Compare Generators Side-by-Side
Select up to 4 generators to compare specs, power output, noise levels, runtime and more. Your compare URL is shareable.
- Firman WH03662OF
- Genmax GM5500XiD
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 @25%
h
Running watts by fuel
Shows how output changes across gasoline/propane/natural gas (when available).
| Specification | Firman WH03662OF | Genmax GM5500XiD |
|---|---|---|
| General | ||
| Product type | Generator | Generator |
| Fuel | Dual-Fuel | Dual-Fuel |
| Inverter | Yes | Yes |
| Parallel capable | Yes | Yes |
| RV ready | Yes | Yes |
| Running watts | 3650 W | Winner: Winner: 4000 W |
| Starting watts | 4500 W | Winner: Winner: 5500 W |
| Noise (lower limit) | 69 dB | Winner: Winner: 68 dB |
| Weight | 119 lbs | Winner: Winner: 68 lbs |
| Run time @50% load | Not available | Not available |
| Run time @25% load | Winner: Winner: 25 h | 11 h |
| Fuel tank | 6 gal | 2.2 gal |
| Fuel gauge | Yes | Yes |
| Approx. dimensions (L × W × H) | 24.5 x 24.1 x 23 | 23.1 x 18.5 x 17.8 |
| Electrical | ||
| Voltage (AC) | 120 | 120 |
| Voltage (DC) | 12 | 5 |
| GFCI outlets | No | No |
| Covered outlets | Yes | Yes |
| Automatic Voltage Regulation | Yes | Yes |
| THD | <3% % | ≤3% % |
| Engine | ||
| Engine | 208 cc OHV 4-stroke, cast iron sleeve | 160 cc OHV 4-stroke engine. |
| Alternator | Not available | Not available |
| Starting system | Recoil, Electric | Recoil |
| Warranty | ||
| Warranty | 3 years | 1 years |
| Power by fuel | ||
| Gasoline | Not available | Not available |
| Running watts | 3650 W | 4000 W |
| Starting watts | 4500 W | 5500 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 | 8 h |
| Run time @25% load | 25 h | 11 h |
| Propane | Not available | Not available |
| Running watts | 3300 W | 3600 W |
| Starting watts | 4100 W | 4950 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 | 12.5 h |
| Run time @25% load | 19 h | 17.5 h |
| Other | ||
| Data center | Not available | Not available |
| Indicators | true | true |
| Compliance | CARB, EPA, ANSI/PGMA G300-2023 | CARB, EPA, ANSI/PGMA G300-2023 |
| Security | Not available | Not available |
| Spark arrestor | Yes | Yes |
| Neutral | Floating | Floating |
| UPC | 840876136621 | 860013299040 |
| Core / High-priority specs | ||
| Running Watts (Gasoline) | 3650 | 4000 |
| Running Watts (Propane) | 3300 | 3600 |
| Starting Watts (Gasoline) | 4500 | 5500 |
| Starting Watts (Propane) | 4100 | 4950 |
| Runtime @ 50% Load (Gasoline) | Not available | 8 |
| Runtime @ 50% Load (Propane) | Not available | 12.5 |
| Runtime @ 25% Load (Gasoline) | 25 | 11 |
| Runtime @ 25% Load (Propane) | 19 | 17.5 |
| 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 |
| Engine Displacement | 208 | 160 |
| Engine Oil Type | Not available | SAE 10W/30 |
| Runtime & fuel system | ||
| Runtime @ 25% Load (Gasoline) | 25 | 11 |
| Runtime @ 50% Load (Gasoline) | Not available | 8 |
| Runtime @ 50% Load (Propane) | Not available | 12.5 |
| Safety & compliance | ||
| Overload Protection System | Not available | Low oil and overload protection |
| Low Oil Protection | Yes | No |
| Carbon Monoxide Monitoring | Yes | Yes |
| Included equipment | ||
| Included Accessories | Oil, funnel, tool kit, propane hose, RV adapter, battery charging cables, battery, and wheel kit | Oil, funnel, tool kit, propane hose, and wheel kit |
| Warranty & identification | ||
| Commercial Warranty | 3 | Not available |
| 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 Genmax GM5500XiD is a 4000-watt dual-fuel inverter generator that handles essential household loads, power tools, and RV systems simultaneously. Running on gasoline or propane, it delivers clean 3% THD output safe for laptops and televisions. At 68 pounds with a wheel kit included, this unit moves easily between storage and deployment. |
- Most PowerfulGenmax GM5500XiD4000W running
- QuietestGenmax GM5500XiD68 dB
- Longest Runtimeh at 50% load
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Firman WH03662OF
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