Kohler Energy (Rehlko): Brand Guide for Premium Standby Power
Published July 31, 2026 — PES Supply Brand Guides
Kohler has built standby generators for over a century, and the name carries a premium connotation that few competitors can match. Founded in 1873 and headquartered in Kohler, Wisconsin, Kohler Co. established its power division to deliver commercial-grade reliability to the residential market. In 2024, Kohler's energy business — including generators, engines, and power systems — was rebranded as Rehlko under Platinum Equity ownership, while continuing to manufacture under the trusted Kohler brand name on its generator products. This guide covers Kohler's current generator lines, recent developments, certifications, warranty terms, popular models at PES Supply, technical comparisons, and installation notes.
At PES Supply, we stock Kohler standby generators and accessories among our 50,000+ SKUs from 169 authorized brands. Browse our generators collection and pair every unit with the right transfer switch.
1. Company Overview
Kohler Co. was founded in 1873 by John Michael Kohler in Kohler, Wisconsin, originally as a cast-iron and plumbing manufacturer. The company entered engine manufacturing in the 1920s and built its first standby generator in 1921, giving it over a century of power-generation heritage. Kohler's energy division produces residential, commercial, and industrial generators, as well as engines used across outdoor power equipment. In 2023–2024, Kohler completed the sale of its energy business to Platinum Equity, which rebranded the entity as Rehlko while retaining the Kohler brand on generator products and maintaining the Kohler, Wisconsin manufacturing footprint.
Kohler's power division serves residential, commercial, industrial, and marine markets with a global network of over 10,000 dealers. The brand is positioned at the premium end of the standby market, emphasizing build quality, longevity, and clean power output. Kohler conducts accelerated generator testing under rigorous load conditions to meet a stated 20-year life expectancy for its residential units.
2. Current Product Lines
Kohler's generator portfolio spans residential air-cooled through industrial diesel:
- RES Series (Residential Air-Cooled): The flagship home standby line, including the popular 20RESCL (20 kW) and the 26RES (26 kW). Powered by the Kohler OHVI (Overhead Valve Industrial) engine, running on natural gas or LP, with the Kohler OnCue Plus monitoring platform.
- RESV / RESL Variants: Aluminum or composite enclosure versions of the RES line for corrosion resistance in coastal environments.
- 14RES / 20RESCL: Mid-range air-cooled models (14 kW and 20 kW) popular for whole-home backup on standard lots.
- Industrial Diesel (KD Series): Heavy-duty diesel generator sets from 20 kW to 4 MW for mission-critical commercial, healthcare, and data center applications, with long run times and high durability.
- OnCue Plus: Kohler's remote monitoring and management app for smartphones and computers, enabling status checks, exercise scheduling, and alerts.
- Portable Generators: Gas-powered portables including the PRO5.2/PRO5.2E inverter, backed by a 3-year limited warranty and a network of 10,000+ dealers.
3. Recent Releases (2025–2026)
Under Rehlko ownership, Kohler's energy business has continued product-line refinement and digital integration. Kohler's 26 kW home standby generator, launched in 2023, remains the brand's top residential air-cooled output and continues as a flagship model through 2025–2026, delivering premium motor-starting capacity for large homes. The OnCue Plus platform has been enhanced for cloud connectivity, and the Power Solutions Center online tool supports industrial generator sizing and specification.
Rehlko has signaled continued investment in clean energy integration, positioning Kohler standby units to pair with solar and battery storage as part of resilient home energy systems. The 20-year life-expectancy testing standard remains a differentiator, and the brand continues to emphasize its premium positioning on build quality and power cleanliness. Kohler's portable line, including the PRO5.2 inverter, carries a 3-year residential and commercial warranty with free loaner units for warranty repairs exceeding 24 hours.
4. Certifications & Listings
Kohler standby generators meet the following certifications and code requirements:
- UL 2200: Stationary engine generator assemblies listed by Underwriters Laboratories.
- EPA: Certified to current EPA emission standards for stationary engines.
- CARB: Compliant for sale in all 50 states including California.
- CSA: Listed for Canadian installations.
- NEC Article 702: Optional Standby Systems compliance via listed transfer switch.
- NFPA 37: Engineered for clearance permitting close-to-building installation.
- IEEE: Clean power output with low harmonic distortion suitable for sensitive electronics.
- Premium 3-Year Warranty (Portables): Portable models backed by a 3-year limited warranty across residential and commercial use.
5. Warranty Terms
Kohler backs its standby generators with industry-standard coverage and a premium service promise:
- Residential Air-Cooled (RES Series): 5-year limited warranty — one of the most comprehensive in the residential class, covering parts, labor, and travel for the full five years.
- Commercial/Industrial (KD Series): Warranty terms scale with model and application; extended coverage available through authorized dealers.
- Portable Generators: 3-year limited warranty for both residential and commercial applications, including free loaner units for warranty repairs exceeding 24 hours.
- Extended Warranty: Available through Kohler's dealer network for extended coverage beyond the standard term.
