Converting a Generator to Propane or Natural Gas

If you already own a generator and want the fuel flexibility you did not buy, a conversion kit is worth knowing about. It costs a fraction of replacing the machine, and on a dual fuel generator it can add natural gas — which is the single most useful fuel in a long outage.

How a kit works

Gaseous fuel is delivered to the engine at low pressure through a regulator, and the kit's job is to get it into the intake in a controlled way. The better kits do it without cutting anything: the Westinghouse WGen9500DF kit's listing states that it uses the existing port in the carburetor for the natural gas inlet, requires no permanent modification, retains the ability to run gasoline, and that switching back to propane is simply a matter of reconnecting the stock propane hose.

That reversibility matters more than it sounds. It means the conversion does not strand you on one fuel, does not void your ability to run gasoline when gas is what you have, and does not wreck resale value.

The derating, and why we cannot tell you what it is

This is the honest reason a factory tri-fuel machine is better if you are buying new: you get published numbers you can size from. A conversion is the right answer when you already own the generator.

Which half you can do, and which you cannot

For propane, the whole thing is within reach: fit the kit, attach a tank through a proper regulator hose, done. A two-stage regulator is the part worth spending on, because it holds output pressure steady as the tank empties — a single-stage regulator lets pressure fall and the generator can surge or stall at low tank level.

For natural gas, the generator side is the easy half. The house side — a quick-connect fitting on your gas supply, correctly sized for the flow the generator needs — is licensed gas work in essentially every jurisdiction, is usually permitted and inspected, and must be arranged in advance rather than in the week before a storm.

Before you buy a kit: three checks

1. 1Your exact model. These kits are model-specific — the one here fits the Westinghouse WGEN9500DF and nothing else. Read the label on the frame or control panel.
2. 2Warranty. Check whether fitting a third-party kit affects your generator's warranty. A reversible, no-modification kit is the best case, but the manufacturer's position is worth knowing.
3. 3Your gas supply's capacity, for natural gas. A generator is a significant appliance and the line has to deliver enough flow at enough pressure. This is a question for whoever does the gas work, and it is better asked before you buy the kit than after.

The short answer

The kit, and the hose you need either way

#	Product	Best for	Score	Price
1	Generic (unbranded) Natural Gas Conversion Kit — WGen9500DF A cheap, reversible way to put a WGen9500DF on your gas line — with the house-side connection being licensed work and the output derating unpublished.	Adding natural gas to a dual fuel unit	7.8/10★★★★★	$129.99
2	GasSaf 10 ft Two-Stage Propane Regulator + Hose The right propane hose for a dual fuel generator: two-stage regulation and 10 feet of distance, with the pressure spec published so you can verify fit.	Running a dual fuel generator on a tank	9.0/10★★★★★	$47.99

#ad Prices as of October 5, 2026; they may have changed since. Scores are our editorial judgment from published specifications, not test results — how we pick. How we are funded.

When to buy a new machine instead

If your generator is gasoline-only and old, the arithmetic often favors replacement: a modern dual fuel machine adds propane, a CO shutdown, better outlets and a warranty, and current prices in this class are not far above what a serious conversion plus hoses costs.

If your generator is a recent dual fuel machine and you have a gas line, the conversion is clearly the better buy — you are adding the one fuel that removes refueling from your plan, for a fraction of the cost of a factory tri-fuel machine.

Or buy a factory tri-fuel machine

Tri-fuel with both hoses in the box

Champion 12,500W Tri-Fuel Home Backup

$1,259.99·View on Amazon

Larger homes with real 240V loads

Westinghouse WGen11500TFc 14,500W Tri-Fuel

$1,499.00·View on Amazon

The advantage over a conversion is published per-fuel running watts you can size from. Champion's includes both hoses in the box.