Cummins QuietConnect RS25 25kW Liquid-Cooled vs Generac Guardian 18kW (7226)
The Cummins QuietConnect RS25 25kW Liquid-Cooled is the more powerful unit: 25,000 running watts against 18,000 — about 28% more capacity for the Cummins QuietConnect RS25 25kW Liquid-Cooled. The Cummins QuietConnect RS25 25kW Liquid-Cooled is the quieter of the two (64 dBA vs 65 dBA — though manufacturers measure noise at different loads and distances). Warranty favors the Generac Guardian 18kW (7226): 5 years vs 2.
| Cummins QuietConnect RS25 25kW Liquid-Cooled | Generac Guardian 18kW (7226) | |
|---|---|---|
| Type | home-standby | home-standby |
| Fuel | natural-gas, propane | natural-gas, propane |
| Running watts (gas / LP for standby) | 25000 W | 18000 W |
| Running watts (propane) | 25000 W | 18000 W |
| Running watts (natural gas) | 25000 W | 17000 W |
| Noise level | 64 dBA | 65 dBA |
| Output voltage | 120/240V | 120/240V |
| Automatic transfer switch included | No | No |
| Main-line circuit breaker | 125 A | 80 A |
| Start type | automatic | automatic |
| Engine | — | Generac G-Force 800 |
| Engine displacement | 2400 cc | 816 cc |
| NG use at half load | 185.7 ft³/h | 169 ft³/h |
| Propane use at half load | 2.1 gal/h | 1.7 gal/h |
| Weight | 1109 lb | 420 lb |
| Warranty | 2 yr | 5 yr |
Frequently asked questions
Which is more powerful, the Cummins QuietConnect RS25 25kW Liquid-Cooled or the Generac Guardian 18kW (7226)?
The Cummins QuietConnect RS25 25kW Liquid-Cooled, at 25,000 running watts on its best fuel versus 18,000 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 Cummins QuietConnect RS25 25kW Liquid-Cooled or the Generac Guardian 18kW (7226)?
Estimated fuel for 24 hours at about 50% load: $67 on natural gas for the Cummins QuietConnect RS25 25kW Liquid-Cooled vs $61 on natural gas for the Generac Guardian 18kW (7226), 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.