Cummins RS20A
Air-cooled · Natural Gas / LP Vapor
Connect Series Air-Cooled
Cummins RS20AC
20kW air-cooled standby generator, Natural Gas / LP Vapor. The volume seller. Two-story suburban homes across Plano, Frisco, McKinney and Southlake.
On natural gas this unit produces 18kW, not 20kW. The headline rating is the propane figure. Almost every DFW home runs natural gas, so size against 18kW unless you are on a propane tank. Most sellers publish only the larger number.
Representative manufacturer image of the range. Enclosure finish, color and dimensions vary by model and configuration — see the specifications below for this unit.
18 kW natural gas · 20 kW LP Natural Gas / LP Vapor Air-cooled Transfer switch included Aluminum
The RS20AC is an air-cooled unit in an aluminum enclosure, which is the right build for a residential yard: no radiator loop to service, a smaller pad, and a footprint of 34.1 x 36 x 27.3 inches at 596 lb.
This is the combo package: it ships with a 200A service-entrance rated, NEMA 3R automatic transfer switch. Buying the switch with the generator is usually the cheaper path, and it removes the most common cause of a delayed install - the wrong switch showing up on site.
It runs on natural gas or LP vapor. On natural gas there is no tank to fill and no runtime limit as long as the utility main holds pressure, which is why it is the default choice on almost every DFW home that already has gas service.
Equipment price
$6,662.42
Equipment only — installation quoted separately
Typical all-in installed cost in DFW
$13,500 - $17,000
$13,500 - $17,000
Equipment above plus professional installation by our licensed electricians. Installation is quoted after a free on-site survey, because gas line runs, panel location and permits differ at every address. We don’t guess, and we don’t pad.
- ✓ Concrete or composite pad
- ✓ Gas line sizing and pressure test
- ✓ Transfer switch and electrical tie-in
- ✓ Permit and city inspection
- ✓ Startup, load test and walkthrough
The five items above are part of the installation quote, not the equipment price.
Reserve this unit — (214) 957-4307Refundable deposit · locks this price 90 days · schedules your free survey · applies 100% to final invoice
Get a free quote firstNot ready to reserve? Have us call you.
Got it. We will call you. If you would rather not wait, ring (214) 957-4307 and ask for whoever is on generators.
Specifications
| Model | Cummins RS20AC |
|---|---|
| Rated output | 20 kW |
| Fuel | Natural Gas / LP Vapor |
| Cooling | Air-cooled |
| Enclosure | Aluminum |
| Weight | 596 lb |
| Dimensions (L×W×H) | 34.1 x 36 x 27.3 in |
| Voltage configurations | 120/240 1Ph |
| Extreme cold package | Available as an upgrade |
| Transfer switch | 200A service-entrance rated, NEMA 3R automatic transfer switch included |
| Application | residential |
| Output — natural gas | 18 kW (75 A at 240 V) |
| Output — LP vapor | 20 kW (83.3 A at 240 V) |
| Sound level | 65 dB(A) 65 dB(A) at 23 ft (7 m) at normal load |
| Cummins model | C20N6HC |
| Engine | QSJ999G — Naturally aspirated, V-twin, air-cooled |
| Displacement | 60.96 in³ (999 cc) |
| Cylinder block | Aluminum |
| Rated speed | 3600 rpm |
| Motor starting | 40 kVA at 30% voltage dip — starts a 5-ton A/C under full pre-load |
| Voltage regulation | ±1.25% no load to full load |
| Frequency regulation | Isochronous, ±1.25% steady state (±1.5% at no load) |
| Harmonic distortion | Less than 5% total harmonic distortion |
| Main breaker | Single 100 A circuit breaker, UL certified |
| Battery required | Group 51R, 450 CCA at 32°F (0°C) — part A052Y816, bought locally |
| Clearance to structure | 18 inches from a building (meets NFPA 37) |
| Gas supply pressure | NG 3.5 – 12.0 in H₂O (0.87 – 3.0 kPa) · LP 6.0 – 12.0 in H₂O (1.49 – 3.0 kPa) |
| Fuel use at full load | 268 ft³/hr natural gas · 112 ft³/hr LP |
| Operating temperature | -40°F to 122°F (-40°C to 50°C) |
| Wind rating | Evaluated to withstand 180 MPH wind loads per ASCE 7-10 |
| Derating | Full rated power to 60°F (15°C) and sea level. Derate 3.5% per 1,000 ft and 1% per 10°F above that. |
| Certifications | UL 2200, CSA 22.2 and B149.1, EPA emissions, NFPA 37 |
| Warranty | 5 year / 2,000 hour limited warranty. RA automatic transfer switches carry a separate 2 year warranty. |
Available configurations
This model ships in a single factory configuration.
| Part number | Voltage | Phase | Price |
|---|---|---|---|
| A071Z402 | 120/240 | 1Ph | $6,662.42 |
All prices are for the equipment only.
Built in
What the RS20AC does that the spec table does not show
Intelligent Load Management
The generator can control up to 4 loads and continuously monitors how much power each one needs, then restores only the loads it has capacity to run. This is what makes a 20kW unit cover a house with two air conditioners.
Patented Crank-Only exercise mode
The weekly exercise cycle can crank the engine and run diagnostics without actually starting it, which reduces wear, fuel use and the noise of the exercise run.
Remote monitoring, built in
Remote monitoring is standard on every unit. From a computer, tablet or phone you can check status, change the exercise schedule and start the generator manually.
5-ton air conditioner start
Rated to start and run a 5-ton A/C under full pre-load — the load that decides generator sizing in Texas.
Accessories and maintenance parts for this unit →
Specifications on this page are taken from the Cummins published specification sheet for
the air-cooled Connect range.
Download it from Cummins →
Questions about the RS20AC
How much does a Cummins RS20AC cost installed in Dallas-Fort Worth?
The RS20AC equipment price is $6,662.42. Installed in DFW, a typical 20kW job runs $13,500 - $17,000 all in. The spread comes from four things: how far the pad sits from your gas meter, whether the gas line carries the added load or has to be upsized, the run from the generator to your electrical panel, and what your city charges and requires for permits and inspection. We put the installation number in writing after a free site survey.
What will the RS20AC actually run?
Whole-house coverage for a typical 2,500-3,500 sq ft DFW home with two AC systems, using load management. Final confirmation comes from a load calculation against your actual panel, which we do at the survey.
Does the RS20AC include a transfer switch?
Yes. This is the combo configuration and it ships with a 200A service-entrance rated, NEMA 3R automatic transfer switch. Service-entrance rated means it can serve as your main disconnect, which often simplifies the install and can reduce what the electrician has to rework at the panel.
Is the RS20AC in stock?
Availability changes weekly. A refundable deposit reserves a specific unit and locks the equipment price for 90 days, which is the practical way to hold one while the survey and permit work happen. If we cannot source it in a reasonable window, you get the deposit back.
Compare
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Want the RS20AC priced for your address?
Equipment is $6,662.42. The installation number depends on your property, and the only honest way to get it is to come look. That visit is free.