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Select up to 4 generators to compare specs, power output, noise levels, runtime and more. Your compare URL is shareable.
- Firman WH03662OF
- WEN DF402iX
Quick charts
Each chart uses its own Y-axis scale (so numbers are comparable within a chart).
Running watts
W
Starting watts
W
Noise
dB
Runtime @50%
h
Running watts by fuel
Shows how output changes across gasoline/propane/natural gas (when available).
| Specification | Firman WH03662OF | WEN DF402iX |
|---|---|---|
| General | ||
| Product type | Generator | Generator |
| Fuel | Dual-Fuel | Dual-Fuel |
| Inverter | Yes | Yes |
| Parallel capable | Yes | Yes |
| RV ready | Yes | Yes |
| Running watts | Winner: Winner: 3650 W | 3500 W |
| Starting watts | Winner: Winner: 4500 W | 4000 W |
| Noise (lower limit) | Winner: Winner: 69 dB | 0 dB |
| Weight | 119 lbs | Winner: Winner: 66.1 lbs |
| Run time @50% load | Not available | Winner: Winner: 7 h |
| Run time @25% load | 25 h | Not available |
| Fuel tank | 6 gal | 1.85 gal |
| Fuel gauge | Yes | Yes |
| Approx. dimensions (L × W × H) | 24.5 x 24.1 x 23 | 19.8 x 13.8 x 18.9 |
| Electrical | ||
| Voltage (AC) | 120 | 120 |
| Voltage (DC) | 12 | 5 |
| GFCI outlets | No | No |
| Covered outlets | Yes | No |
| Automatic Voltage Regulation | Yes | Yes |
| THD | <3% % | 1.2 % |
| Engine | ||
| Engine | 208 cc OHV 4-stroke, cast iron sleeve | 212 cc OHV 4-stroke |
| Alternator | Not available | Not available |
| Starting system | Recoil, Electric | Recoil |
| Warranty | ||
| Warranty | 3 years | 2 years |
| Power by fuel | ||
| Gasoline | Not available | Not available |
| Running watts | 3650 W | 3500 W |
| Starting watts | 4500 W | 4000 W |
| Running amps (120V) | Not available | Not available |
| Running amps (240V) | Not available | Not available |
| Peak amps (120V) | Not available | Not available |
| Peak amps (240V) | Not available | Not available |
| Run time @50% load | Not available | 7 h |
| Run time @25% load | 25 h | Not available |
| Propane | Not available | Not available |
| Running watts | 3300 W | 3200 W |
| Starting watts | 4100 W | 3600 W |
| Running amps (120V) | Not available | Not available |
| Running amps (240V) | Not available | Not available |
| Peak amps (120V) | Not available | Not available |
| Peak amps (240V) | Not available | Not available |
| Run time @50% load | Not available | 9.5 h |
| Run time @25% load | 19 h | Not available |
| Other | ||
| Data center | Not available | Not available |
| Indicators | true | true |
| Compliance | CARB, EPA, ANSI/PGMA G300-2023 | EPA |
| Security | Not available | Not available |
| Spark arrestor | Yes | Yes |
| Neutral | Floating | Floating |
| UPC | 840876136621 | 44459994022 |
| Core / High-priority specs | ||
| Running Watts (Gasoline) | 3650 | 3500 |
| Running Watts (Propane) | 3300 | 3200 |
| Starting Watts (Gasoline) | 4500 | 4000 |
| Starting Watts (Propane) | 4100 | 3600 |
| Runtime @ 50% Load (Gasoline) | Not available | 7 |
| Runtime @ 50% Load (Propane) | Not available | 9.5 |
| Runtime @ 25% Load (Gasoline) | 25 | Not available |
| Runtime @ 25% Load (Propane) | 19 | Not available |
| AC Outlet Types | 1x Duplex 120V 20A (5-20R); 1x 120V 30A (L5-30R); 1x 120V 50A (14-50R) | 1x Duplex 120V 20A (5-20R)1x 120V 30A (TT-30R) |
| Electrical & power | ||
| Frequency | 60 | 60 |
| Engine & construction | ||
| Engine Type | OHV 4-stroke | OHV 4-stroke |
| Engine Displacement | 208 | 212 |
| Runtime & fuel system | ||
| Runtime @ 25% Load (Gasoline) | 25 | Not available |
| Runtime @ 50% Load (Gasoline) | Not available | 7 |
| Runtime @ 50% Load (Propane) | Not available | 9.5 |
| Controls & display | ||
| Display Type | Not available | Inverter |
| Safety & compliance | ||
| Overload Protection System | Not available | Low oil, overload and low fuel protection, CO monitoring |
| Low Oil Protection | Yes | Yes |
| Carbon Monoxide Monitoring | Yes | Yes |
| Included equipment | ||
| Included Accessories | Oil, funnel, tool kit, propane hose, RV adapter, battery charging cables, battery, and wheel kit | Funnel, tool kit, propane hose, and 2 altitude kits |
| Warranty & identification | ||
| Residential Warranty | Not available | 2 |
| Commercial Warranty | 3 | 2 |
| Additional specs | ||
| Summary | The Firman WH03662OF is a 3,650-watt dual-fuel inverter generator built for both home backup and job site work. On gasoline, it delivers 4,500 starting watts and 3,650 running watts. On propane, output drops to 4,100 starting and 3,300 running watts. This wattage range powers most household appliances, mid-size power tools, and multiple devices simultaneously. The dual-fuel option gives users flexibility during fuel shortages or when propane's longer shelf life matters.
Because the WH03662OF runs at 69 dBA, placement within 20 to 30 feet of living spaces remains practical for residential use. The inverter produces less than 3% THD, which protects laptops, TVs, and other sensitive electronics from voltage spikes. A 6-gallon tank delivers 25 hours of runtime at 25% load on gasoline and 19 hours on propane. At 50% load, runtime drops to zero hours, meaning users refuel frequently under moderate-to-heavy demand. | The WEN DF402iX is a 4000-watt dual fuel open frame inverter generator designed for RV use, featuring a CO shutdown sensor for safety. |
- Most PowerfulFirman WH03662OF3650W running
- QuietestFirman WH03662OF69 dB
- Longest RuntimeWEN DF402iX7h at 50% load
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Firman WH03662OF
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WEN DF402iX
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