Runtime by power station size: Gas furnace blower fan
| Power station size | Typical runtime | Realistic range |
|---|---|---|
| 300 Wh | 51 min | 0.5–1.7 h |
| 500 Wh | 1 h 25 min | 0.8–2.8 h |
| 1,000 Wh | 2 h 50 min | 1.7–5.7 h |
| 1,500 Wh | 4 h 15 min | 2.5–8.5 h |
| 2,000 Wh | 5 h 40 min | 3.4–11.3 h |
| 3,000 Wh | 8 h 30 min | 5.1–17.0 h |
Why a gas furnace stops in a power cut
Without electricity, a modern gas furnace can't ignite, run its safety controls or blow warm air through the ducts. The good news is that it needs far less power than electric heat: the gas does the heating, the electricity only moves air. Running it on a power station is one of the most efficient ways to heat a whole house in an outage.
- Older blowers (PSC motors) often draw 400–800 W.
- Newer variable-speed (ECM) blowers can draw much less at low speed, sometimes under 200 W.
- The furnace cycles with the thermostat, so its average over an hour depends on how cold it is outside and how warm you keep the house.
Measure your own furnace if you can: an electrician can clamp a meter on its supply, or you can read the blower motor's amps on its label and multiply by 120.
How to connect it safely
Most furnaces are wired straight into a circuit with a service switch, not plugged in. The safe options, installed by a licensed electrician, are:
- a furnace transfer switch with an inlet you plug the station into, or
- a manual transfer switch or inlet for a few essential circuits, including the furnace.
Never backfeed your house by plugging a station into a wall outlet with a double-ended cord. It can electrocute utility workers and start fires.
If the furnace won't light on the power station
Furnace flame sensors need correct polarity and, in many cases, a neutral connected to ground. Some power stations have a "floating" neutral, and a furnace on one may try to ignite, then shut down. If that happens, ask an HVAC technician or electrician to check the connection. Don't bypass any furnace safety control.
Stretch the battery
- Lower the thermostat a few degrees: fewer cycles means proportionally more hours.
- Close off rooms you aren't using and keep curtains closed at night.
- Add solar or a car charger for long outages, and keep the station indoors, since batteries lose capacity in the cold. An electric blanket at night uses far less.