Kohler Generators

Kohler generators are the power quality benchmark in the standby generator market. With total harmonic distortion consistently below 3% — against an industry norm of 5-8% — Kohler is the default specification for hospitals, surgical centers, and data centers where clean power is not optional. The company's enclosures are also the quietest in the industry at comparable power ratings, which matters for installations near occupied spaces, residential property lines, or noise-sensitive commercial tenants.

## Company History

Kohler Co. was founded in 1873 in Kohler, Wisconsin, originally as a manufacturer of cast-iron plumbing products. The company entered the power generation business in 1920 when it built a generator to power its own manufacturing operations and quickly recognized the commercial opportunity. That makes Kohler one of the oldest continuous generator manufacturers in the industry — over a century of engineering experience behind the current product line. The power systems division grew to encompass generators, engines, automatic transfer switches, paralleling switchgear, and energy storage systems. Kohler's headquarters remained in Kohler, Wisconsin throughout its history as a privately held company.

In 2024, Kohler Co. sold its power systems division to Platinum Equity, a private equity firm. The division now operates as an independent entity, with a corporate rebrand to Rehlko announced in September 2024. The engineering teams, manufacturing facilities, and authorized dealer network remain unchanged. For buyers evaluating Kohler generators today, the acquisition is a corporate ownership change — not a technical one. The sub-3% THD alternators, quiet enclosures, and Decision-Maker controllers that earned Kohler its reputation are the same products from the same factories.

## Product Lineup

Kohler's generator portfolio covers every segment of the power generation market:

**Residential standby** — Air-cooled units in the RCA and RCL series serve homes from 14 kW to 60 kW, running on natural gas or propane. These are Kohler's answer to Generac's Guardian line, with quieter enclosures and cleaner power output at a price premium of roughly 10-15%.

**Commercial and industrial** — Liquid-cooled diesel and gas generators range from 10 kW to 4,000 kW. The KD Series is the industrial diesel flagship, with models from 800 kW to 4,000 kW powered by Kohler's own KD-series engines. Below 800 kW, Kohler pairs established OEM engines (John Deere, Volvo Penta) with its own alternators and controls. Natural gas models in the KG Series serve commercial applications from 40 kW to 400 kW.

**Marine** — Purpose-built marine generators provide vessel power with corrosion-resistant enclosures and seawater cooling systems.

**Mobile and towable** — Portable generator sets serve construction sites, outdoor events, and emergency response where permanent installation is not practical.

Beyond generators, Kohler manufactures automatic transfer switches and paralleling switchgear. The paralleling capability is significant for large facilities — hospitals, campuses, data centers — that need multiple generators operating in concert with load sharing and redundancy. The Decision-Maker 6000 controller manages these multi-unit configurations from a single interface.

## Strengths and Considerations

Kohler's core advantages are power quality, noise performance, and NFPA 110 compliance. The sub-3% THD specification is not marketing — it is a measurable electrical characteristic that matters for MRI machines, CT scanners, precision manufacturing equipment, and enterprise IT systems. Kohler industrial units are designed to meet NFPA 110 Level 1 requirements, reaching full rated load within 10 seconds of utility loss. For life-safety applications in hospitals and emergency facilities, these specifications often make Kohler the required choice in the engineering specification.

The honest limitation is cost and ecosystem lock-in. Kohler units price similarly to Caterpillar and above Cummins and Generac by 10-15%. The Decision-Maker controller, while powerful, is proprietary — replacement modules, programming, and integration work must go through Kohler-certified channels. Buyers who prefer open-architecture controls (like the Basler DGC-2020 found in Blue Star units) should weigh that dependency carefully. Kohler's dealer network, while strong, is also smaller than CAT's roughly 200 US locations or Generac's 10,000-plus installer base.

For industrial buyers choosing between Kohler and Caterpillar, the decision often comes down to power quality versus resale value. Kohler wins on THD and noise; CAT wins on secondary market pricing and dealer density. For buyers choosing between Kohler and Cummins, the comparison is power quality versus vertical integration and cold-weather performance — Cummins builds its own engines and alternators and offers the best cold-start ratings in the industry. Kohler's power quality advantage is most decisive in healthcare, semiconductor, and data center applications where THD directly affects equipment reliability.