Cummins QuietConnect RS20A 20kW vs Generac Guardian 18kW (7226)
The Cummins QuietConnect RS20A 20kW is the more powerful unit: 20,000 running watts against 18,000 — about 10% more capacity for the Cummins QuietConnect RS20A 20kW.
| Cummins QuietConnect RS20A 20kW | Generac Guardian 18kW (7226) | |
|---|---|---|
| Type | home-standby | home-standby |
| Fuel | natural-gas, propane | natural-gas, propane |
| Running watts (gas / LP for standby) | 20000 W | 18000 W |
| Running watts (propane) | 20000 W | 18000 W |
| Running watts (natural gas) | 18000 W | 17000 W |
| Noise level | 65 dBA | 65 dBA |
| Output voltage | 120/240V | 120/240V |
| Automatic transfer switch included | No | No |
| Main-line circuit breaker | 100 A | 80 A |
| Start type | automatic | automatic |
| Engine | Cummins QSJ999G | Generac G-Force 800 |
| Engine displacement | 999 cc | 816 cc |
| NG use at half load | 172 ft³/h | 169 ft³/h |
| Propane use at half load | 1.81 gal/h | 1.7 gal/h |
| Weight | 531 lb | 420 lb |
| Warranty | 5 yr | 5 yr |
Frequently asked questions
Which is more powerful, the Cummins QuietConnect RS20A 20kW or the Generac Guardian 18kW (7226)?
The Cummins QuietConnect RS20A 20kW, at 20,000 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 RS20A 20kW or the Generac Guardian 18kW (7226)?
Estimated fuel for 24 hours at about 50% load: $62 on natural gas for the Cummins QuietConnect RS20A 20kW 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.