A dual fuel generator runs on gasoline or propane, and a tri fuel model adds natural gas. Buyers choose them for the fuel, not the noise: propane keeps for years in a cylinder, and a gas line does not run dry in an outage. But the noise question follows you onto the new fuel, and the makers answer it less clearly than you would hope. Our parent guide to the quietest generators for camping and RVs covers gasoline inverters; this one covers the machines that can run on something else.
We read the product pages and manuals for the dual fuel and tri fuel generators from Champion, WEN, Westinghouse, Firman, DuroMax, Pulsar and Generac. We quote each figure in the maker's words, with the load and the distance where the maker gives them, and we rank figures only against others taken at the same stated load and distance.
Our picks are listed above, with full specifications for each.
What the makers state, grouped
A noise figure without a load and a distance is a claim. Here is what each maker gives for its dual and tri fuel models.
- Quarter load and 22 feet. WEN, in its manuals: "58 dBA (25% load from 22 feet away)" for the DF450i and DF452iX, "62.5 dBA" on the same wording for the DF525iX, and "68 dBA" for the open frame DG4500iX. Our WEN generator decibels page lists every WEN figure, including the DF400iX and DF451i, which share the 58.
- 25% load and 25 feet. Westinghouse, once: its spec table for the iGen2800DFc lists "operational noise 25 percent load 25ft dba" as 62. Our Westinghouse generator decibels page explains why the rest of its range says "as low as" instead.
- 23 feet, no load. Champion: 53 dB(A) for the 2000W 201230, 2400W 201271 and 2500W 201530, 201323 and 201122 dual fuel inverters; 59 for the 3400W 100396; 61 for the 4500W 201319 and the 8500W 201177. Our Champion generator decibels page lists all of them.
- A load, no distance. Firman: "58dB ¼ load" for the WH03342, "64dB ¼ load" for the tri fuel WT03571. Westinghouse: "around 60 dBa at 25% load" for the tri fuel iGen8200TFc. DuroMax: "Volume @ 25% Load (db) 61 dB" for its XP9500iHT tri fuel inverter. WEN: 64 decibels at quarter load for the TF1300iX. Pulsar: "Rated at 63 dB at half load" for its PG105TiSRCO, a half-load figure that sits in a group of its own. WEN's DF280iX lists 60 decibels "at no load", another group of one. Our Firman generator decibels page covers Firman's whole range.
- Neither. Champion's tri fuel 201534 page says 61 dB(A) and, unlike its dual fuel pages, no distance. Pulsar's PGD95BiSCO says "Volume (dB) 62". DuroMax's XP2300iH says 52 dB. Westinghouse's iGen2800DFc description adds "as quiet as 52 dBA" on top of its stated 62.
- Nothing. Generac gives no figure for the iQ5200, as our Generac generator decibels page found across its portables. Predator's site refused our requests, so we could not read its pages.
The three distances matter. WEN measures at 22 feet, Champion at 23 and Westinghouse at 25, and we do not convert between them. Our explainer on why you cannot compare dB ratings across brands covers how the same engine can get different numbers.
We looked for a maker that publishes one figure on gasoline and another on propane. We found none. WEN's manuals give a single Decibel Rating beside separate wattage lines for gasoline and LPG. Champion's spec tables list a single Noise Level beside separate propane watts and amps. Westinghouse, Firman and DuroMax do the same. So the figure you read is the machine's figure, and it tells you nothing about which fuel was in it during the test.
What propane does change, on paper, is output. That makes the quarter-load figure slightly less useful on propane. A quarter load is a quarter of the rated output, and the rated output is lower on propane. Plug a refrigerator into the DF450i and it takes the same watts on either fuel, but on propane it is a larger share of a 3,150 watt rating than of a 3,500 watt one. The makers do not tell you what that does to the noise, and we will not guess. The practical point is to size on the propane figure if propane is what you will run.
Propane derating, as each maker states it
Every maker publishes running or rated watts for each fuel. These are their numbers, gasoline first.
- Champion 201530: 1,850 W, then 1,665 W on propane. 201230: 1,700 and 1,530. 201319: 3,500 and 3,150. 201177: 7,000 and 6,300. 201534: 4,000, 3,600 on propane and 3,240 on natural gas. Starting watts stay the same on both fuels for each of these models.
- WEN DF450i and DF452iX: 3,500 and 3,150 rated watts. DG4500iX: 3,650 and 3,285. DF280iX: 2,250 and 2,000. DF525iX: 4,200 and 4,200, which WEN calls "matched output on either fuel". TF1300iX: 10,500, 9,000 on propane and 8,000 on natural gas.
- Westinghouse iGen2800DFc: the description says 2,200 and 1,980 running watts; the spec table says 2,000 and 1,800. iGen8200TFc: 6,600, 5,940 and 5,280 on natural gas.
- Firman WH03342: 3,300 and 3,000 running watts. WT06375: 6,300, 5,700 and 4,900 on natural gas.
- DuroMax XP13500iH: 10,500 and 10,000. Generac iQ5200: 3,900 and 3,500 on LP.
