Prices
Cummins RS25, RS30, RS36 and RS40 prices
The Cummins liquid-cooled RS25 to RS40 cost $17,349.63 to $19,495.69 for the generator alone, depending on the model and the voltage configuration. None of them includes a transfer switch. Installation is quoted after a site survey.
Price by model
| Model | Output | Equipment price | Weight | Dimensions (in) |
|---|---|---|---|---|
| RS25 | 25kW | $17,349.63 to $17,622.48 | 1,109 lb | 72 x 34 x 45.5 |
| RS30 | 30kW | $18,691.85 to $18,812.69 | 1,231 lb | 94 x 34 x 45.5 |
| RS36 | 36kW | $19,257.65 to $19,356.52 | 1,294 lb | 94 x 34 x 45.5 |
| RS40 | 40kW | $19,495.69 | 1,356 lb | 94 x 34 x 45.5 |
Prices are the Cummins suggested retail price, with nothing added at checkout. All four run on natural gas or LP vapor at the same rated output.
Price by voltage configuration
Each configuration is its own Cummins part number. Buy the one that matches the electrical service at the address; a house is almost always 120/240V single phase.
| Model | Voltage | Part number | Price |
|---|---|---|---|
| RS25 | 120/240 1Ph | A051Y239 | $17,622.48 |
| RS25 | 120/208 3Ph | A051Y399 | $17,349.63 |
| RS25 | 120/240 3Ph | A051Y400 | $17,483.32 |
| RS30 | 120/240 1Ph | A051Y401 | $18,812.69 |
| RS30 | 120/208 3Ph | A051Y402 | $18,757.76 |
| RS30 | 120/240 3Ph | A051Y405 | $18,691.85 |
| RS36 | 120/240 1Ph | A051Y417 | $19,356.52 |
| RS36 | 120/240 3Ph | A051Y413 | $19,318.08 |
| RS36 | 277/480 3Ph | A051Y416 | $19,332.71 |
| RS36 | 120/208 3Ph | A051Y418 | $19,257.65 |
| RS40 | 120/240 1Ph | A051Y419 | $19,495.69 |
| RS40 | 120/208 3Ph | A051Y420 | $19,495.69 |
| RS40 | 120/240 3Ph | A051Y421 | $19,495.69 |
| RS40 | 277/480 3Ph | A051Y424 | $19,495.69 |
What installation adds
The generator is one line of the job. These are the other lines on a liquid-cooled install, with the published figures we have for each. The general install ranges are on what a whole house generator costs in DFW; the only installed estimate we publish is for a 20kW air-cooled system, so we quote these four after a survey.
A transfer switch
None of the four includes one. The switch is sized to the electrical service, not the generator:
- RA 200A, single phase, from $1,006.58
- RA 400A, single phase, from $2,292.46
- OTEC 125A to 600A, for three-phase services, from $2,927.10
More gas
At full load on natural gas, per the Cummins spec sheets: RS25 309.5 ft³/hr, RS30 380.9 ft³/hr, RS36 472.3 ft³/hr, RS40 519 ft³/hr, against 268 ft³/hr for an air-cooled RS20A. The supply pressure these four need is 6.0 – 14.0 in H₂O (1.5 – 3.5 kPa). Whether the existing line and meter carry it is the most variable cost on the job; the full chart is in gas line sizing.
A heavier unit to place
These weigh 1,109 to 1,356 lb, against 531 lb for the RS20A, and the RS30, RS36 and RS40 are 94 inches long. The pad is sized to that footprint, and where a truck cannot reach the pad the unit may need a crane, which is a line on the pricing breakdown.
Warranty and service
The base warranty is 2 year standby base warranty, against 5 years / 2,000 hours on the air-cooled range. Cummins extended coverage for these four runs from $1,105.56 for 5 years to $2,772.22 for 10 years of parts, labor and travel (every term). The Cummins operator manual for these engines (A045R242) sets an oil and filter change after the first 50 hours and every 200 hours or 12 months after that, which is part of a service visit.
Permits and the inspection are part of every job; for a unit at or under 50kW, Texas limits what a city may impose (what your city can require).
Questions
How much does a Cummins RS25 cost?
The RS25 equipment price is $17,349.63 to $17,622.48, depending on the voltage configuration: 120/240 1Ph $17,622.48, 120/208 3Ph $17,349.63, 120/240 3Ph $17,483.32. That is the generator only. A transfer switch, the pad, the gas line, the electrical work and the permit are added in the installation, which we quote after a site survey.
Why is there a different price for each voltage?
Cummins builds each configuration as its own part number. A single-phase 120/240V house and a three-phase commercial service need different alternator connections, so you buy the configuration that matches the electrical service at the address. We confirm the service at the survey before anything is ordered.
Does the price include a transfer switch?
No. None of these four includes one. The switch is sized to the electrical service, not the generator: a Cummins RA 200A switch starts at $1,006.58, an RA 400A at $2,292.46, and three-phase OTEC switches start at $2,927.10.
How much more is a liquid-cooled 25kW than an air-cooled 20kW?
On equipment alone, the RS25 starts at $17,349.63 and the RS20A is $5,925.25, a difference of $11,424.38. The RS20A has no transfer switch in the box either. The other differences are the base warranty (2 years against 5 years / 2,000 hours), the weight (1,109 lb against 531 lb) and the gas demand at full load (309.5 ft³/hr against 268 ft³/hr of natural gas).
Is there an RS48?
Not in the range we sell. The Cummins liquid-cooled home standby units we carry step from the RS40 to the RS50. Every one is listed on the generators page with its price.
Prices, part numbers, weights and dimensions from the 2026 Cummins home standby price sheet. Fuel consumption and supply pressure from the Cummins spec sheets RS25 NAS-5775d-EN (4/15); RS30 NAS-5776d-EN (4/15); RS36 NAS-5777d-EN (4/15); RS40 NAS-5778d-EN (4/15) (cummins.com), retrieved 2026-10-09. Extended warranty prices from the Cummins 2026 extended warranty schedule. Service interval from Cummins operator manual A045R242. Prices reviewed 2026-08-28.
Get the installed number for your address
The survey settles the voltage, the switch, the gas line and the pad, and you get the full figure in writing before anything is ordered.
Rather just talk to someone?
Leave a number and we will call you. No sales script, no obligation.
Got it. We will call you. If you would rather not wait, ring (214) 957-4307 and ask for whoever is on generators.