The Kohler 26RCA is a 26-kilowatt residential air-cooled standby generator and the largest air-cooled unit in Kohler's (Rehlko's) current residential lineup. Per spec sheet G4-315, it uses the Kohler CH1006 999 cc V-twin at 3,600 RPM, 120/240 V single phase, multi-fuel (NG/LP), in an aluminum sound enclosure.
At 26 kW sustained output with air cooling, the engine is working harder than the 14- and 20-kW siblings, and ambient-temperature derate becomes more relevant. For installs in inland areas with hot summers, a liquid-cooled platform (RCL) at comparable kW is generally a better long-term choice.
Per Kohler's RCA owner manual, with Kohler PRO 10W-50 oil and the PRO extended-life filter, oil and filter changes are on a 300-hour / 2-year interval. Without the PRO oil/filter, the manual specifies 100 hours / yearly oil and 200 hours / yearly filter. We default to the PRO regimen.
We install the 26RCA where the customer needs the larger air-cooled output but the site is mild enough — typically coastal Monterey Peninsula and Santa Cruz County. Inland installs of this kW band trend toward liquid-cooled.
Engineering specifications
Physical
Length
47 in
Width
26.2 in
Height
32.3 in
Dry weight
670 lb
Acoustic
Sound @ 7m, full load
67 dBA
Enclosure
Sound-attenuated
Fuel system & runtime
BTU/hr @ full load
290,000
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Get pricing & lead time on the Kohler 26RCA
Tell us about the application — kW, voltage, application, install timeline — and we'll respond within one business day with budgetary pricing, lead time, and any sizing notes.
Adjust load percent and tank size to estimate runtime. Pre-filled with this model's spec where available.
Estimate runtime on this tank
Fuel demand at 75% load
273,000 BTU/hr≈ 273.0 cf/min @ 1,000 BTU/cf
On utility natural gas the runtime is generally unlimited provided the supply line and meter can deliver this BTU/hr at the engine's required inlet pressure (typically 5–14" WC residential, up to 5 psi commercial). Confirm against the OEM's published fuel-pressure spec.
Service intervals
Manufacturer-recommended intervals for the Kohler 26RCA under standby duty. Field intervals may differ based on load profile, ambient conditions, and fuel quality.
Oil & filter
Every 200 hours or 24 months
Load bank test
Every 12 months
Common failure modes
What we've seen fail on this platform. Use as a service-planning reference, not a diagnostic — actual failure modes depend heavily on duty cycle and maintenance history.
Component
Symptom
Typical hours
Severity
Battery
Failed to start during outage
—
minor
Spark plugs
Hard starting, rough idle
—
minor
Cooling system
Overtemp under sustained full load, especially summer
—
moderate
Frequently Asked Questions
What engine is in the 26RCA?
Per Kohler's G4-315 spec sheet, the 26RCA uses a Kohler CH1006 V-twin air-cooled engine (999 cc, 10.5:1 compression, 3,600 RPM). Maximum engine output is listed at 26.1 kW on LP and 24.5 kW on natural gas; the genset's electrical rating is 26 kW standby.
Is the 26RCA the largest Kohler air-cooled residential generator?
As of the current Kohler/Rehlko residential catalog, yes — the 26RCA is the top of the air-cooled RCA family. Larger residential units shift to the liquid-cooled RCL platform.
Why does air-cooled top out around this size?
Air cooling relies on fins and a fan to shed heat. As engine output rises, dissipating heat under sustained full-load operation in warm ambient becomes the limiting factor; liquid cooling (radiator + coolant) handles that more effectively at higher kW.
25 kW residential/light commercial standby on NG or propane. Sized for whole-house backup and small retail with motor-starting loads.
25 kW gaseous-fueled standby generator with Brushless Wound-Field alternator and PowerBoost excitation. Sized for residential and light commercial backup on natural gas or propane.
Single-phaseresidentialcommercial-small
Kohler
Kohler 24RCL
Liquid-cooled 24 kW standby -- quieter and heat-rated where air-cooled units derate. Kohler KG2204 at 1800 RPM.
24 kW standby · Natural Gas / LPG · Liquid-cooled
24 kW residential standby for medium-to-large homes requiring quiet operation and full-load performance in hot climates on NG/LP.
24 kW residential liquid-cooled standby generator. Kohler's whole-house backup for medium homes on natural gas or propane.
30 kW residential/light commercial standby on NG or propane. Sized for whole-house backup and small retail with motor-starting loads.
30 kW gaseous-fueled standby generator with Brushless Wound-Field alternator and PowerBoost excitation. Mid-range CCL series unit for residential and light commercial backup.
Single-phaseresidentialcommercial-small
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