20-28kW Standby Generators

77 products

About 20-28kW Standby Generators

20-28kW is the whole-home standby class — enough capacity to run a full 200A-service house, including central air, through any outage. This collection features the Generac Guardian 20/22/24/26kW, Kohler 20RESC series, and Cummins air-cooled standby units, running on natural gas or liquid propane with automatic weekly self-testing.

Every unit here pairs with an automatic transfer switch — many listings bundle a 200A service-rated ATS. These generators ship freight on a pallet and install on a prefab or poured pad by a licensed electrician and gas fitter.

Frequently Asked Questions

Is a 20-26kW generator enough for my whole house?

For most homes with 200A service, yes. A 20-24kW unit runs the HVAC, kitchen, lighting, well pump, and water heater simultaneously in a typical 2,000-3,500 sq ft home. Electric heat, dual AC systems, or large shop loads can push you to 26kW+ or require load-management modules — send us your panel details and we'll size it.

Natural gas or liquid propane — which should I choose?

If you have a gas meter, natural gas is the default: unlimited runtime and no refills. Propane is the answer for rural homes without gas service — a 500-gallon tank runs a 22kW unit for roughly 3-5 days under typical load. All units in this class are field-convertible between the two fuels.

Does the transfer switch come with the generator?

Some listings in this collection are generator + 200A ATS bundles; others are generator-only. Check the product title and description — if you need a transfer switch separately, see our 200-225A transfer switch collection. The ATS is what makes backup automatic; without it the generator won't start or switch on its own.

What does installation involve?

A licensed electrician sets the unit on a pad, installs the ATS at your main panel, and pulls an electrical permit; a gas fitter runs the fuel line with its own permit in most jurisdictions. Typical install runs 1-2 days plus inspection. Most utilities and municipalities require permits for permanently installed standby generators.

How is a standby generator delivered?

Freight on a pallet, curbside. These units weigh 450-600 lbs, so you'll need equipment or a crew on site to move the unit to its pad — the freight driver is only obligated to get it off the truck at the curb. Liftgate delivery is available on request.

What warranty do standby generators carry?

Generac Guardian units carry a 5-year limited warranty; Kohler and Cummins offer comparable 5-year coverage on air-cooled residential models. Warranty service is handled through each manufacturer's authorized dealer network nationwide.