Briggs & Stratton PowerProtect+ 18kW
#7 in 15 to 22 kWFull review
For average homes on natural gas that want full rated output and a long warranty with service included.
Norwall $6,899$6,899
The Briggs & Stratton PowerProtect+ 18kW is the better standby generator overall, rated 3.2 to 2.9. The Briggs & Stratton PowerProtect+ 18kW leads on warranty and noise. The Kohler 20RCAL 20kW wins on value. The Kohler 20RCAL 20kW costs $51 less ($6,848 vs $6,899).
Kohler 20RCAL 20kW
#9 in 15 to 22 kWFull review
For average homes with central air that want load management in the box and Kohler’s full coverage warranty.
Norwall $6,848$6,848
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.
Which should you buy?
- Choose the Briggs & Stratton PowerProtect+ 18kW for warranty (7-year warranty vs 5-year warranty) and noise (66 dBA rated in normal operation vs 70 dBA rated in normal operation).
- Choose the Kohler 20RCAL 20kW for value ($342 per kW ($6,848 with transfer switch, 20 kW on propane) vs $383 per kW ($6,899 with transfer switch, 18 kW on propane)).
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 | Briggs & Stratton PowerProtect+ 18kW | Kohler 20RCAL 20kW |
|---|---|---|
| Overall rating | 3.2/5 | 2.9/5 |
| Value 35% | 7 $383 per kW ($6,899 with transfer switch, 18 kW on propane) | 24 $342 per kW ($6,848 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% | 50 66 dBA rated in normal operation | 17 70 dBA rated in normal operation |
| Power quality 10% | 83 under 5% THD | 83 under 5% THD |
| Warranty 25% | 57 7-year warranty | 29 5-year warranty |
Specifications
| Briggs & Stratton PowerProtect+ 18kW | Kohler 20RCAL 20kW | |
|---|---|---|
| Output | ||
| Rated output, propane | 18 kW | 20 kW |
| Rated output, natural gas | 18 kW | 18 kW |
| THD | Under 5% | Under 5% |
| Engine | 993 cc | 999 cc |
| Engine speed | 3,600 rpm | 3,600 rpm |
| Install | ||
| Transfer switch | Included, 200 A | Included, 200 A |
| Load management | No | Yes |
| Remote monitoring | Yes | Yes |
| Enclosure | Aluminum | Aluminum |
| Dimensions | 46 x 27 x 28 in | 47 x 26.0 x 32.3 in |
| Weight | 490 lb | 600 lb |
| Noise and warranty | ||
| Noise, normal operation | 66 dBA | 70 dBA |
| Noise, weekly self-test | 62 dBA | 66 dBA |
| Warranty | 7 years | 5 years |
| Released | 2026-05 | - |