Can a power station run a gas furnace?
Short answer
Yes, most power stations of 1,000 Wh or more can run a gas furnace. The electric part of a gas furnace (the blower, inducer fan and controls) draws roughly 300 to 800 W while running. A 1,000 Wh unit keeps a typical furnace going for about 2 to 6 hours in cold weather, and a 3,600 Wh unit for about 7 to 20 hours. The catch is the connection: most furnaces are hardwired, so you need an electrician-installed inlet or transfer switch.
What a gas furnace actually needs
A gas furnace burns gas for heat, but it cannot run without electricity. Three parts need power: the blower that pushes warm air through the ducts, the small inducer fan that vents exhaust, and the control board with its igniter.
The blower is by far the biggest load. Older furnaces use a single-speed PSC motor that draws around 700 to 900 W. Most furnaces sold in the last decade or so use a variable-speed ECM motor, which usually draws far less, especially at the lower speeds it runs most of the time. The igniter adds a few hundred watts for under a minute at the start of each heating cycle.
Runtime by power station size
The furnace cycles on and off with the thermostat. The columns show average draw over time: a modern variable-speed (ECM) blower in moderate cold, the same blower in hard cold, and an older single-speed (PSC) blower. Figures assume 85% usable battery energy.
| Power station | Older PSC blower (450 W avg) | ECM, hard cold (300 W avg) | ECM, moderate cold (150 W avg) | Starts an older furnace? |
|---|---|---|---|---|
| 256 Wh 300 W output | 29 minutes | 44 minutes | 1.5 hours | No, output too low |
| 512 Wh 600 W output | 58 minutes | 1.5 hours | 2.9 hours | No, output too low |
| 1,024 Wh 1,800 W output | 1.9 hours | 2.9 hours | 5.8 hours | Yes |
| 2,048 Wh 2,400 W output | 3.9 hours | 5.8 hours | 11.6 hours | Yes |
| 3,600 Wh 3,600 W output | 6.8 hours | 10.2 hours | 20.4 hours | Yes |
For your exact appliance and power station, use the runtime calculator.
How to connect a furnace safely
Most furnaces are wired directly into the home's electrical system, with no plug. There are two common, code-compliant ways to power one from a power station or generator, and both are jobs for a licensed electrician:
- A furnace transfer switch or inlet. A dedicated switch next to the furnace lets you choose between utility power and a plug-in source. It is usually the cheapest option.
- A home transfer switch or interlock. This feeds several circuits at once, including the furnace, from a larger power source.
Never backfeed a furnace or any circuit through a wall outlet with a double-ended cord. It can electrocute you or utility workers and damage equipment.
Why some furnaces refuse to run on backup power
Furnace control boards check that the flame has lit using a small electrical signal. On some backup power sources, the way the neutral wire is handled confuses that check, and the furnace shuts down after a few seconds. Pure sine wave output helps, but it does not always solve this. Test your setup on a mild day, well before you need it, and ask the electrician who installs the switch to confirm compatibility.
Make the battery last longer
- Lower the thermostat a few degrees. The blower runs less, and the difference in runtime is significant.
- Close doors and vents to rooms you are not using.
- If your thermostat allows it, avoid running the fan continuously. Set it to auto.
Frequently asked questions
How many watts does a gas furnace use?
The electrical parts of a gas furnace usually draw about 300 to 800 W while running. Older single-speed blowers are at the high end; modern variable-speed blowers often use much less.
Can I plug my furnace into a power station?
Only if it has been fitted with a plug or an inlet by an electrician. Most furnaces are hardwired, so they need a transfer switch or a furnace inlet before they can be powered from a portable source.
Will a power station run a furnace overnight?
A 2,000 Wh unit can run a modern furnace for roughly 6 to 12 hours depending on how cold it is. For a full night in hard cold with an older furnace, you need a larger unit, a generator, or solar recharging.
Sources and method
Runtime figures assume 85% of battery capacity reaches AC appliances and typical US appliance ratings. See exactly how we calculate. Found a mistake? Tell us and we will fix it.