Generac 18kW Standby 7324
#5 in 15 to 22 kWFull review
For average homes with one central air conditioner that want a whole-house switch included.
Amazon $5,975.10$5,975.10
The Generac 18kW Standby 7324 and the Cummins Quiet Connect RS20AC 20kW are evenly matched, rated 3.2 and 3.2. The Generac 18kW Standby 7324 costs $687.32 less ($5,975.10 vs $6,662.42).
Cummins Quiet Connect RS20AC 20kW
#6 in 15 to 22 kWFull review
For homes with central air that want a quiet 20 kW unit with monitoring included and a service-entrance switch in the box.
Norwall $6,662.42$6,662.42
Prices were last checked November 1, 2026 and are subject to change; the price and availability shown by the retailer at the time of purchase apply.
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every 15 to 22 kw standby generator; a clear win is highlighted. How we rank explains each one.
| Factor weight | Generac 18kW Standby 7324 | Cummins Quiet Connect RS20AC 20kW |
|---|---|---|
| Overall rating | 3.2/5 | 3.2/5 |
| Value 35% | 29 $332 per kW ($5,975 with transfer switch, 18 kW on propane) | 28 $333 per kW ($6,662 with transfer switch, 20 kW on propane) |
| Transfer switch 15% | 100 includes a 200 A transfer switch | 100 includes a 200 A transfer switch |
| Noise 15% | 58 65 dBA rated in normal operation | 58 65 dBA rated in normal operation |
| Power quality 10% | 83 under 5% THD | 83 under 5% THD |
| Warranty 25% | 29 5-year warranty | 29 5-year warranty |
Specifications
| Generac 18kW Standby 7324 | Cummins Quiet Connect RS20AC 20kW | |
|---|---|---|
| Output | ||
| Rated output, propane | 18 kW | 20 kW |
| Rated output, natural gas | 17 kW | 18 kW |
| THD | Under 5% | Under 5% |
| Engine | 817 cc | 999 cc |
| Engine speed | 3,600 rpm | 3,600 rpm |
| Install | ||
| Transfer switch | Included, 200 A | Included, 200 A |
| Load management | No | No |
| Remote monitoring | Yes | Yes |
| Enclosure | Aluminum | Aluminum |
| Dimensions | 46.4 x 26.3 x 30.7 in | 34.1 x 36.0 x 27.3 in |
| Weight | 426 lb | 596 lb |
| Noise and warranty | ||
| Noise, normal operation | 65 dBA | 65 dBA |
| Noise, weekly self-test | 55 dBA | - |
| Warranty | 5 years | 5 years |
| Released | 2025 | - |