Watts

Typical figures for this type, from the sources at the foot of this page. Watts vary by model and age. Check the label on your own appliance and enter it for an exact answer.

Running, typical
550 W
Running, low to high
300 W to 875 W
Starting
1,200 W800 W to 3,175 W, 2.2 times running
Typical use a day
12 hhours the motor actually runs
Average draw while on
550 W
Voltage
120 V
  • Assumes the motor runs the whole time; real use is often less.

The math

Worked with the typical figure, as the calculator does it.

  1. Output550 W running, so the station's continuous output must be at least 550 W.
  2. Surge1,200 W to start, so its surge rating must be at least 1,200 W.
  3. Average draw550 W: the running watts count for every hour it is on, as if the motor never paused.
  4. A typical day550 W × 12 h = 6,600 Wh a day.
  5. 8 hours of running550 W × 8 h = 4,400 Wh usable, ÷ 0.85 = 5,176 Wh of rated capacity.
  6. 24 hours of running550 W × 24 h = 13,200 Wh usable, ÷ 0.85 = 15,529 Wh of rated capacity.
  7. On the EcoFlow RIVER 3 Plus286 Wh × 0.85 = 243 Wh usable, ÷ 550 W = 27 min.

Stations that run it

Every power station in the data with this appliance alone plugged in, at 85% efficiency. Type the running watts from your own label and the table works it out again.

Add it to the runtime calculator with the rest of your list

What moves the number

Gas does the heating, but the blower that moves the warm air needs power. A 1/2 HP blower runs at 300 W to 875 W, and its start can reach 3,175 W. Blowers with variable speed motors use less on their lower speeds.

The 12 hours a day here is our planning default for a winter outage, with the blower running the whole time.

Questions

How many watts does a gas furnace blower fan (1/2 HP) use?
About 550 W while running, from 300 W to 875 W across the models in our sources. It needs about 1,200 W for a moment at start. Watts vary by model and age. Check the label on your own appliance and enter it for an exact answer.
Can a portable power station run a gas furnace blower fan (1/2 HP)?
Yes. 44 of the 54 power stations in the Enough Watts data set can power it on its own. It takes at least 550 W of continuous output and a surge rating of 1,200 W.
How long will a power station run a gas furnace blower fan (1/2 HP)?
It depends on the battery. At 85% efficiency the smallest station that powers it, the EcoFlow RIVER 3 Plus (286 Wh), gives about 27 min. The largest, the EcoFlow DELTA Pro Ultra X (12,288 Wh), gives about 19.0 h.
Why does a gas furnace blower fan (1/2 HP) need a high surge rating?
Its motor draws about 1,200 W for a moment at start, 2.2 times its 550 W running figure. A station whose surge rating is below that cannot start it, even when the continuous output is enough. 44 of the 54 stations pass that check.

Sources

Researched from these pages, then checked against them a second time. The check corrected at least one figure.

  1. Generator Wattage Chart: Common Appliances & Tools - Champion Power Equipment generator maker guide, checked
  2. Generac GP Series 3600-8000 Watt Portable Generators brochure (How much power do you need? table) generator maker guide, checked

We read published figures and do the math; we do not measure appliances. The methodology states every formula on this page. Capacities are rated watt hours: 1,000 Wh rated gives 850 Wh usable at the default.