Most of these work out to about 10% less on propane. Natural gas costs more: 19% on Champion's 201534 and 20% on the Westinghouse iGen8200TFc. The DF525iX is the only model here rated at full output on propane.
Run time: where propane wins at night
The quiet benefit of propane is not lower noise but fewer trips outside. A generator that runs out at 2 a.m. has to be refueled in the dark, and a 20-lb cylinder often outlasts the small gasoline tank on these units. Champion lists the 201530 at 11.5 hours at 1/4 load on its 1.05 gallon tank and 25 hours on propane. The 201230 lists 34 hours on propane. The 201319 lists 14 hours on gasoline and 21 on propane.
It is not always so. Champion's tri fuel 201534 lists 20 hours on its 3.7 gallon gasoline tank and 15 on a 20-lb propane tank, and the 8500W 201177 lists 14 and 12. WEN quotes half load rather than quarter: the DF525iX runs 5.9 hours on gasoline and 9.6 on a 20-lb tank, both with eco mode on. Compare runtimes only at the same load.
Natural gas: what a tri fuel model needs
A tri fuel generator on a house gas line runs as long as the utility supplies gas, which suits a multi-day outage. Champion's manual for the 201534 is plain about what that takes: "A dedicated NG fuel supply line with shut-off valve is mandatory for proper operation." It asks for a supply pressure of 5 to 7 inches water column and a minimum flow rate of 135,000 BTU/hr, says improper supply sizing is the number one cause of hard starting or poor output, and says gas line connections should be made by a certified plumber familiar with local codes.
That is a fixed connection point, and it decides where the generator sits. If the only place a plumber can put the outlet is under a bedroom window, you have chosen your noise problem along with your fuel. Our guide to the quietest portable generators for home backup covers 240 V units and transfer switches. A permanently installed standby unit is the other route, ranked in our home standby generator guide.
Where the generator and the tank go
Every placement rule from the parent guide still applies, and propane adds one. The Consumer Product Safety Commission's words: "Use generators outside only, at least 20 feet away from homes with exhaust facing away," and "Never use portable generators inside homes or garages, even if doors and windows are open." Champion's manuals add, for the cylinder: "NEVER place the LPG (liquefied petroleum gas) connector hose OR LPG cylinder tank in the path of the muffler exhaust gas stream of the generator during engine operation."
The hose decides the rest. WEN includes a six-foot LPG hose with the DF525iX, and Champion includes a 6.6 ft. hose with the 201534 and sells a 12 ft. extension kit. So the tank sits near the generator, 20 feet from the house, not by the back door.
At 20 feet, the figures in this guide are a fair guide to what reaches your wall, but a window and a wall each change what gets through. For a bedroom at night, our quiet bedroom page covers how low the background sits once the house is asleep, and roughly every 10 dBA is a doubling of perceived loudness. The 8 dB(A) gap between Champion's 53 and 61 models, both at 23 feet, is most of a doubling. For what your neighbors hear, see our yard noise overview.
Eco mode on either fuel
Eco mode is how an inverter reaches its quiet end, and the makers describe it as a feature of the generator, not of one fuel. Champion's manual says the Eco Mode button "can be activated to turn on economy control in order to minimize fuel consumption and noise while operating the unit during times of reduced electrical output," and that it should be off for periods of high electrical load. WEN quotes the DF525iX's propane runtime with eco mode on. Leave it on whenever the load is light, on either fuel.
How much should you spend?
Around $600 buys Westinghouse's iGen2800DFc at its $599 MSRP, the one dual fuel unit with a load and a distance under $700. Around $790 to $830 buys a WEN with a fully stated figure: the DF525iX at $789.99 or the DF450i at $829.77 regular. Around $1,000 buys the DF452iX with CO Watchdog, and around $1,100 buys Firman's WH03342. Around $1,600 buys the tri fuel Westinghouse iGen8200TFc. Champion shows no prices on its own site.
Mistakes buyers make
Assuming propane is quieter. No maker we read says so with a figure.
Sizing on the gasoline watts. If propane is your main fuel, size on the propane figure, which is usually about 10% lower.
Comparing 22, 23 and 25 feet. WEN's 58, Champion's 53 and Westinghouse's 62 are different tests.
Putting the cylinder in the exhaust. Champion's manual forbids it in capitals.
Treating a gas line as a plug-in. The manual asks for a dedicated line, a stated pressure and flow, and a certified plumber.
New to the units? Read dBA explained, or set the figures beside everyday sounds in our decibel chart.
How we chose
We read the manufacturer's product page for every dual fuel and tri fuel generator here, and the owner's or operator's manual where the page left out the noise condition or the fuel requirements. We recorded each figure in the maker's words, with the load and the distance where given, and ranked only within a group that shares both. We compared running watts on each fuel, run time at the maker's quoted load, weight, outlets and the carbon monoxide shutoff, and took prices from the maker's own site.
We did not measure any of these generators, on gasoline, propane or natural gas, and we did not convert any figure from one distance or load to another. Every number here is the maker's own, quoted as published.
