Tri-fuel means one generator, three ways to fuel it: gasoline off the shelf, propane from the same tanks your grill uses, and natural gas straight from your home's utility line via a quick-connect valve. If gasoline runs out during a regional emergency, you're not stuck. Here are five real picks across the price range, from a budget dual-fuel starting point up through a full-capacity tri-fuel unit with genuine indefinite-runtime potential.
Predator 5000 DF (Dual-Fuel Entry Point)
What it does well: 3,900 running watts on gasoline with a fuel-flexible propane option, CO SECURE automatic carbon monoxide shutdown, and Harbor Freight's lowest price point in this class. A solid entry if you want fuel flexibility without paying for the natural gas hookup you may never use.
The trade-off: No natural gas option, and Harbor Freight's 90-day product warranty is shorter than Champion or Honda's 3-year coverage.
Firman Tri-Fuel 7850/6300W
What it does well: Genuine tri-fuel flexibility with electric start and a CO alert sensor. Parallel-ready means you can add a second matched unit later for more capacity instead of buying a bigger single generator upfront. Firman's engineering leans toward high peak watts per dollar.
The trade-off: Firman's inverter line tests slightly higher on total harmonic distortion than Champion's — fine for most appliances, but check compatibility if you're running sensitive medical electronics (see our medical equipment generator guide).
Predator 11,500 TF
What it does well: A genuine step up in capacity over the 5000 DF, with a 50-amp 14-50R outlet for direct connection to a transfer switch. On natural gas, this unit can run indefinitely off your home's gas line during an extended outage — the single biggest practical advantage of going full tri-fuel.
The trade-off: Heavy (250+ lbs class), open-frame, and loud compared to inverter models. Best suited to a fixed home-backup role rather than portability.
Predator 13,000 Tri-Fuel
What it does well: The clearest illustration of the fuel-type wattage drop: 10,000 running watts on gas falls to 9,100 on propane and 7,800 on natural gas — still substantial capacity for a large home's essential circuits, even on the lowest-output fuel. Remote start, digital display, fuel-type selector switch, and a quick-connect for both propane and natural gas.
The trade-off: Premium price and 250+ lb weight put this closer to a semi-permanent home backup unit than something you casually move around.
Champion Dual-Fuel 7500W (Tri-Fuel Kit Compatible)
What it does well: Champion's inverter line consistently tests under 3% total harmonic distortion — the industry benchmark for safely running laptops, modern CPAP machines, and other sensitive electronics. Champion also backs this class with lifetime free technical support by phone, unusual at this price point, plus a 3-year warranty that beats Predator's 90 days.
The trade-off: Ships as dual-fuel (gas + propane); natural gas requires an aftermarket kit rather than being built in, unlike the Predator and Firman tri-fuel units above.
What to check before buying any of these
- Confirm your outlet needs. Larger tri-fuel units include a 50A 14-50R outlet for direct transfer switch connection; smaller units may only have standard 120V outlets plus a single 30A connection.
- Check the CO shutdown feature specifically. Not every "safety sensor" is an automatic shutdown — some are alarm-only. See our CO safety guide for why this distinction matters.
- Verify warranty terms if you're considering a future propane or NG aftermarket conversion on a unit that doesn't ship tri-fuel from the factory — see our conversion kit guide.
The fuel-type wattage drop, explained
Every tri-fuel generator loses output as you move from gasoline to propane to natural gas — both alternative fuels have lower energy density per unit burned. Budget roughly 10–15% less running wattage on propane and 20–25% less on natural gas versus the gasoline rating. If you plan to primarily run on NG for its indefinite-runtime advantage, size your generator to the NG wattage figure, not the flashier gasoline number on the box.
For the deeper question of whether tri-fuel is worth the premium over dual-fuel for your situation, see our tri-fuel vs. dual-fuel comparison.
How to choose between these five
Start with the natural gas question, since it's the biggest fork in this list. If you don't have gas service at home, the Predator 5000 DF or Champion 7500W dual-fuel unit already covers your practical fuel-flexibility needs at a lower price than the genuine tri-fuel units — you're not missing out on much by skipping natural gas capability you'll never connect. If you do have gas service, the Firman 7850/6300W is the best entry point into true tri-fuel, with the Predator 11,500 TF and 13,000 Tri-Fuel scaling up for larger homes or extended-outage regions.
Weight and portability matter more than spec sheets suggest once you're actually moving one of these. The smaller dual-fuel units in the 100–110 lb range are manageable for one person with the built-in wheel kit; the larger tri-fuel units at 250+ lbs are effectively semi-permanent once positioned, better suited to a fixed home-backup location than something you'll wheel in and out of a shed regularly.
Running cost comparison across fuel types
| Fuel | Approx. cost per hour at moderate load | Availability during regional emergencies |
|---|---|---|
| Gasoline | $2–$4 | Can run out at local stations during widespread outages |
| Propane | $3–$6 | Stored on-site, doesn't degrade, but tank capacity limits runtime |
| Natural gas | $1–$3 | Indefinite as long as utility service continues, which it usually does |
Natural gas is both the cheapest per-hour fuel option and the most resilient during exactly the kind of widespread regional emergency where gasoline supply becomes unreliable — the combination that makes tri-fuel's premium worth paying for anyone with existing gas service.
Frequently Asked Questions
What is a tri-fuel generator?
A tri-fuel generator can run on gasoline, propane (LPG), and natural gas, switched via a selector switch or by swapping the fuel connection. This gives you three independent fuel sources — if gas stations are empty after a storm, you can switch to propane tanks or a natural gas quick-connect at your house.
Do I need a plumber to use the natural gas option on a tri-fuel generator?
You need a one-time installation of a 1/2-inch natural gas quick-connect valve on an exterior wall, the same type of valve used for outdoor gas grills, which typically costs $100–$200 for a licensed plumber to install. After that, connecting the generator during an outage is as simple as snapping in the included hose.
Does a tri-fuel generator run at full power on all three fuels?
No — output drops on propane and drops further on natural gas compared to gasoline, because both alternative fuels have lower energy density. Expect roughly 10-15% less running wattage on propane and 20-25% less on natural gas versus the gasoline rating. Size your generator with this in mind if you plan to primarily run it on NG or propane.
Is tri-fuel worth the extra cost over dual-fuel?
If your home has an existing natural gas line, yes — it gives you a fuel source that never runs out as long as utility gas is flowing, on top of the propane and gasoline flexibility dual-fuel already offers. If you don't have gas service, the extra cost mainly buys you a feature you'll never use, and a good dual-fuel unit covers the same practical bases.