Onan (Cummins) Generators

Onan is one of the oldest names in portable and standby power, founded in 1920 and acquired by Cummins in 1986. The brand survives today on residential standby generators (RS series, 13-30 kW) and RV generators (QG and QD series, 2.8-12 kW), where name recognition and dealer loyalty remain strong. Every Onan unit sold today is engineered and supported by Cummins Power Generation.

For commercial and industrial applications above 60 kW, Cummins drops the Onan name entirely. The commercial lineup uses Cummins' own engine platforms — QSB (4.5-6.7L), QSL (8.9L), QSX (15L), and the massive QSK series up to 95 liters — covering everything from small office buildings to utility-scale prime power. These are among the most widely installed commercial generators in North America, backed by over 500 Cummins service locations.

The practical difference for buyers: Onan-branded residential units compete head-to-head with Generac and Kohler in the 13-30 kW home standby market. They run quieter than Generac, cost less than Kohler, and benefit from Cummins' parts depth. The trade-off is fewer residential installers compared to Generac's massive contractor network. For commercial applications, Cummins generators are a default specification alongside Cat and Kohler — choosing between them is usually about dealer relationships, parts standardization, and total cost of ownership over a 20-year lifecycle.