Quick answer
A space heater is a fine tool for one chilly room and a terrible plan for a house. Each unit draws 1,500 watts — most of a 15-amp circuit — delivers the most expensive heat electricity can buy, and heating equipment is tied to tens of thousands of U.S. home fires every year. Central heating costs more upfront but heats every room on purpose-built circuits; a heat pump does it for roughly a third of the electricity.
- A typical portable heater draws 1,500 W ≈ 12.5 amps on high — most of a 15-amp general circuit by itself. Four rooms of them is 6,000 W of pure resistance load spread across circuits never sized for it.
- Resistance heat is the most expensive common heat: at representative local rates (~$0.12/kWh), four heaters running eight hours a day cost roughly $170 a month — for four rooms, not a whole house.
- ESFI attributes more than 65,000 U.S. home fires a year to heating equipment; its rules are strict — plug heaters directly into a wall outlet, never an extension cord or power strip, three feet from anything that burns, never unattended.
- A cold-climate heat pump delivers the same heat for roughly a third of the electricity, in every room, on one properly-sized dedicated circuit.
- The legitimate space-heater role: short-term, supplemental, attended heat for one room — not a heating system.
At a glance
| Portable space heaters | Gas furnace | Cold-climate heat pump | |
|---|---|---|---|
| Coverage | Only rooms with a heater running | Every room via ducts | Every room via ducts or heads |
| Electrical footprint | 1,500 W / 12.5 A per unit on general circuits | Blower on one small circuit; heat from gas | One dedicated, properly-sized circuit |
| Heat economics | 1:1 resistance — the most expensive common heat | Cheaper per BTU at local gas rates | 2–4 units of heat per unit of electricity |
| Safety model | Attended-use appliance with strict placement rules | Permitted, inspected fixed equipment | Permitted, inspected fixed equipment |
| 2026 rebates | None | None | WA HEAR + utility rebates |
What does each option cost installed in the Seattle area?
The sticker prices aren't the story here — the operating math and the circuit reality are. A space heater is cheap until you ask it to be a heating system; then it becomes the most expensive heat in the house, room by room.
| Option | Typical installed range | What that covers |
|---|---|---|
| Portable space heater | $30–$150 retail per unit | A consumer appliance, not installed equipment. Budget its operating cost honestly: one unit on high is ~1.5 kWh every hour it runs. |
| Gas furnace (high-efficiency) | $6,000–$11,000 | Whole-home heat on existing ducts — permit, code items, and haul-away included. |
| Cold-climate heat pump system | $12,000–$20,000 | Whole-home heating and cooling before rebates — the only option on this page Washington incentives support. |
What changes the price
- Operating hours: resistance heat's cost scales linearly — every hour of every heater is full price.
- Circuit reality: older homes with 15-amp general circuits can't run a heater plus much of anything else on the same run.
- What's being avoided: if space heaters are compensating for a dead or dying furnace, the repair-vs-replace math belongs in the decision.
- Rebates: WA HEAR and utility programs can take thousands off a heat-pump install — no program funds space heaters.
Ranges are representative Seattle / Puget Sound installed prices, not a quote — your home's specifics set the real number. Eco gives you an upfront price before any work begins.
How do they work differently?
How a space heater heats
A resistance element converts electricity to heat at exactly 1:1 and a small fan pushes it into the room. Nothing is wrong with the physics — it's the same principle as an electric furnace, shrunk to a plug. The problems are scale and infrastructure: the plug limits it to 1,500 watts, the circuit behind the plug was sized for lamps and laptops, and the heat stops at the doorway of whichever room it's in.
How central heating heats
A furnace or heat pump generates or moves heat at whole-house scale and distributes it through ducts or refrigerant lines sized for the job, on dedicated circuits designed, permitted, and inspected for continuous load. A heat pump adds the multiplier that no plug-in can: instead of making heat at 1:1, it moves heat from outdoor air at 2–4 units delivered per unit of electricity purchased.
Pros and cons, honestly
Portable space heaters
Pros
- Cheap to buy and instantly deployable
- Genuinely useful for one room, short-term, attended
- Zone-of-one heating with zero installation
Cons
- The most expensive common heat per delivered BTU
- 1,500 W claims most of a 15-amp circuit — trips, overheated cords, and overloaded outlets follow
- Heating equipment is tied to tens of thousands of U.S. home fires annually; placement and supervision rules are strict
- No whole-home coverage, no thermostat coordination, no rebate support
Central heating
Pros
- Every room heated, one thermostat, purpose-built circuits
- Permitted and inspected — the safety model is engineering, not vigilance
- Heat pump versions cut the electric bill to roughly a third of resistance
- Heat pumps carry Washington's full 2026 rebate stack
Cons
- Real upfront investment
- Installation is a project, not a purchase
- Sizing and duct condition matter — bad ducts tax any central system
Which one should you choose?