Kohler's willingness to cover parts, labor, and travel for the full residential warranty term — rather than stepping down to parts-only in later years — is a meaningful differentiator versus some competitors.
6. Popular Products at PES Supply
These Kohler models are among the most specified at PES Supply:
| Model | Power | Fuel | Enclosure | Key Feature |
|---|---|---|---|---|
| 20RESCL | 20 kW | NG / LP | Aluminum | Premium residential standby; OnCue Plus |
| 26RES | 26 kW | NG / LP | Aluminum | Top air-cooled output; large-home capacity |
| 14RES | 14 kW | NG / LP | Aluminum/Composite | Entry-level whole-home standby |
| KD Series (Industrial) | 20 kW–4 MW | Diesel | Sound-attenuated | Mission-critical commercial/healthcare |
| PRO5.2 Inverter (Portable) | 5.2 kVA | Gasoline | Enclosed | 3-yr warranty; loaner for 24+ hr repairs |
The 20RESCL is Kohler's signature residential standby — quiet, clean-power, and backed by a 5-year parts/labor/travel warranty. Pair every generator with a UL 1008 transfer switch from our transfer switches collection.
7. Technical Comparison: Kohler vs. Competitors
| Criteria | Kohler RES | Generac Guardian | Cummins QuietConnect | Briggs PowerProtect |
|---|---|---|---|---|
| Top air-cooled kW | 26 kW | 28 kW | 20 kW | 26 kW |
| Standard warranty | 5 yr (parts+labor+travel) | 5 yr | 5 yr / 2,000 hr | 10 yr |
| Engine | Kohler OHVI | G-Force / EFIC | Cummins-designed | Vanguard |
| Life-expectancy testing | 20-year | Standard | Standard | Standard |
| Remote monitoring | OnCue Plus | Mobile Link | Connect Cloud | EnergyTrak |
| Dealer network | 10,000+ | 7,000+ | 500+ | Extensive |
Kohler's differentiators are premium build quality, a stated 20-year life-expectancy testing standard, full parts/labor/travel coverage for five years, and the broadest dealer network (10,000+). Its top air-cooled output (26 kW) trails only Generac's 28 kW. The warranty term matches Generac and Cummins but is shorter than Briggs & Stratton's 10-year — though Kohler's coverage is more comprehensive in the later years.
8. Installation Notes
- Sizing: The 20RESCL handles most 2,500–3,500 sq ft homes; the 26RES supports larger estates and dual-AC loads. The 14RES is an entry-level whole-home choice for smaller footprints. Use our sizing calculator.
- Fuel type: Natural gas and liquid propane; verify gas supply pressure and pipe sizing with the fuel provider. Output is rated on both fuels.
- Transfer switch: Match to a UL 1008 ATS rated 100A–200A. Kohler offers matched transfer switches; third-party UL 1008 units are also compatible. See our transfer switch guide.
- Electrical: Install per NEC Article 702 with proper grounding and bonding per Article 250. Kohler's clean power output (low THD) protects sensitive electronics.
- Placement: Maintain NFPA 37 clearances. Aluminum enclosures (RESV/RESL) are recommended for coastal and high-corrosion environments.
- Surge protection: Add a Type 2 SPD at the service panel to protect the OnCue Plus controller and home electronics.
9. Frequently Asked Questions
Is Kohler now called Rehlko?
Kohler's energy business was acquired by Platinum Equity and rebranded as Rehlko, but the generators continue to be manufactured and sold under the Kohler brand name. Product quality, manufacturing, and the dealer network remain consistent.
How long is the Kohler standby warranty?
Residential air-cooled RES series generators carry a 5-year limited warranty covering parts, labor, and travel for the full term — more comprehensive than competitors that step down to parts-only in later years.
What is OnCue Plus?
OnCue Plus is Kohler's remote monitoring and management platform, accessible via smartphone app or computer. It provides real-time status, exercise scheduling, and maintenance alerts.
Are Kohler generators good for sensitive electronics?
Yes. Kohler standby generators produce clean power with low total harmonic distortion (THD), making them safe for computers, home theater, and other sensitive electronics.
What is the largest Kohler air-cooled home standby?
The 26RES delivers 26 kW, making it Kohler's top residential air-cooled output — sufficient for large homes with multiple central air conditioners and high motor-starting demands.
10. Shop Kohler at PES Supply
For premium build quality, clean power, and comprehensive 5-year parts/labor/travel coverage, Kohler remains the standby brand of choice for quality-conscious homeowners and contractors. PES Supply stocks Kohler RES series generators, transfer switches, and accessories to support your specification.
Standard delivery is 7–10 business days nationwide. Every Kohler product ships with full manufacturer warranty and is backed by our technical support team.
Ready to spec a Kohler? Browse our full Kohler inventory:
- Shop All Kohler Products
- Standby & Portable Generators
- Transfer Switches
- Surge Protection
- Electrical Accessories
By the PES Supply Editorial Team. Specifications and warranty terms are subject to change — verify current details with our sales team before specification.