Generac Guardian 18kW (7226) vs Kohler 12RESV 12kW
The Generac Guardian 18kW (7226) is the more powerful unit: 18,000 running watts against 12,000 — about 33% more capacity for the Generac Guardian 18kW (7226). The Generac Guardian 18kW (7226) is the quieter of the two (65 dBA vs 69 dBA — though manufacturers measure noise at different loads and distances).
| Generac Guardian 18kW (7226) | Kohler 12RESV 12kW | |
|---|---|---|
| Price (MSRP) | — | $4,283 |
| Type | home-standby | home-standby |
| Fuel | natural-gas, propane | natural-gas, propane |
| Running watts (gas / LP for standby) | 18000 W | 12000 W |
| Running watts (propane) | 18000 W | 12000 W |
| Running watts (natural gas) | 17000 W | 11000 W |
| Noise level | 65 dBA | 69 dBA |
| Output voltage | 120/240V | 120/240V |
| Automatic transfer switch included | No | No |
| Main-line circuit breaker | 80 A | 60 A |
| Start type | automatic | automatic |
| Engine | Generac G-Force 800 | Kohler KT725 |
| Engine displacement | 816 cc | 725 cc |
| NG use at half load | 169 ft³/h | 128 ft³/h |
| Propane use at half load | 1.7 gal/h | — |
| Weight | 420 lb | 433 lb |
| Warranty | 5 yr | 5 yr |
Frequently asked questions
Which is more powerful, the Generac Guardian 18kW (7226) or the Kohler 12RESV 12kW?
The Generac Guardian 18kW (7226), at 18,000 running watts on its best fuel versus 12,000 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 Generac Guardian 18kW (7226) or the Kohler 12RESV 12kW?
Estimated fuel for 24 hours at about 50% load: $61 on natural gas for the Generac Guardian 18kW (7226) vs $46 on natural gas for the Kohler 12RESV 12kW, 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.