Overview#
The Cummins RS20A is the largest air-cooled generator in the QuietConnect RS Series, delivering 20 kW of standby power from the same compact 999 cc V-twin platform used in the RS13A and RS17A. It is the top choice in the air-cooled lineup for homeowners who need to start and run a 5-ton central air conditioner under full pre-load while maintaining power to the rest of the home.
The RS20A runs on natural gas or propane vapor (field selectable) at 3,600 rpm and produces 65 dB(A) at 23 feet -- identical sound performance to the smaller RS13A and RS17A. The aluminum enclosure is wind-rated to 180 mph per ASCE 7-10 and allows 18-inch setback from structures per NFPA 37. Cold weather operation is rated to 0 F (-18 C) standard.
Natural gas consumption at full load is 268 CFH. LP consumption at full load is 112 cubic feet per hour (approximately 5.3 gallons per hour). At 531 lbs the RS20A shares the same weight and footprint as the RS17A, making it a straightforward upgrade path for homeowners who need more capacity.
Technical Specifications#
| Parameter | Value |
|---|---|
| Standby Rating | 20 kW |
| Voltage | 120/240V single phase |
| Frequency | 60 Hz |
| Rated Amps (NG) | 75.0 |
| Rated Amps (LP) | 83.3 |
| Engine Model | QSJ999G |
| Displacement | 999 cc (60.96 in³) |
| Configuration | Naturally aspirated, V-twin |
| Cooling | Air-cooled |
| Bore x Stroke | 3.54 in x 3.09 in |
| Rated Speed | 3,600 rpm |
| Voltage Regulation | ±1.25% |
| THD | < 5% |
| Sound Level | 65 dB(A) at 23 ft (7 m) |
| Dimensions (L x W x H) | 34.1 x 36.0 x 27.3 in |
| Weight | 531 lbs |
| Wind Rating | 180 mph (ASCE 7-10) |
| Cold Weather | 0 F (-18 C) standard |
Fuel consumption at full load:
| Fuel | Consumption |
|---|---|
| Natural Gas | 268 CFH |
| LP Vapor | 112 CFH |
Our Service Experience#
The RS20A is the most popular air-cooled QuietConnect model in our service area. It hits the sweet spot for Northern California homes in the 2,000-3,500 square foot range with central A/C. The 20 kW output handles most whole-house loads without the complexity and cost of a liquid-cooled system.
Maintenance is identical to the RS13A and RS17A -- oil change at 200 hours or annually, air filter and spark plug inspection, and battery load testing. The air-cooled platform has no coolant, radiator, or water pump, which eliminates the most common failure modes found on liquid-cooled residential units.
For homes that need more than 20 kW, the next step up is the RS25 -- a liquid-cooled unit with a 2.4-liter inline 4-cylinder engine. The jump from air-cooled to liquid-cooled adds maintenance complexity but provides substantially more power and motor starting capacity.
Frequently Asked Questions#
What is the standby rating of the RS20A? 20 kW at 120/240V, 60 Hz, single phase. The NG rating delivers 75 amps; the LP rating delivers 83.3 amps.
How does the RS20A compare to the RS17A? Both use the same QSJ999G engine and share identical dimensions, weight, and sound levels. The RS20A delivers 20 kW vs 17 kW and is specifically rated to start a 5-ton A/C under full pre-load.
What is the warranty on the RS20A? 5-year / 2,000-hour limited warranty from Cummins. Extended options available up to 10 years through authorized dealers.