Use space heaters when
One room runs cold and you're in it — the home office over the garage, the basement rec room on movie night. Plug the heater directly into a wall outlet (never an extension cord or power strip), keep three feet of clearance from anything that burns, turn it off when you leave, and treat it as what it is: supplemental heat for an attended room, bought by the hour at premium rates.
Choose central heating when
You're heating a home, not a chair. If space heaters have quietly become the plan — because the furnace died, because two rooms never warmed up, because the bills scared you — that's the signal to price the real fix. A furnace restores whole-home heat; a heat pump does it at a third of the electric cost and brings the rebate stack with it. The one-room problem specifically has a purpose-built answer too: a single-zone ductless head.
Also consider: the single-zone mini-split
If the honest problem is one cold room, the grown-up version of a space heater is a single-zone ductless heat pump: permanent, silent, thermostat-controlled, roughly a third of the operating cost per unit of heat, and it air-conditions the same room in summer. It's the difference between renting heat by the hour and owning it.
The verdict, by situation
Space heaters
A tool, not a system
Right for one attended room, short-term, plugged straight into the wall. Wrong the moment it becomes the household heating strategy.
Central heating
The actual answer
Purpose-built circuits, every room covered, inspected equipment. A heat pump version turns the electric-heat math from punishing to favorable.
Single-zone mini-split
The one-cold-room specialist
Permanent zoned heat (and summer cooling) for the room the space heater was babysitting — at a fraction of the operating cost.
Which Washington homes this fits
Home office or bonus room that runs cold
Short-term: a space heater used by the rules. Long-term: a single-zone ductless head ends the problem permanently.
Older Seattle home limping on space heaters after a furnace failure
This is the emergency the repair-vs-replace framework exists for — space heaters are the most expensive and least safe way to defer that decision.
All-electric rental or condo with baseboard gaps
Resistance-on-resistance is the worst-case bill. A ductless heat pump head is the upgrade that actually changes the math.
Well-heated home that just wants a warm bathroom at 6 AM
Legitimate space-heater territory — attended, wall-plugged, on a timer-free circuit with capacity. No project needed.
Ready to compare for your home?
Get honest numbers for both options side by side — an upfront range, the considerations, and the rebates you qualify for, before any work begins.
Continue exploring
- BookHeating services
- BookDuctless mini-split services
- BookElectrical safety inspections
- CompareGas vs Electric Furnace: Which Should a Puget Sound Home Install?
- CompareSingle-Zone vs Multi-Zone Mini-Split: One Head or the Whole House?
- CompareHeat Pump vs Electric Furnace: The All-Electric Showdown
- GuideRepair or replace? The decision framework
- GuideHome electrical guide — what your circuits can carry
- GuideHeat pump vs baseboard heat
- CompareAll heating & air comparisons
Common questions
Is it cheaper to run space heaters than the furnace?
Almost never for more than one room. Four heaters running eight hours a day is roughly 48 kWh — about $170 a month at representative local rates — to heat four rooms poorly. A gas furnace heats the whole house for less, and a heat pump delivers the same heat as those heaters for roughly a third of the electricity.
How many space heaters can one circuit handle?
One — and barely. A 1,500-watt heater draws about 12.5 amps, which is most of a 15-amp circuit's capacity by itself. Two heaters on one circuit, or one heater sharing with a TV and lamps, is a tripped breaker at best. And never run one through an extension cord or power strip; that's how cords overheat.
Are space heaters actually dangerous?
Used outside the rules, yes — heating equipment is tied to tens of thousands of U.S. home fires every year. Used inside the rules (listed unit, wall outlet only, three feet from anything combustible, never unattended, never while sleeping), a modern heater with tip-over and overheat protection is a reasonable short-term tool.
What's the right permanent fix for one cold room?
Usually a single-zone ductless mini-split: permanent, quiet, thermostat-controlled heat at heat-pump efficiency, plus summer cooling. If the whole house runs cold, that's a duct, sizing, or equipment problem worth diagnosing — cold rooms are a symptom we can trace.
Last updated: 2026-07-17
Sources & references
Equipment ratings, program details, and industry figures on this page come from manufacturers and primary sources, linked below. Verify program status and requirements for your home where applicable.
Safety
- Heating equipment is tied to 65,000+ U.S. home fires annually; heaters belong in wall outlets, never extension cords or power strips, with 3 feet of clearance — ESFI — Space Heater Safety
- Home heating fire safety guidance for portable and fixed equipment — NFPA — Heating safety
Equipment & rebates
- Cold-climate heat pumps deliver multiple units of heat per unit of electricity — NEEP — Cold-Climate ASHP List
- WA HEAR rebates fund heat pump installations for income-eligible households — WA Commerce — HEAR program