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An outage at dinner time is the wrong moment to shop for backup power, and propane generator cost is the first question most buyers ask: the answer is that it depends on size, fuel and features, not on a single figure, because a small dual-fuel inverter and a large whole-home unit are different machines. This guide shows what sets the figure, using the sizes and ratings the reference listings state, so you can match a generator to the loads you need to run.
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Propane generator cost: the quick answer
Cost rises with running watts, and propane output runs below gasoline output on the same unit: the Westinghouse 12500 (on Amazon) lists 9500 running watts on gasoline and 8500 running watts on propane, and the WEN DF475T (on Amazon) lists 3800 running watts on gasoline and 3500 running watts on propane. Dual-fuel capability, inverter tech, electric start and a longer run time all add to the figure, while a small inverter with recoil start sits at the other end. Work out the running watts your loads need, then compare propane figures, not gasoline figures, since propane is the fuel you plan to burn.
Step 1: Add up the running watts you need
List the loads you want to run at the same time and add their running watts, then check the surge watts for anything with a motor, since motors pull a short spike at startup. The reference listings show the spread: a Westinghouse dual-fuel inverter lists 1,980 running watts on propane, a WEN dual-fuel unit lists 3500 running watts on propane, and a DuroMax dual-fuel (on Amazon) unit lists 13,000 watts. Pick a unit whose propane running watts cover your list with room to spare, not one whose gasoline peak watts merely match it.
| Unit | Gasoline running watts | Propane running watts |
|---|---|---|
| Westinghouse 12500 | 9500 | 8500 |
| WEN DF475T | 3800 | 3500 |
| Westinghouse iGen2800DFc | 2,200 | 1,980 |
| DuroMax XP13000EH | 13,000 | Not stated |
Propane output runs below gasoline output on every unit here that states a figure for each fuel, so size on the propane column when propane is the fuel you will burn.
Step 2: Choose dual fuel or propane only
A dual-fuel unit burns gasoline or propane, and the listings show why that matters for cost: the same unit lists fewer watts on propane than on gasoline, so a dual-fuel unit bought for propane must be sized on its propane figure. A dual-fuel unit also carries the parts for each fuel, such as the 47-inch LPG connection hose the WEN DF475T lists, and the propane hose the Pulsar lists. If you plan to burn propane only, compare propane running watts and ignore the gasoline figure entirely. See the best dual fuel generator conversion kits if you want to convert a gasoline unit.
Step 3: Weigh inverter tech against open frame
Inverter generators adjust engine speed to match the load, and the listings show the pattern: the Westinghouse iGen2800DFc lists 52 dBA and less than 3% THD, the PowerSmart lists 59 dBA from 23 feet and THD under 3%, and the Oxseryn open-frame inverter (on Amazon) lists under 72 dBA from 23 feet. The quieter run and the cleaner output cost more than a plain open-frame build, so match the choice to what you plug in: laptops, phones and tablets need the clean power the listings describe, while heaters and lights do not. A unit with a transfer-switch-ready outlet connects to home wiring, so a licensed electrician should install it.
Step 4: Count runtime, tank and weight
Run time sets how much fuel you carry: the Westinghouse 12500 lists up to 12 hours, the WEN DF475T lists up to 11 hours on a 4-gallon tank at half load, and the Pulsar lists 8 hours on a single tank of gas and 75 minutes on a 1 pound LPG tank at half load. A bigger tank and a longer run time add size and weight: the DuroMax lists 234.0 pounds, and the Pulsar lists 44.0 pounds with a compact carrying case. Eco mode stretches a tank by slowing the engine when the load is light, which the Oxseryn, PowerSmart and Westinghouse inverter listings all state.
Step 5: Check start, outlets and warranty
Electric start, remote start and a wheel kit add convenience and cost: the Westinghouse 12500 lists remote start with a key fob, electric and recoil start, the DuroMax lists push button start, and the WEN DF475T lists electric start with a wheel and handle kit. Outlets decide what you can plug in: the Westinghouse 12500 lists a 120/240V 50A outlet, the WEN DF475T lists a 120V/240V 30A twist lock, and the iGen2800DFc lists a 120V 30A outlet. Warranty length also tracks with the build: the Oxseryn lists a 1-year warranty, the PowerSmart lists 2 years, and the Westinghouse and DuroMax units list 3 years. See the best engine oil for portable generators for the oil the manual lists.
Where a fuel generator runs
Run a fuel generator outdoors only, far from doors and windows, because of carbon monoxide. Never use one indoors or in a partly enclosed area.
Ways to keep the cost down
- Size on propane running watts: size on the propane figure, not the gasoline peak figure, so you do not buy watts you cannot use on propane.
- Match the outlets to your loads: a 120V 30A outlet covers an RV, while a 120/240V 50A outlet suits a home backup build.
- Pick Eco mode where the listing states it: the engine slows when the load is light, so a tank lasts longer.
- Compare warranty length: the listings here run from 1 year to 3 years, with the longer terms on the larger units.
- Stabilize stored fuel: see the best fuel stabilizers for generators for storage between outages.
FAQ: power away from the grid
Does a propane generator cost more than a gasoline one?
It depends on size and features rather than on fuel alone: the Westinghouse 12500 lists 9500 running watts on gasoline and 8500 on propane, so the same machine gives less on propane. Compare propane running watts, not the fuel name, when you size one.
Why does propane give fewer watts than gasoline?
Propane carries less energy per unit than gasoline, so the same engine lists fewer watts on propane: the WEN DF475T lists 3800 running watts on gasoline and 3500 on propane, and the Westinghouse iGen2800DFc lists 2,200 running watts on gasoline and 1,980 on propane.
How long will a propane generator run?
It depends on tank size and load: the Westinghouse 12500 lists up to 12 hours, the WEN DF475T lists up to 11 hours on a 4-gallon tank at half load, and the Pulsar lists 75 minutes on a 1 pound LPG tank at half load. Check the run time the listing states for your load.
What size propane generator do I need?
Add the running watts of the loads you will run at the same time, then pick a unit whose propane running watts cover that total. The listings here run from 1,980 running watts on propane for the Westinghouse iGen2800DFc to 8500 running watts on propane for the Westinghouse 12500.
Is a propane generator quiet?
It depends on the unit: the Westinghouse iGen2800DFc lists 52 dBA, the PowerSmart lists 59 dBA from 23 feet, and the Oxseryn lists under 72 dBA from 23 feet. Check the noise figure the listing states.
Related solar guides
See the best dual fuel generator conversion kits, the best fuel stabilizers for generators, the best engine oil for portable generators and the best deep cycle batteries for a generator.
