Generators

Is a Dual Fuel Generator Worth It?

Usually yes, and for one reason that has nothing to do with running cost. But there is a defensible case for gasoline plus a bottle of stabilizer.

Written byMike M.

PublishedOctober 5, 2026

Disclosure: we earn a commission on purchases made through links on this page, at no cost to you. It does not affect what we recommend or what we say about it — how we are funded.

The short answer

Yes, in most cases, but not for the reason usually given. Dual fuel is not cheaper to run — propane carries fewer BTU per gallon than gasoline, so you burn more volume for the same work. It is worth it because propane stores indefinitely while gasoline degrades within months, and stale fuel is the most common reason a stored generator will not start. The cost is roughly 10% of the output.

The argument that is usually made, and why it is weak

People say dual fuel is "cheaper to run on propane". Generally it is not. Propane has fewer BTU per gallon than gasoline, so a generator consumes more volume of propane to produce the same watts. Unless your local propane price is unusually low relative to gasoline, running cost is not the argument.

The argument that actually holds

Gasoline goes bad and propane does not. Modern pump gasoline contains ethanol, which draws moisture from the air; the fuel oxidizes and leaves gums and varnish in the tiny passages of a carburetor. STA-BIL states its storage stabilizer keeps gasoline fresh for up to 24 months — which is an admission that untreated gasoline does not last anywhere near that long.

A backup generator spends 99% of its life not running. That makes fuel storage its dominant real-world failure mode, and propane simply does not have the problem. A tank in the garage is as good in five years as the day you bought it.

What dual fuel costs and buys

Output penalty on propane: ~10% (published, consistently)
Volume burned: More, per unit of work
Storage life: Indefinite vs months
Refueling: Tank swap vs pouring near a hot engine
Price premium: Usually modest

The 10% penalty is consistent across Westinghouse, Champion and WEN's published figures. The storage line is the one that decides it.

The secondary benefits people underrate

Refueling is safer. Swapping a propane tank involves no liquid fuel near a hot engine in the dark. Pouring gasoline does, and that is the single most hazardous routine moment in generator ownership.
Cleaner combustion. Propane generally runs cleaner, with less carbon deposit and less oil contamination over time.
Availability in an outage. Propane exchange cages are often restocked when gas station pumps still have no power, because they do not need electricity to work.
No ethanol damage. Ethanol is corrosive to some small-engine fuel system components. Running on propane avoids it entirely.

The honest case against

There is one, and it is defensible. If you will genuinely run the generator regularly, gasoline plus stabilizer is fine. Fuel that is used and replaced every few months never has the chance to degrade. A contractor using a generator weekly has no storage problem, and paying for dual fuel capability they will never use is waste.

Two smaller points on the same side: gasoline gives roughly 10% more output from the same machine, and gasoline-only machines are mechanically slightly simpler, with one fewer fuel system to go wrong.

If you go that route, buy stabilizer at the same time as the generator and actually use it. The failure mode you are accepting is a specific and well-documented one.

The short answer

Three dual fuel picks, and two good gasoline-only machines

#	Product	Best for	Score	Price
1	WEN DF8000X 8,000W Dual Fuel The best-value correctly-sized home backup generator here: enough for every essential circuit, dual fuel, CO shutoff, a real transfer-switch outlet, and no money spent on capacity you will not use.	Essential circuits, dual fuel, lowest cost	8.5/10	$623.17
2	Westinghouse WGen9500DF 12,500W Dual Fuel The most broadly sensible home backup generator on the market: enough running watts for a whole essential-circuit panel, both transfer-switch outlets, and dual fuel — with the caveat that it has no CO shutoff.	The default whole-house pick	8.8/10	$999.00
3	Champion 11,500W Dual Fuel Electric Start The most honestly specified generator in its class, with CO shutoff and the best after-sale support in the category.	Published propane numbers you can plan on	8.7/10	$989.99
4	Generac 8,125W Starting Portable The right size for most people who think they need 10,000 watts: enough running capacity for every essential circuit, with surge headroom for motor startup.	Essential circuits on a budget	7.8/10	$899.00
5	DeWalt DXGNR8000 10,000W Starting Worth the premium if you want to see your load rather than guess at it — the metering genuinely prevents the overload that kills generators.	Live load and runtime metering	7.7/10	$1,199.00

#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.

Buy one of these either way

Running a dual fuel generator on a tank

GasSaf 10 ft Two-Stage Propane Regulator + Hose

$47.99View on Amazon

Keeping stored gasoline usable

STA-BIL Storage Fuel Stabilizer, 32 oz

$13.58View on Amazon

A two-stage propane regulator if you go dual fuel; stabilizer if you go gasoline-only. Either one is the accessory that makes the fuel decision actually work.

And the option that beats both

If your house has a natural gas line, tri-fuel makes this entire discussion moot. A plumbed supply does not run out, does not degrade, and needs no storage at all. The costs are a 15-25% output derating and a licensed gas connection — and for anyone expecting multi-day outages, it is the best money on this site.

Questions people actually ask

Is a dual fuel generator worth the extra money?

In most cases yes, because propane stores indefinitely while gasoline degrades within months, and stale fuel is the most common reason a stored generator will not start. The cost is roughly 10% of the output and usually a modest price premium.

Is propane cheaper than gasoline for a generator?

Generally not per unit of energy. Propane carries fewer BTU per gallon, so a generator burns more volume to do the same work. The advantage is storage life and refueling safety, not running cost.

How much output do you lose on propane?

About 10%, consistently where manufacturers publish it. Westinghouse's WGen9500DF goes from 9,500 running watts on gasoline to 8,500 on propane; Champion's 11,500 W from 9,200 to 8,280; WEN's DF8000X from 6,500 to 5,850.

When is a gasoline-only generator the better choice?

When you will genuinely use it regularly, so the fuel is rotated and never has the chance to degrade. A contractor using a generator weekly has no storage problem, gets about 10% more output, and has one fewer fuel system to maintain.

Can I convert my gasoline generator to propane?

Model-specific conversion kits exist for many popular machines, use the carburetor's existing port and are reversible with no permanent modification. The main drawback is that the output derating is often not published for the kit.

Is natural gas better than propane for a generator?

For runtime, decisively — a plumbed line does not run out and needs no storage. The costs are a larger output derating of 15-25% and a licensed gas connection on the house side, which has to be arranged in advance.