How much does it cost to run a 1,500-watt space heater?

At the US average rate of about $0.17/kWh, a 1,500 W heater costs roughly $1.43 a day, or about $43 a month, when a thermostat keeps it running about 70% of the time. Left running flat out with no cycling, the same heater climbs to about $61 a month. Over a 150-day heating season at the typical duty cycle, that adds up to around $214. Because the rate does most of the work, enter your own number from a recent bill rather than the national average.

Is it cheaper to run a space heater or central heating?

It depends on how much of the house you are heating. A space heater only saves money when you are zone heating, warming one occupied room while the central system is turned down or off. In that case a single 1,500 W heater at about $43 a month can cost less than running a furnace for the whole house. But heat two or three rooms with separate space heaters and the total usually passes what central heat would have cost, because you are no longer concentrating the warmth where you actually are.

Do space heaters use a lot of electricity?

Yes, a 1,500 W heater is one of the largest plug-in loads in a typical home, on par with a countertop microwave or a hair dryer, but running for hours rather than minutes. That combination of high wattage and long run time is what makes it expensive, not the wattage alone. A television or laptop draws a fraction as much and can run all evening for pennies. The heater is costly because heat itself is energy-intensive to produce with electricity.

Does a lower setting or a smaller space heater save money?

Yes, and close to proportionally. Heat output tracks wattage almost directly, so a 750 W low setting costs about half what the 1,500 W high setting costs for the same run time, roughly $21 a month against $43 at typical use. The only question is whether the lower output still keeps the room comfortable; if it does, the saving costs nothing. An oil-filled radiator on a low setting holds heat longer between cycles, which can stretch the saving further without feeling colder.

Does this calculator work for gas or propane space heaters?

No, it covers electric-resistive heaters only, the plug-in kind rated in watts. Gas, propane, and kerosene heaters burn fuel, so their running cost depends on the price of a therm or a gallon and the unit’s combustion efficiency, not on a per-kWh electricity rate. Comparing the two fairly means converting both to cost per unit of heat delivered, which is a different calculation. For an electric heater, though, the watts-to-cost math here is exact, because resistive heat is close to 100% efficient at the point of use.

Space Heater Cost Calculator — Winter Run Cost

7 min read

The space heater cost calculator turns three numbers — the heater’s wattage, how many hours a day it runs, and your electricity rate — into a real dollar figure per day, month, and full heating season. It covers electric-resistive heaters, the plug-in 750 to 1,500 W kind (ceramic, fan, oil-filled radiator, infrared), which the U.S. DOE rates as 100% efficient at the point of use, so nameplate watts are the heat output with no efficiency rating to look up. It does not cover gas, propane, or kerosene heaters, which run on fuel cost rather than a kWh rate. Two things move the result more than anything else, and both are yours to set: enter your own rate instead of a national average, and set how often the thermostat lets the element rest, because a heater that idles once the room is warm costs far less than one running flat out. For the summer side of the bill, the air conditioner cost calculator does the same job for cooling.

Space heater running cost banner: about $43 a month at 70% thermostat duty and $214 for a 150-day winter.

Why a Space Heater Is One of the Priciest Things You Plug In

An electric space heater turns nearly every watt it draws into heat, which sounds efficient, and at the point of use it is. The catch is the sheer size of the load. A 1,500 W heater sits right at the ceiling for a standard 120-volt outlet: at 12.5 amps it uses most of a 15-amp circuit on its own, which is why running one on an extension cord or sharing the circuit with other loads is a common cause of tripped breakers and overheated cords. That same 1,500 W is more than ten typical LED bulbs, a laptop, and a television running together.

Because resistive heat has no efficiency rating to shop for — every brand converts watts to heat at the same rate — the only levers on cost are how many watts you draw, how long it runs, and how often the thermostat lets it rest. For a single reading on any device where you already know the wattage, the electricity cost calculator takes watts directly; this page adds the heater-specific duty cycle and heating-season framing on top.

Space heater monthly running cost by thermostat duty cycle, from about $31 at 50% to $61 at 100% continuous. — Estimates assume 1,500 W at 70% thermostat duty, 8 hrs/day, and $0.17/kWh — electric-resistive heaters only. Real cost shifts with your rate, how often the thermostat cycles, and how well the room holds heat.

What a Space Heater Costs at Each Wattage Setting

Most heaters offer two or three settings. The table below runs the common ones through the same assumptions — a 70% thermostat duty cycle, 8 hours a day, and $0.17/kWh — so the only variable is the wattage you select.

Setting	Avg Draw (70% duty)	Monthly Cost*	Season Cost*
750 W (low)	525 W	$21.42	$107.10
1,000 W (medium)	700 W	$28.56	$142.80
1,500 W (high)	1,050 W	$42.84	$214.20

*At 8 hrs/day, 70% duty, and $0.17/kWh over a 150-day season. The pattern is linear: the low setting costs almost exactly half the high setting, because heat output tracks wattage directly. If the smaller output still keeps the room comfortable, the low setting is free money. To see how a heater ranks against the other big loads in the house, the appliance electricity cost calculator sorts them by annual cost.

Space Heater vs Heat Pump vs Central Heat

A space heater looks cheap because it is: $20 to $80 to buy, nothing to install. The running cost is where it catches up with you. The most useful comparison is not against another space heater but against the alternatives for the same warmth.

