Your choice of generator fuel affects installation cost, operating cost, maintenance, and how long your generator can run during an outage. Here’s a comparison of the three main options for home standby generators.
Natural Gas: The most popular choice for whole‑home standby generators. Natural gas is supplied by your utility through an underground line, so there’s no tank to refill. Pros: Unlimited fuel supply (as long as the utility line is intact), no refueling, clean‑burning, lower maintenance. Cons: Lower power output compared to propane or diesel (natural gas has less energy per cubic foot), may be unavailable in some rural areas, fuel line must be installed. For installation, see the generator installation process.
Propane: Stored in a tank on your property. Pros: Higher energy density than natural gas, longer shelf life (doesn’t degrade like diesel), can be used in rural areas without natural gas service, burns cleaner than diesel. Cons: Tank requires periodic refilling, fuel level monitoring needed, tank installation costs. Propane generators are slightly less powerful than diesel but more powerful than natural gas models.
Diesel: Typically used for larger, commercial‑grade generators, but available for homes. Pros: Most energy‑dense, highest power output, extremely reliable, long engine life. Cons: Fuel degrades over time and requires additives, noisy, higher emissions, fuel storage and delivery required, more maintenance. For most homes, diesel is overkill.
Which Is Best for Your Home? If you have natural gas service, it’s the most convenient choice. If you don’t, propane is excellent—especially with a large tank. Diesel is only recommended for very large homes or those with specific high‑power needs. For help choosing a generator that matches your fuel choice, see generator sizing. For cost implications, see generator installation cost. For permits related to fuel lines, see permits and codes. And for ongoing fuel system care, see generator maintenance.