The Best Natural Gas Generators
The best natural gas generators compared — whole-house standby units that run indefinitely off your utility line, plus the tri-fuel portables that can burn natural gas, with wattage derate, hookup requirements and running cost.
A natural gas generator is the one setup that never needs refueling. It draws from the same utility line that feeds your furnace, which means it runs for as long as the outage lasts — days, if it comes to that — with nothing to store, carry or top up. That is why the standard US whole-house backup is a natural gas standby generator on an automatic transfer switch: it starts itself while you are away and shuts down when the power returns. The cost is watts, a professional gas hookup, and a fixed installation spot.
| Model | Best for | Output on natural gas | Notes |
|---|---|---|---|
| Generac Guardian 22 kW | Best overall whole-house | 22 kW on natural gas | The default US choice — widest dealer network, transfer switch included, covers a typical home with central air. |
| Kohler 20RCA (20 kW) | Best premium build | 20 kW on natural gas | Corrosion-resistant enclosure; the pick for coastal and humid climates. |
| Briggs & Stratton PowerProtect+ 26 kW | Best warranty | 26 kW on natural gas | 7-year parts, labor and travel as standard — the longest in the category. |
| Cummins QuietConnect 20 kW | Best quiet standby | 20 kW on natural gas | Industrial engine heritage, tuned for low running noise in a residential setting. |
| DuroMax XP13000HXT (tri-fuel) | Best portable on natural gas | ≈8,500 running on natural gas | Tri-fuel portable that connects to a house gas line — no permanent install. |
The wattage derate — read the natural gas number
Natural gas carries less energy per unit burned than gasoline, so the same engine makes fewer watts on it. Manufacturers quote the gasoline figure first because it is the largest, which catches out buyers sizing a tri-fuel portable for a gas-line hookup. Standby units are rated on natural gas from the start, so the number on the box is the one you get.
| Fuel | Typical output | What you trade |
|---|---|---|
| Gasoline | 100% (the headline rating) | Highest output; the fuel goes stale in storage |
| Propane | ≈90% | Stores for years; needs a tank |
| Natural gas | ≈70–80% | Unlimited runtime from the utility line; lowest cost per hour |
How to choose a natural gas generator
- Size the load, then pick the kW. A 22–26 kW unit covers a typical home including central air; 10–14 kW covers essentials plus one AC for considerably less installed. Work out your actual number with the sizing calculator and check it against the size chart.
- Confirm the gas line can feed it. A 22 kW standby needs meaningful gas flow. Your installer checks the meter capacity and pipe size — an undersized line is the most common surprise in a standby quote, and upgrading it costs real money.
- Budget the whole job. The unit is roughly half the bill. Pad, automatic transfer switch, electrical and gas runs, permit and inspection add about $3,000–$5,000, so an installed unit typically lands at $7,000–$12,000. Price yours with the cost estimator.
- Compare three dealer quotes. Installed price varies more by site access and gas run than by brand badge, so an itemized quote tells you more than a model comparison.
Where natural gas fits against the alternatives
With a gas line at the property, natural gas is the cheapest fuel per hour and the only one that removes refueling entirely. Without one, propane gives you the same long storage life and works with a portable. Want the choice at the machine rather than at purchase? A tri-fuel generator runs on all three. For the broader standby shortlist, see the best whole house generators, and for the brand head-to-head, Generac vs Kohler.
Outputs, prices and specs are planning estimates that change by model — confirm current details with a dealer. A natural gas standby generator must be sized, permitted and installed by licensed electrical and gas professionals to code; the gas hookup is not DIY work. Portable generators must run outdoors only, well clear of doors, windows and vents, because the exhaust contains carbon monoxide.
Frequently asked questions
What are the downsides of using a natural gas generator?
You give up watts and mobility. Natural gas carries less energy per unit than gasoline, so the same engine typically produces around 20–30% fewer watts on natural gas — a generator rated 12,000 W on gas may deliver closer to 9,000 W. The hookup also has to be plumbed to your gas line by a licensed professional, which means a permit and a fixed installation location. And if the outage is caused by an event that also disrupts gas service, your fuel goes with it — rare, but it is the reason many owners choose a tri-fuel unit.
Can a natural gas generator power a house?
Yes — this is the standard whole-house backup setup in the US. A 22–26 kW natural gas standby generator connected through an automatic transfer switch runs a typical home including central air, and because it draws from the utility line it has effectively unlimited runtime: no tanks, no refills, no fuel to store. Size it to your actual load first; a smaller 10–14 kW unit covers essentials plus one AC in many homes at a considerably lower installed price.
Do they make a portable generator that runs on natural gas?
Yes, though almost always as tri-fuel models rather than natural-gas-only. Tri-fuel portables from DuroMax, Firman, Champion and Predator run on gasoline, propane or natural gas, and connect to a house gas line through a quick-connect fitting an installer fits for you. Expect the lowest wattage of the three fuels when running on natural gas, and note that the hose length limits how far from the house you can place the unit — while still keeping the distance the exhaust requires.
Is a natural gas generator worth it?
If you already have a natural gas line and lose power more than once or twice a year, it is usually the best-value whole-house option: the fuel is the cheapest per hour of the three, it never needs storing or refilling, and the generator starts itself while you are away. The case weakens if you have no gas service, if outages are rare, or if your budget will not stretch to the $7,000–$12,000 installed price — in which case a dual-fuel portable through a transfer switch covers essentials for a fraction of that.