Cummins QuietConnect RS17A 17kW vs Generac Guardian 20kW (7039)
The Generac Guardian 20kW (7039) is the more powerful unit: 20,000 running watts against 17,000 — about 15% more capacity for the Generac Guardian 20kW (7039). The Cummins QuietConnect RS17A 17kW is the quieter of the two (65 dBA vs 67 dBA — though manufacturers measure noise at different loads and distances).
| Cummins QuietConnect RS17A 17kW | Generac Guardian 20kW (7039) | |
|---|---|---|
| Type | home-standby | home-standby |
| Fuel | natural-gas, propane | natural-gas, propane |
| Running watts (gas / LP for standby) | 17000 W | 20000 W |
| Running watts (propane) | 17000 W | 20000 W |
| Running watts (natural gas) | 17000 W | 18000 W |
| Noise level | 65 dBA | 67 dBA |
| Output voltage | 120/240V | 120/240V |
| Automatic transfer switch included | No | Yes |
| Main-line circuit breaker | 100 A | 90 A |
| Start type | automatic | automatic |
| Engine | Cummins QSJ999G | Generac G-Force 1000 |
| Engine displacement | 999 cc | 999 cc |
| NG use at half load | 165 ft³/h | 204 ft³/h |
| Propane use at half load | 1.73 gal/h | 2.37 gal/h |
| Weight | 531 lb | 448 lb |
| Warranty | 5 yr | 5 yr |
Frequently asked questions
Which is more powerful, the Cummins QuietConnect RS17A 17kW or the Generac Guardian 20kW (7039)?
The Generac Guardian 20kW (7039), at 20,000 running watts on its best fuel versus 17,000 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 RS17A 17kW or the Generac Guardian 20kW (7039)?
Estimated fuel for 24 hours at about 50% load: $59 on natural gas for the Cummins QuietConnect RS17A 17kW vs $73 on natural gas for the Generac Guardian 20kW (7039), 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.