Firman H08051 Dual Fuel 8000W vs Generac GP6500 COsense
The Firman H08051 Dual Fuel 8000W is the more powerful unit: 8,000 running watts against 6,500 — about 19% more capacity for the Firman H08051 Dual Fuel 8000W. The Firman H08051 Dual Fuel 8000W offers more fuel flexibility (gasoline, propane) where the Generac GP6500 COsense runs on gasoline. The Firman H08051 Dual Fuel 8000W runs longer at half load — 12 hours on its 8-gallon tank vs 11.5 hours.
| Firman H08051 Dual Fuel 8000W | Generac GP6500 COsense | |
|---|---|---|
| Type | portable | portable |
| Fuel | gasoline, propane | gasoline |
| Running watts (gas / LP for standby) | 8000 W | 6500 W |
| Starting watts (gas) | 10000 W | 8125 W |
| Running watts (propane) | 7250 W | — |
| Starting watts (propane) | 9050 W | — |
| Noise level | 74 dBA | — |
| Runtime at 50% load (gas) | 12 h | 11.5 h |
| Fuel tank | 8 gal | 7.9 gal |
| Output voltage | 120/240V | 120/240V |
| Transfer-switch-ready outlet | — | 30 A |
| Start type | electric | recoil |
| CO safety shutoff | — | Yes |
| Engine displacement | 439 cc | 389 cc |
| Weight | 212 lb | 172 lb |
Frequently asked questions
Which is more powerful, the Firman H08051 Dual Fuel 8000W or the Generac GP6500 COsense?
The Firman H08051 Dual Fuel 8000W, at 8,000 running watts on its best fuel versus 6,500 W. Remember that dual-fuel and natural-gas ratings are lower than gasoline ratings — the comparison table shows the published per-fuel figures.
Which costs less to run, the Firman H08051 Dual Fuel 8000W or the Generac GP6500 COsense?
Estimated fuel for 24 hours at about 50% load: $51 on gasoline for the Firman H08051 Dual Fuel 8000W vs $53 on gasoline for the Generac GP6500 COsense, at national average prices. These are spec-sheet-derived estimates — the assumptions are on the methodology page, and different fuels make this a cost comparison, not an efficiency ranking.
Where do these specifications come from?
Every record on BackupAtlas is hand-curated from manufacturer documentation and spec sheets, and each generator page links to its source document.