Space Heater vs Electric Blanket Guide: Cost & Comfort

The short version

Run your own numbers in the Space Heater vs Electric Blanket: Yearly Cost Calculator. At the defaults — a 1,500-watt heater running 4 hours a day for 120 days, a 100-watt blanket running 8 hours a night for 120 nights, and $0.17 per kWh — the heater uses 720.00 kWh and costs $122.40 a year, and the blanket uses 96.00 kWh and costs $16.32, so the blanket saves $106.08 a year. The blanket wins on cost by a wide margin — but it only warms the bed, not the room, and that limit decides the whole question.

The cost math, in plain words

Energy is watts times time. The heater draws 1,500 watts for 4 hours a day, 120 days a year: 1,500 × 4 × 120 ÷ 1,000 is 720.00 kilowatt-hours a year, which at $0.17 per kilowatt-hour is $122.40 a year. The blanket draws 100 watts for 8 hours a night, 120 nights a year: 100 × 8 × 120 ÷ 1,000 is 96.00 kilowatt-hours, or $16.32 a year. The gap is $106.08. The blanket runs twice as long each night but draws a fifteenth of the watts. Per night the heater costs $1.02 and the blanket $0.136; per hour, $0.255 against $0.017.

Why the blanket is so cheap: watts × hours

The blanket's advantage is not efficiency — both appliances turn nearly all their electricity into heat. The advantage is the size of the job. A space heater warms a whole roomful of air, and air is a terrible thing to heat: it leaks out and rises to the ceiling, and needs constant topping up. A blanket warms a few kilograms of person and bedding, and the bedding traps the heat against the body. That is why the watts differ by a factor of fifteen while the hours differ by a factor of two in the blanket's favour — and why the blanket uses 96 kWh a year against the heater's 720.

Every branch, checked

Eight hours a day for the heater is $244.80 against $16.32, a saving of $228.48; a short 60-day season is $61.20 against $8.16, a saving of $53.04; a $0.30 rate is $216.00 against $28.80, a saving of $187.20; and a 750-watt heater on low is $61.20 against $16.32, a saving of $44.88. In none of these branches does the winner flip — the blanket wins them all, and the gap grows with every hour the heater runs and every cent the rate rises.

Comfort vs cost: the room, not the bed

The blanket only warms the bed, not the room — and that is the whole decision. If the room itself must stay warm, the heater is the only option and the cost comparison breaks. A baby needs warm air, not just warm sheets; pipes in an outside wall can freeze; and someone working from home needs the room warm. In those cases the $106.08 is not a saving you can collect; it is the price of keeping the room liveable, and the heater's $122.40 a year is simply what that costs. The blanket is the right tool when the only thing that needs to be warm is the person in the bed: it pre-warms the sheets, holds a steady low heat all night, and lets the room sit a few degrees cooler. The cheapest option of all is both: run the heater for an hour to take the chill off the room, then sleep under the blanket with the heater off.

Safety first

Cost is the wrong reason to run a heater unsafely. Never leave a space heater unattended, and never run one while you sleep. Keep it at least three feet from bedding, curtains, and furniture, plug it straight into a wall outlet and never into an extension cord or power strip, and use one with tip-over and overheat shut-off. An electric blanket is the safer overnight option, but it has rules of its own: never fold or bunch it while it is on, replace it if the wires feel uneven or the fabric is scorched, and use the auto-off timer so it switches itself off once you are warm. These are general safety notes, not a substitute for the manufacturer's instructions.

The honest flip: blanket on high, heater on brief

There is one realistic way the heater wins on cost, and it is about how hard each one is pushed. Put the blanket on high — 200 watts — for 10 hours a night, and it uses 200 × 10 × 120 ÷ 1,000, or 240.00 kWh a year, which is $40.80 a year. Use the heater only to pre-warm the room for 1 hour a night, and it uses 1,500 × 1 × 120 ÷ 1,000, or 180.00 kWh a year, which is $30.60 a year. The heater saves $10.20 a year. 200 watts for 10 hours is more energy than 1,500 watts for 1 hour — hours matter as much as watts. A blanket on its lowest setting, or switched off once you are warm, stays at $16.32 a year; a blanket cranked to high and left on all night costs two and a half times that.

Who should pick which

Pick the blanket if you wake up cold and the room can stay cool: it costs $16.32 a year to run, warms the bed all night, and saves $106.08 against the heater. Pick the heater if the room itself must stay warm — a baby, pipes, or a home office — because the blanket cannot do that job at any price. Pick both if you want the cheapest comfortable night: pre-warm the room for an hour with the heater ($30.60 a year), then sleep under the blanket with the heater off. And never pick a heater to run overnight: no saving is worth sleeping next to an unattended heater.

Verdict

Default to the blanket for sleeping and to the heater for living in the room — and run the heater for an hour, not all night. At typical settings the blanket saves $106.08 a year — $16.32 against $122.40 — and the saving survives every branch: $228.48 at 8 hours a day, $53.04 for a short season, $187.20 at a $0.30 rate, $44.88 for a heater on low. The heater wins only when the blanket is cranked to high all night while the heater runs for a single hour — and only by $10.20 a year. So keep the blanket low, switch it off once you are warm, and let the heater do the brief job of taking the chill off the room.