour. Your actual cost depends on your specific electricity rate.

• Is it cheaper to use a space heater or central heat?

  It depends. If you're heating one or two rooms in a large house, a space heater plus lowering the thermostat can save money. But running multiple space heaters to heat an entire home is almost always more expensive than central heating.

• What type of space heater is most efficient?

  All electric space heaters convert electricity to heat at nearly 100% efficiency, so the "type" matters less than you might think. The difference is in heat distribution: oil-filled radiators provide steady warmth, ceramic heaters heat quickly, and infrared heaters warm objects directly.

• Can a space heater raise my electric bill significantly?

  Yes. Running a 1,500W heater 8 hours/day for 30 days adds about 360 kWh to your monthly usage, costing $40–$60 at typical rates. That can increase a $120 monthly bill by 30–50%.

• Are space heaters safe to leave on overnight?

  Modern space heaters with tip-over protection and overheat shutoff are relatively safe, but fire safety experts generally recommend turning them off when sleeping or leaving the room. Never drape anything over a heater or place it near flammable materials.

• Why are most space heaters 1,500 watts?

  1,500 watts is the maximum load for a standard US 15-amp, 120-volt outlet (15A × 120V = 1,800W, with 80% continuous load = 1,440W, rounded to 1,500W). This is a safety limit set by electrical code, not a manufacturer choice.