Dual Fuel vs Tri Fuel Generators: Which One Should You Buy?
By the Generator Hubs team · Updated · 6 min read
Dual fuel generators run on gasoline or propane. Tri fuel models add natural gas. Compare output, fuel storage, cost and convenience before you choose.
Fuel flexibility is one of the most useful features a backup generator can have. During long outages, gas stations may be closed or out of fuel. Being able to switch fuels keeps the lights on.
What dual fuel means
A dual fuel generator runs on gasoline or liquid propane (LPG). You choose the fuel with a selector switch, and many models let you change fuel while running.
- Gasoline gives the highest output and is easy to find, but it goes stale in a few months without stabilizer.
- Propane stores for years in a tank, burns cleaner and keeps the carburetor clean. Output is usually around 10 percent lower than on gasoline.
What tri fuel adds
A tri fuel generator also runs on natural gas (NG). If your home already has a natural gas line, a plumber can install a quick-connect so the generator draws from the utility supply. There is no refueling at all during an outage, as long as gas service continues.
Natural gas gives the lowest output of the three fuels, often 15 to 20 percent below gasoline. The manufacturer lists the exact figure for each fuel on the product page.
How to choose
- You have a natural gas line: tri fuel is the most convenient choice for home backup.
- No gas line, but you can store propane tanks: dual fuel covers you well and costs less.
- Occasional use for tools or camping: a single-fuel or dual fuel inverter is often enough.
Check the output on the fuel you will use
When you compare models, look at the running watts on the fuel you plan to use most, not just the gasoline peak figure. Use our sizing guide to check that the lowest-output fuel still covers your essentials.
Frequently asked questions
Can I switch fuels while the generator is running?
Many recent dual and tri fuel models allow it. Check the manual of the specific model before trying.
Does natural gas give less power?
Yes. Natural gas has less energy per volume, so output is typically 15–20% lower than on gasoline.
