Space Heaters vs Central Heat: What's Actually Cheaper?

TL;DR: A typical 1,500-watt space heater costs roughly $0.19-$0.24 an hour to run at national average electricity rates, or about $46-$60 a month if used 8 hours a day. Central heat (gas furnace) usually costs less per square foot to heat a whole house, but a space heater can save money if you're only warming one occupied room and keeping the rest of the house at a lower setback temperature. The breakeven depends on how many rooms you'd otherwise heat and your local energy rates, not on which system is "better."

_Last reviewed: July 2026 · 7 min read_

Your thermostat says 68 and your gas bill still climbed $80 last month, so you're eyeing that space heater in the garage and wondering if it'd actually be cheaper to just heat the room you're sitting in. The honest answer is: sometimes yes, sometimes no, and it comes down to arithmetic most people never bother to do.

Okoniq Property Hub helps you log utility bills and seasonal heating costs side by side, so you can see which rooms or systems are actually driving your numbers instead of guessing.

What does a space heater actually cost per hour compared to central heat?

A standard 1,500-watt electric space heater costs about $0.19 to $0.24 per hour to run, using the US average residential electricity rate of roughly $0.16 per kilowatt-hour as of late 2024. Run it 8 hours a day for a month and you're looking at $46 to $58, just for that one unit in that one room.

Central heat is harder to price per hour because it depends on your furnace's fuel type, efficiency rating, and how much square footage it's conditioning. A mid-efficiency gas furnace (80% AFUE) burning natural gas at the national average of about $1.20 per therm costs roughly $0.90 to $1.50 an hour to heat an average 1,800-square-foot home, but that's heating every room, not one. Per square foot, central gas heat is almost always cheaper than electric resistance heat. The catch is that central heat doesn't have an "off" switch for the rooms you're not using. A well-maintained furnace with clean filters matters here too, since a clogged filter forces the system to run longer for the same result. Check your filter using guidance in 1-inch vs 4-inch furnace filters: which lasts longer? if you haven't swapped it this season.

When does a space heater actually save you money?

A space heater saves money when you're heating one occupied room and letting the rest of the house sit at a lower temperature, typically 60-62°F instead of 68-70°F. If you live alone and spend most evenings in one room, dropping your central thermostat 6-8 degrees and running a space heater in that room can save $20-40 a month compared to heating the whole house to your normal comfort level.

The math flips fast once you're heating two or more rooms, or if the rest of the house drops low enough that pipes are at risk of freezing, which then forces you to keep central heat running anyway. It also flips if your home has poor insulation in that one room, since a space heater fighting a drafty window or uninsulated exterior wall burns through electricity without ever reaching a comfortable temperature. If cold air is sneaking in around gaps, look at what's letting the heat escape before blaming the heater itself.

Is it safe to run a space heater on your home's wiring?

Most home circuits handle a single 1,500-watt space heater fine, but older wiring or an overloaded outlet is a real fire risk, and this is where the "cheaper" math can turn expensive fast. Space heaters are one of the leading causes of residential heating fires in the US, according to the National Fire Protection Association, and undersized or outdated wiring is a common factor.

Before you plug one in for the season, check what kind of electrical system you're working with. Homes built before the 1960s sometimes still have wiring that wasn't designed for modern loads, and it's worth reviewing 5 signs you still have knob-and-tube wiring if your house is that old. Two-prong outlets are another warning sign worth checking, covered in 2-prong vs 3-prong outlets: how to upgrade safely. And if you're running a space heater alongside other appliances on the same circuit, it's worth confirming your panel has the capacity, which 100 vs 200 amp service: do you have enough power? walks through in plain terms.

| | Space Heater | Central Heat (Gas Furnace) | |---|---|---| | Cost to heat one room | $0.19-$0.24/hour | Not zone-specific; heats whole house | | Cost to heat whole house | Expensive if multiple units | $0.90-$1.50/hour (avg 1,800 sq ft) | | Best use case | Single occupied room, short periods | Whole-house comfort, cold climates | | Safety consideration | Circuit load, older wiring risk | Furnace maintenance, filter changes |

What's the real breakeven point for zone heating vs central heat?

The breakeven point is usually around one room heated for 6-8 hours a day. Below that, a space heater with a central setback usually wins. Above that, or if you're heating two rooms plus common areas like a bathroom or hallway, central heat almost always costs less overall because gas is cheaper per unit of heat than electricity in most US markets.

To find your actual number, take your last gas bill during a similar cold month, divide by the square footage you're heating, and compare that per-square-foot cost to what a space heater would cost to cover just your occupied space. Most owner-operators find the breakeven shifts seasonally too. In the shoulder months of late fall and early spring, a space heater in one room while the furnace stays off entirely can save $50-100 a month. In the depths of a January cold snap, trying to zone-heat with space heaters usually costs more because the heaters have to run nearly constantly to fight outdoor temperature swings.

FAQ

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

For most homes, central heat is cheaper across an entire winter if you're keeping the whole house comfortable, since gas costs less per unit of heat than electricity. Space heaters win only when you're consistently heating one room and letting the rest of the house drop 6-8 degrees.

How much electricity does a space heater use per month?

A 1,500-watt space heater run 8 hours a day for 30 days uses about 360 kWh, which costs roughly $46-$58 a month at the US average rate of $0.16 per kWh. Usage and cost scale directly with hours run and your local electricity rate.

Can running a space heater damage my electrical system?

Yes, if the circuit is already near capacity or the wiring is old, a space heater can overheat outlets or trip breakers repeatedly. Homes with knob-and-tube wiring or two-prong outlets are at higher risk and should be evaluated before adding a 1,500-watt load.

Do space heaters use more energy than a furnace?

Per hour, a single space heater usually uses less total energy than a central furnace, but it's only heating one room while the furnace heats the whole house. Comparing them fairly means dividing furnace cost by square footage and comparing it to what the space heater covers.

What's the safest wattage for a space heater in an older home?

Most 1,500-watt space heaters are designed for a standard 15 or 20-amp circuit, but in an older home it's worth confirming nothing else major is drawing power on that same circuit at the same time. A licensed electrician can check your panel capacity in under an hour if you're unsure.

This is educational information, not electrical or financial advice. Call a licensed electrician if you're unsure about your home's wiring capacity before running space heaters regularly.