Through a 6-circuit transfer switch it carries the furnace, fridge, well pump, and lights simultaneously — the standard winter-outage setup for cold-climate homes.
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~$849 typical price
Buy on AmazonUse-case guide · 2026
Best generator for a Furnace
A winter outage is a race against your home's falling temperature, and the frustrating part is that a gas furnace needs barely any electricity — a few hundred watts for the blower and controls. The challenge isn't wattage; it's that furnaces are hardwired, so you need the right connection method, not a bigger generator.
The power requirements
Running watts
400–800W (blower motor + controls, gas furnace)
Starting surge
1,200–2,400W (blower start)
- ▸These figures are for gas/propane/oil furnaces. Electric furnaces and heat pumps draw 10,000W+ — that's standby-generator territory.
- ▸Because furnaces are hardwired, a transfer switch (or an electrician-installed furnace plug kit) is required to connect one legally.
Adding more appliances? Run your full load through the sizing calculator →
Our picks
2. Westinghouse iGen4500
9.1
/ 10
If your electrician installs a furnace outlet kit, this runs the blower at library volume all night on eco mode — a much more livable overnight companion than an open-frame machine.
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~$949 typical price
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For homes where frozen pipes are a real risk during away-from-home outages, an automatic standby keeps heat on whether or not anyone's there to pull a starter cord.
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~$5,399 typical price
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- ▸Dual-fuel machines earn their keep in winter: propane doesn't gum carburetors during summer storage, and cold-weather starting on propane is reliable.
- ▸Frozen pipes are the real cost of a heatless outage — a burst pipe claim makes any generator look cheap.
- ▸Run a space heater in one closed room off the same generator to concentrate warmth efficiently.
Frequently asked questions
Can I just plug my furnace into a generator?
Not directly — furnaces are hardwired. You need either a transfer switch covering the furnace circuit or an electrician-installed furnace plug kit. Both are routine, inexpensive electrical jobs.
What size generator runs a gas furnace?
Almost any 2,200W+ generator handles a gas furnace's 400–800 running watts and ~2,000W blower surge. Size up only for the other loads you want alongside heat.