Onan began in 1920 in the power generating business, and later got largley into engines as well. Onan is one of the best known brands in the world when it comes to power generation and advanced technologies, which is why Cummins sought and did buy them to become known as Cummins Onan. Onan offers a full line of generators including: Home Standbuy, Portable, Commercial, Marine, and RV generators.

Onan is well known for their commitment to the environment and creating products that minimize their related impact. This commitment is demonstrated in their willingness to create new cells, turbines, hybrid generators, and propane powered. Onan has volutnarily offered such technologies as exhaust after treatments and lean fuel burning systems, which have added benefits of burning less oil, producing less smoke, and being quieter!