NATURAL GAS VS PROPANE FOR HOME GENERATORS
Here is a fact that surprises most buyers: nearly every modern home standby generator runs on BOTH natural gas and propane — your installer selects the fuel at startup. So the question is not which generator to buy; it is which fuel your property should feed it. The answer is usually decided for you, but the details are worth knowing.
The 60-second decision
- Have a natural gas line at the house? Use it. Unlimited runtime, no tank to fill, lowest hassle. This is the default for most suburban homes.
- No gas line? Propane is your answer — and it is a perfectly good one. You will add a tank (typically 250-500 gallons for standby duty) and a refill relationship.
Natural gas: the case for
- Unlimited runtime. The utility keeps supplying gas through multi-day outages — no 3 AM refueling, no delivery trucks after a hurricane.
- No tank to buy, rent, bury, or screen from view.
- Generally cheapest per hour of operation in most U.S. markets.
The honest caveats: NG delivers slightly less power than LP in the same engine (most units are rated about 5-10% lower on NG — you will see both numbers on every spec sheet, like "22kW LP / 19.5kW NG"). And in rare catastrophic events, gas service itself can be interrupted — uncommon, but propane owners like owning their fuel.
Propane: the case for
- Energy-dense and stable — propane stores for years without degrading (unlike gasoline).
- Full rated output — that "22kW" is the LP number.
- You own your runtime. A 500-gallon tank typically buys several days of heavy use; calm-season top-offs are cheap insurance. Before storm season, fill it — demand spikes after landfall, not before.
Caveats: tank cost or rental, permitting and placement rules, and the discipline of watching the gauge during long outages (remote tank monitors solve this).
What about diesel?
Residential air-cooled standby units do not come in diesel; diesel enters at larger liquid-cooled sizes, mostly for commercial settings — see the diesel generators category if you have a genuine commercial-scale need. For homes, NG and LP own the market for good reasons: clean burning, quiet, and no fuel that goes stale.
Bottom line
Fuel availability usually makes this choice for you, and there is no wrong answer between NG and LP. Either way the generator is the same machine — compare current models on the standby generators page and use the sizing calculator. In NC/SC our install includes the fuel hookup either way; get the free quote.
Frequently asked questions
- Is natural gas or propane better for a standby generator?
- If you have a natural gas line, NG is almost always the right call — unlimited runtime and no tank. Without a gas line, propane is excellent: full rated output, stable storage, and you control your own fuel supply. The same generator runs on either.
- How long will a 500-gallon propane tank run a generator?
- It depends on the generator size and load, but as a planning figure, a typical 20-22kW unit at half load burns roughly 2-3 gallons per hour — so a 500-gallon tank (filled to the standard 80%) commonly supports several days of substantial use. A remote tank monitor takes the guesswork out.
- Does a generator produce less power on natural gas?
- Slightly, yes. The same engine typically rates about 5-10% lower on NG than LP — spec sheets list both (for example 22kW LP / 19.5kW NG). We account for this when sizing, so the difference never surprises you.
- Can I switch fuels later?
- Generally yes — most home standby units convert between NG and LP with a fuel selection change performed by a technician, not a new generator. If you might get a gas line later, buy now and convert when it arrives.
Not sure where to start?
Run our free 60-second sizing calculator or talk to a generator pro for a no-pressure quote.