Versus central heating. If you are heating the whole house anyway, a space heater on top adds cost rather than saving it. The space heater only wins when you are zone heating, keeping one occupied room warm while the central system is turned down or off. In that narrow case, one 1,500 W heater at about $43 a month can undercut running a furnace for the whole house. Heat two or three rooms this way and the math flips back the other way.

Versus a heat pump. A ductless mini-split heat pump moves heat instead of generating it, so it delivers the same warmth for far less electricity. The U.S. DOE’s guidance on electric resistance heating notes a heat pump cuts electricity use by about half compared with a resistance heater. A heat pump costs $1,500 to $3,000 installed, but for a room you heat every day it usually pays back in a few winters. For a whole-home efficiency picture across heating, cooling, and water heating, the electricity bill estimator builds the full monthly total.

Worked Examples

A 1,500 W Office Heater Through the Winter

Context

You run a 1,500 W ceramic space heater in a home office 8 hours a day. A built-in thermostat holds the room at a comfortable temperature, so the element actually draws power about 70% of that time. Your electricity rate is $0.17/kWh, and the heating season runs roughly 150 days (November through March). What does the heater add to the bill?

Calculation

Average draw: 1,500 W × 70% = 1,050 W

Daily energy: 1,050 W × 8 h ÷ 1,000 = 8.4 kWh

Daily cost: 8.4 kWh × $0.17 = $1.43

Monthly cost: 8.4 kWh × 30 × $0.17 = $42.84

Full season (150 days): 8.4 kWh × 150 × $0.17 = $214.20

Interpretation

About $43 a month, or $214 for the winter, from a single heater. Run a second one in another room and it doubles. If the thermostat never cycled and the element ran flat out, the same heater would cost about $61 a month instead of $43, which is why the duty-cycle figure matters more than the wattage printed on the box.

Takeaway

Heating a room off-grid changes the stakes: 1,050 W is a heavy continuous draw for a battery bank. Drop that figure into the battery runtime calculator to see how quickly it flattens a typical bank — the answer is usually a couple of hours, not overnight.

The Same Heat for Less on a 750 W Low Setting

Context

Instead of the high setting, you run the same heater on its 750 W low setting to take the chill off a small, well-sealed room. It stays on continuously (no thermostat cycling) for 6 hours each evening across the 150-day season at $0.17/kWh. How does the cost compare?

Calculation

Average draw: 750 W × 100% = 750 W

Daily energy: 750 W × 6 h ÷ 1,000 = 4.5 kWh

Daily cost: 4.5 kWh × $0.17 = $0.77

Monthly cost: 4.5 kWh × 30 × $0.17 = $22.95

Full season (150 days): 4.5 kWh × 150 × $0.17 = $114.75

Interpretation

Roughly half the cost of the high-setting example above, about $115 across the winter. Halving the wattage roughly halves the bill, so if a lower setting keeps the room comfortable it is the simplest saving available, with no new equipment and no thermostat math.

Takeaway

Planning to run heat from solar and batteries instead of the grid? Total the heater against your other loads in the off-grid load calculator before sizing an array — resistive heat is the single load most likely to blow an off-grid power budget.

Frequently Asked Questions

Glossary

Thermostat Duty Cycle

The share of on-time a heater’s element actually draws power. A thermostat cuts the element off once the room reaches temperature, then restarts it as the room cools, so a heater switched on for 8 hours might only draw power for 5 or 6 of them. Duty cycle is the largest source of real-world cost variation: the same heater costs far less in a warm, well-insulated room than in a cold, draughty one.

Resistive Heating

Heat produced by passing current through a high-resistance element, as in a ceramic, fan, oil-filled, or infrared space heater. It is close to 100% efficient at the point of use, meaning the nameplate wattage equals the heat output, with no efficiency rating to compare. This is why every electric-resistive heater of the same wattage costs the same to run.

Heating Season

The stretch of the year a space heater is in use, often November through March, or about 150 days in much of the US. Running cost scales directly with season length, so a longer or colder winter multiplies the total. The season total is usually the number people mean when they ask what a heater costs to run.

Kilowatt-Hour (kWh)

A unit of energy equal to 1,000 watts drawn for one hour. It is what the utility bills for, and it is the bridge between a heater’s wattage and its cost: watts times hours divided by 1,000 gives kWh, and kWh times your rate gives dollars.

A space heater is usually a winter spike on top of a baseline — our household energy-audit guide shows how to find every load that matters, biggest first.

The honest bottom line: a space heater’s running cost is set by how you use it, not by the badge on the box. Every electric-resistive heater converts watts to heat the same way, so the wattage you choose, the hours you run it, and how often the thermostat rests the element decide the bill, and your local rate scales all of it. Use the sensitivity table in the results to see the swing between a heater that idles and one that runs flat out, and enter your own rate from a recent statement rather than a national average. For how that rate is actually built from energy, delivery, and demand charges, our guide to understanding electricity costs breaks down a real bill line by line.

More Electrical calculators

Browse all electrical calculators — Motor FLA, wire sizing, voltage drop, load calculations, and transformer fusing based on NEC standards.

Last updated: July 3, 2026

Written and maintained by Dan Dadovic, Commercial Director at Ezoic Inc. & PhD Candidate in Information Sciences. He works professionally as Commercial Director at Ezoic Inc., leading revenue strategy across digital publishing.

Disclaimer: Calculator results are estimates based on theoretical formulas. Actual performance varies with temperature, battery age, load patterns, and equipment condition. For critical electrical work, consult a licensed electrician.

Editorial review by Doc. dr. sc. Danijel Jerković-Štil, Assistant Professor, FERIT Osijek.