How many watts does a furnace blower use, and how long will a battery run it?
Furnace blowers draw about 400–1,200 W while running and up to 3,500 W for a moment as the motor starts.
It cycles on and off, so a typical one uses about 4,400 watt-hours a day, about 182 W on average. A 1 kWh station runs it about 4.5 hours.
A 2 kWh station runs it about 8.6 hours.
That is the middle of our range for this appliance. Yours may use less or a lot more: the range, the assumptions and every unit we track are below. Hours are hours of use on one full charge, counting the power each station uses just to stay on.
Older single-speed or variable-speed blower?
Most of the answer is the blower motor. An older single-speed motor draws about 500–550 W. A variable-speed motor draws as little as 80 W and about 400 W at its highest setting. The furnace label or manual names the motor type.
| Blower | Running | At start | 1 kWh station | 2 kWh station | 3.8 kWh station |
|---|---|---|---|---|---|
| Older single-speed blower | 500–550 W | pulls 3 to 5 times its running watts for a split second at start; up to 2,750 W | about 4.5 h up to 5 h | about 8.6 h up to 9.3 h | about 15 h up to 16 h |
| Variable-speed blower | 80–400 W | soft-starts at under 2 times its running watts; up to 800 W | about 6.1 h up to 23 h | about 11 h up to 36 h | about 19 h up to 49 h |
Hours at the higher running figure with the blower on about a third of each hour (33%), the top of EcoFlow’s 25–33% for a properly sized furnace in a typical winter. A hard freeze runs it more. The controls and igniter add a little; they are not counted.
Sources: DOE Building America Solution Center (PNNL): ECM air handler fans, read 2026-09-30; EcoFlow: portable power station for a gas furnace (2026-09-22), read 2026-09-30. Which power stations to buy for a furnace.
Hours of use by battery size
| Battery (listed size) | Typical | Hard-working unit | Efficient unit |
|---|---|---|---|
| 500 Wh | about 2.3 h | 0.5 h | 3.5 h |
| 1,000 Wh | about 4.5 h | 1 h | 6.7 h |
| 2,000 Wh | about 8.6 h | 2 h | 12 h |
| 3,000 Wh | about 12 h | 3 h | 17 h |
| 5,000 Wh | about 18 h | 4.9 h | 25 h |
Hours count the power a typical untested station of each size uses just to stay on. Typical uses about 182 W; hard-working 1,200 W on 70% of the time; efficient 400 W on 30% of the time. The station must also start it: see which units can, below.
How much battery a typical one needs
| Outage | Battery needed, typical |
|---|---|
| 12 hours | about 2,800 Wh |
| 24 hours | about 5,600 Wh |
| 3 days | about 16,800 Wh |
Listed watt-hours, counting the inverter loss and the power the station uses to stay on. Past a day, most plans add solar or a generator rather than a bigger battery.
The range behind that
A furnace blower uses about 400–1,200 watts while running , and needs up to 3,500 watts for a split second when it starts. Over 24 hours it uses roughly 2,880–20,160 watt-hours.
Buy for the higher number in each range. 29 of the 82 products we track can run it. For example, the EcoFlow DELTA Pro 3 would run it for 4.2–22 hours of use, from a hard-working unit to an efficient one.
This one is not plug-and-play. It is wired into your house, so you need a licensed electrician.
Sized in a full plan
This load is part of a plan we ran against every unit we track, with picks: The best portable generator for home backup; Can a power station run a gas furnace? Yes, with the right hookup.
The numbers behind that
Cycling depends on outdoor temperature and how well the house holds heat. Cold snaps keep it running more of the time.
What it draws while it is actually on.
The momentary surge when a motor or compressor kicks in. Undersized systems fail here, not on running watts.
How much of the hour it is actually drawing power. This is what turns running watts into energy.
A battery gives back less than its label: about 10% is lost turning it into wall power, and the station uses some just to stay on.
Wired into the building
This is connected to your house wiring, not an outlet. Powering it from a portable source needs a transfer switch or an inlet installed by a licensed electrician. Never run a cord from a generator into an outlet to feed a circuit: backfeeding can kill line workers and start fires.
Safety
A furnace is wired into the building, not plugged in. Powering it from a portable source requires a transfer switch or an inlet installed by a licensed electrician. Never backfeed a furnace circuit.
Check this yourself
Read the label on the blower motor, and note whether it is an older single-speed motor or a variable-speed one. They behave very differently.
What can run it
Hours of use on one full charge: typical, then the range from a hard-working unit to an efficient one. “Starts it” means the peak output covers even a hard-starting one; “may not start a hard-starting one” means it covers the lower end of the starting range only.
| Product | Continuous | Peak | Starts it? | Hours of use |
|---|---|---|---|---|
| Zendure SuperBase V6400 | 3,800W | 5,000W | starts it | about 22h 6.2–29h |
| OUKITEL P5000 Pro | 3,600W | not listed by the maker | maker gives no peak figure | about 19h 5–25h |
| Jackery Explorer 5000 Plus | 7,200W | 14,400W | starts it | about 17h 4.8–22h |
| Zendure SuperBase V4600 | 3,800W | 5,000W | starts it | about 17h 4.5–24h |
| EcoFlow DELTA Pro 3 | 4,000W | 8,000W | starts it | about 16h 4.2–22h |
| FIRMAN WH03242 Dual-Fuel Inverter | 3,200W | 4,000W | starts it | fuel-dependent |
| Champion 201444 5500W Inverter | 4,000W | 5,500W | starts it | fuel-dependent |
| Champion 201255 5500W Open Frame Inverter (CARB) | 4,000W | 5,500W | starts it | fuel-dependent |
What will not work, and why
49 of 82 products cannot run this.
- Anker SOLIX F3000 (UL9540 Certificated) — 2,582Wh usable cannot cover a 24-hour outage for these loads, which need 2,880–20,160Wh. It would carry the plan for roughly 2.2h before recharging.
- EcoFlow DELTA 3 Ultra (3072Wh) — 2,624Wh usable cannot cover a 24-hour outage for these loads, which need 2,880–20,160Wh. It would carry the plan for roughly 2.2h before recharging.
- Jackery HomePower 3000 — 2,582Wh usable cannot cover a 24-hour outage for these loads, which need 2,880–20,160Wh. It would carry the plan for roughly 2.2h before recharging.
- EcoFlow DELTA 3 Ultra Plus (3072Wh) — 2,582Wh usable cannot cover a 24-hour outage for these loads, which need 2,880–20,160Wh. It would carry the plan for roughly 2.2h before recharging.
- PECRON E3600LFP — 2,582Wh usable cannot cover a 24-hour outage for these loads, which need 2,880–20,160Wh. It would carry the plan for roughly 2.2h before recharging.
- PECRON F3000LFP — 2,650Wh usable cannot cover a 24-hour outage for these loads, which need 2,880–20,160Wh. It would carry the plan for roughly 2.2h before recharging.