An electric blanket is mostly a resistive heating element under fabric. W is highest when the control calls for heat; many models thermostat-cycle, so overnight average W is often below the brief on-time peak you see on a kill-a-watt.
How to calculate kWh from watts and hours and Daily off-grid use in Wh turn hours into energy rows. Generator running watts vs starting watts is not a well-pump-class LRA story, but you still must not stack a warm blanket on the same cheap strip as a space heater or hair dryer. Add router and laptop in the same outage list. Inverter sizing for off-grid solar and Pure sine vs modified sine matter if the same AC branch feeds sensitive gear. Use the WattSizing calculator.
1) Running W when heating (ballpark; label wins)
| Blanket class | On-time W (typical) | What moves it |
|---|---|---|
| Throw / small | ~50–100 | Shorter run, one zone |
| Twin | ~60–120 | Setpoint dial |
| Full / double | ~80–150 | More element area |
| Queen | ~100–180 | Same |
| King / dual (both sides hot) | ~120–250 | Both sides high can add more than a single zone |
Pre-heat 15–30 minutes then dial down often cuts kWh versus max all night.
2) Why the meter bounces: thermostatic cycling
On W and duty cycle set the average W for the hour. That average is what turns into kWh with kWh from watts and hours—not the sticker “high” number alone.
3) kWh: one night (sketch)
Example: 70 W average × 8 h = 0.56 kWh—kWh from watts and hours. U.S. retail $/kWh is on your bill; EIA electricity explained is a neutral anchor.
4) 15 A branches, strips, and what not to stack
A ~150 W blanket is small next to central air or a portable AC—but a bad strip with a space heater, kettle, or toaster in the same moment is still how nuisance trips happen. Running vs starting is the frame for a portable gen that also feeds a fridge in winter outage math.
5) Off-grid: often a kind resistive row
Peak W in the low hundreds is easier on a small inverter than a clothes dryer or tank water heater class loads. The story is still kWh: long on-times on a cold night add Wh you have to carry in daily Wh planning. If the same AC branch backs a router, laptop, or other fussy switch-mode gear, read pure sine vs modified sine beside the blanket row.
6) Safety (read the manual)
Follow the label: no pinched cords, no sleeping on the control box, and replace any blanket with cut fabric, scorch marks, or a cord that runs hot. Do not hide the cord under rugs or clamp it in bed frames. Do not load a cheap strip with the blanket plus another high-W space heater or hair dryer on the same branch.
FAQs
How many watts does an electric blanket use on high?
On-time W is often ~50–250 depending on size and dual controls; the nameplate or packaging is the first place to check before a meter log.
Do electric blankets have a well-pump-style surge?
No meaningful LRA row like a well pump—heat is resistive. Generator running vs starting is about what else shares the cord and gen at the same instant.
Electric blanket vs space heater watts?
A blanket warms you in the ~tens–low hundreds of W when on; many space heaters sit ~750–1500 W continuous—kWh and 15 A stacking are not the same math.
How much kWh overnight?
Use average W × hours with kWh from watts and hours; a cycling ~70 W average × 8 h is ~0.56 kWh—your dial and room temp move that a lot.
Both sides of a dual control on high?
Yes—king-size dual zones can land higher peak W than a single zone throw; log concurrent W for backup if both sleepers run aggressive setpoints.
Can I run an electric blanket on a portable generator?
Often yes at the W rows here; the caution is still shared circuits and total running W with fridge and kitchen peaks in a winter outage list.
Is a modified-sine inverter OK for a blanket?
Many resistive blankets tolerate it; if the same inverter also runs noisy audio or fussy chargers, lean pure for the whole branch decision, not the blanket alone.
Recap: Ballpark on-time W ~50–250 by size and dial; overnight kWh follows cycling average W × hours; 15 A stacks and off-grid inverter rows need concurrent W and clean AC if mixed loads matter. Tighten the row in the WattSizing calculator.
