Space Heater Cost Calculator
Find out how much it really costs to run a space heater. Enter your heater type, daily usage, and electricity rate to see your cost per hour, day, month, and full winter season.
Your Heater Setup
Check your electric bill for your exact rate.
Your Heating Costs
Monthly Cost
$57.60
1 heater · 12.0 kWh/day
Per Hour
$0.24
Per Day
$1.92
Winter Season (5 mo)
$288
Full Year
$691
Space Heater vs Heat Pump
Heat pumps are ~3x more efficient than space heaters for the same amount of heat.
A heat pump would save ~$38/month for the same heat output.
Space Heater Tips
- Zone heating: Heat only the room you're in and turn off heat in empty rooms.
- Close doors: Keep heated rooms closed to retain warmth.
- Lower thermostat: Drop central heat 5-10°F when using a space heater.
- Safety first: Keep 3 feet of clearance and never leave unattended.
- Consider a heat pump: 3x more efficient for whole-room heating.
How to Calculate Space Heater Running Cost: Step-by-Step
Space heaters are convenient but can be expensive to run. Calculating the actual cost helps you decide when they make financial sense versus other heating options.
Step 1: Check the Heater Wattage
Look at the label on the heater for the wattage rating. Most portable space heaters are 750W (low setting) or 1,500W (high setting). Some oil-filled radiators and ceramic heaters have variable settings between 500W and 1,500W.
Step 2: Determine Daily Hours of Use
Estimate how many hours per day you run the heater. A home office might need 8 hours during the workday. A bedroom might need 4-6 hours at night. Be honest about usage to get an accurate cost estimate.
Step 3: Convert Watts to Kilowatts
Divide the wattage by 1,000: 1,500W / 1,000 = 1.5 kW. If your heater cycles between settings, estimate the average. A heater on "auto" at 1,500W that cycles 75% of the time effectively uses about 1.125 kW.
Step 4: Calculate Monthly kWh
Multiply kW by hours per day by 30 days: 1.5 kW x 8 hours x 30 = 360 kWh per month. That is a significant addition to your electricity bill, equivalent to running a large refrigerator for 3 months.
Step 5: Multiply by Your Electricity Rate
Multiply monthly kWh by your rate: 360 kWh x $0.15 = $54.00 per month. Compare this to the cost of raising your central thermostat. In many cases, it is cheaper to heat the whole house a degree or two higher than to run a space heater.
Formula
Monthly Cost = (Watts / 1,000) x Hours/Day x 30 x Rate/kWh
Where: Watts = Heater rating (typically 750W or 1,500W), Hours/Day = Daily usage, Rate = Your electricity cost per kWh
Worked Example
Scenario: Calculate the monthly cost of a 1,500W space heater running 8 hours per day at $0.15/kWh.
- Step 1: Heater wattage = 1,500W (high setting)
- Step 2: Daily usage = 8 hours (home office)
- Step 3: Kilowatts = 1,500 / 1,000 = 1.5 kW
- Step 4: Monthly kWh = 1.5 x 8 x 30 = 360 kWh
- Step 5: Monthly cost = 360 x $0.15 = $54.00
Result: The space heater costs $54.00 per month, or $1.80 per day, to run 8 hours on the high setting.
Space Heater Running Costs by Type
Below are the running costs for common space heater types at different usage levels, using the US average electricity rate of $0.16/kWh. Your costs may be higher or lower depending on your local rate.
| Heater Type | Watts | Cost/Hour | Cost/Day (8 hrs) | Cost/Month | Winter (5 mo) |
|---|---|---|---|---|---|
| Personal Heater | 750W | $0.12 | $0.96 | $28.80 | $144 |
| Baseboard (4 ft) | 1000W | $0.16 | $1.28 | $38.40 | $192 |
| Ceramic Heater | 1500W | $0.24 | $1.92 | $57.60 | $288 |
| Oil-Filled Radiator | 1500W | $0.24 | $1.92 | $57.60 | $288 |
| Infrared Heater | 1500W | $0.24 | $1.92 | $57.60 | $288 |
| Fan-Forced Heater | 1500W | $0.24 | $1.92 | $57.60 | $288 |
| Baseboard (8 ft) | 2000W | $0.32 | $2.56 | $76.80 | $384 |
Costs calculated at $0.16/kWh (US average) and 8 hours/day usage. Winter season assumes 5 months (November–March). Actual costs vary by electricity rate and thermostat cycling.
