Standby Generators — Whole-Home, Estate & Commercial Backup Power

Standby generators for homes and small commercial buildings

A standby generator is permanently installed outside the building, fed by natural gas or LP, and paired with an automatic transfer switch so the building recovers from an outage without anyone touching a control. This collection carries 86 standby units, led by Cummins and Briggs & Stratton with Generac completing the range, from 10kW-class home units to large three-phase commercial packages.

What decides the unit

• Connected load, not house size. A load calculation on the circuits you want backed up - heating, cooling, well pump, refrigeration, medical equipment - sets the kW class. Load management lets a smaller generator cover a larger service.
• Air-cooled vs liquid-cooled. Air-cooled units dominate 10-26kW residential work and are cheaper and simpler. Liquid-cooled units start around 22-30kW and are the right answer for long run times, higher ambient temperatures and commercial duty cycles.
• Fuel. Natural gas is convenient but derates the engine and may limit kW where supply pressure is low. LP carries better power density and needs an on-site tank and delivery plan.
• Transfer switch pairing. Service-entrance rated switches replace the main disconnect; standalone switches sit downstream. The generator, switch and service rating must be designed together.

Installation and permitting

Installation is a licensed electrician plus a gas fitter job. Expect a permit, a concrete pad with clearance from the building and from windows per the manufacturer's instructions, an exhaust direction that does not recirculate, and a final inspection that covers grounding, the transfer switch listing and fuel piping. Noise ordinances in some municipalities set a distance or dBA limit - check before the pad is poured.

Freight and delivery

Standby units ship on a pallet and usually need LTL with liftgate or a dock, and the larger liquid-cooled units need a delivery plan for a job site without equipment. We quote freight against the address and unloading conditions, and the quote confirms current lead time before you commit.

Looking specifically for the Generac range? Browse the Generac generators hub for standby units, portables and transfer switches in one place.

Choosing a portable machine? See the 7-12kW portable generator guide.

Sizing up? See the 22-26kW standby guide.