Frequently Asked Questions
How much does it cost to run a space heater per hour?
A typical 1,500-watt space heater costs about $0.24 per hour to run at the US average electricity rate of $0.16/kWh. That's $1.92 for 8 hours, or about $57.60 per month if you run it 8 hours daily. The exact cost depends on your local electricity rate. In California ($0.27/kWh), the same heater costs $0.41/hour.
How much does a space heater cost per month?
Running a 1,500W space heater for 8 hours per day costs approximately $50-60 per month at average US electricity rates. If you run it 24/7 (not recommended for safety reasons), costs jump to $170-180/month. Running multiple heaters in different rooms can easily add $100-200+ to your monthly electric bill.
Is it cheaper to use a space heater or central heat?
It depends on how many rooms you need to heat. A space heater is cheaper if you're only heating one room while keeping the rest of the house cooler. However, heating 3+ rooms with space heaters is almost always more expensive than central heating. A modern heat pump is about 3x more efficient than a space heater. The break-even point is usually 2-3 rooms. Beyond that, central heat wins.
Do all space heaters cost the same to run?
Yes, virtually all electric space heaters cost the same to run at the same wattage. A 1,500W ceramic heater, oil-filled radiator, and infrared heater all use 1,500 watts and produce the same amount of heat. The difference is in how they distribute heat: ceramic heaters warm up quickly, oil radiators retain heat longer, and infrared heaters warm objects directly. Choose based on comfort preference, not energy savings.
How much does a 1500 watt heater add to the electric bill?
A 1,500W heater running 8 hours per day adds about $1.92/day or $57.60/month to your electric bill at the US average rate of $0.16/kWh. Over a 5-month winter season, that's approximately $290. In high-rate states like California or Connecticut, the same heater adds $80-100/month.
Are oil-filled radiators cheaper to run than ceramic heaters?
No. At the same wattage, they cost exactly the same to run. Both a 1,500W oil-filled radiator and a 1,500W ceramic heater use 1,500 watts of electricity. Oil-filled radiators do retain heat for 20-30 minutes after being turned off, so they may cycle on and off less with a thermostat. In practice, the cost difference is negligible.
Can a space heater catch fire?
Space heaters are involved in about 1,700 home fires per year in the US according to the NFPA. To reduce risk: keep at least 3 feet of clearance from anything flammable, never use extension cords (plug directly into a wall outlet), choose heaters with tip-over shutoff and overheat protection, never leave a heater running while you sleep or leave the room, and never use a heater to dry clothes.
What size space heater do I need for my room?
The general rule is 10 watts per square foot for a standard room with 8-foot ceilings. A 1,500W heater can effectively heat a 150 sq ft room (roughly 10x15 feet). For larger rooms, you'll need multiple heaters or a higher-wattage unit. For well-insulated rooms, you may need less. For poorly insulated rooms or those with high ceilings, you may need more.
Should I use a space heater at night?
Running a space heater while sleeping is generally not recommended due to fire risk and carbon monoxide concerns (for fuel-burning heaters). If you must use one at night, choose an oil-filled radiator (no exposed element, retains heat), ensure it has tip-over and overheat shutoff, and place it at least 3 feet from bedding. A programmable thermostat that turns the heater off after you fall asleep is the safest approach.
How much does it cost to run a space heater all winter?
Running a 1,500W space heater for 8 hours per day over a 5-month winter season (November through March) costs approximately $290 at the US average rate. Running it 12 hours per day pushes that to $430. If you use two heaters, double those numbers. For exact costs in your area, use the calculator above and enter your local electricity rate.
Managing Your Heating Costs
Space heaters can be a cost-effective supplement to central heating when used strategically in one or two rooms. However, they quickly become expensive when heating an entire home. To understand how space heater costs fit into your total energy picture, use our Electricity Bill Calculator to estimate your full monthly electric bill.
Curious how much other appliances add to your bill? The Appliance Cost Calculator lets you check the running cost of any household device, from refrigerators and dryers to gaming PCs and hot tubs.
If you're thinking about upgrading to a heat pump or adding electric baseboard heaters permanently, make sure your electrical panel can handle the load. Our Breaker Size Calculator helps you find the right breaker and wire gauge for any appliance.
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