Looking for a Generac 20kW? The Closest Whole Home Sizes

Best for
Installers supplying their own transfer switch

Best for
20kW shoppers wanting transfer switch bundled

The Generac 22kW Whole Home Generator in this listing includes a transfer switch in the title, along with cellular capability. It delivers 22,000 watts at 240 volts, connects to your existing LP or natural gas supply, and starts within seconds of detecting a power loss. It keeps running until utility power returns, which means the fridge, HVAC, lights, router and your gaming PC stay on through long outages.

Generac lists electronic fuel and ignition control for efficient fuel use, automatic voltage regulation, a fully enclosed design and low oil shutdown. Oil level sensors help keep it ready, and a sloped roof and rear intake reduce ice and snow intrusion, with improved cold starts. Built-in cellular lets you monitor and control it through the Mobile Link app, although that requires a Mobile Link premium subscription. It weighs 451 pounds and measures about 46 by 26 by 31 inches, and comes with a 5-year limited warranty.

This is the default pick for a 20kW search. The transfer switch is the part that safely connects the generator to your panel, so seeing it in the listing simplifies planning. The listing does not specify the switch’s amperage, so confirm that with your installer.

• 22kW at 240 volts
• Transfer switch named in the listing
• Cellular Mobile Link monitoring
• 5-year limited warranty

This Generac 22kW Whole Home Generator listing shows the same 22kW output, 240-volt rating, 451-pound weight, cellular capability and 5-year warranty, but its title does not mention a transfer switch. Every other feature matches: automatic starting, electronic fuel and ignition control, oil level sensors and the cold-weather intake design.

That makes it the version for buyers whose installer supplies a transfer switch or who already have compatible equipment. Since the listing does not specify one is included, assume it is not. If you are comparing the monitoring options, our guide to Generac generator remote monitoring explains how the app side works.

Choose this listing only when the switch is sorted separately. Otherwise, the bundled version is simpler.

Best for
Large homes with heavy HVAC loads

The Generac 26kW Whole Home Generator is the largest standby unit here, at 26,000 watts and 240 volts. It shares the automatic LP or natural gas operation, cellular monitoring, oil sensors, cold-weather design and 5-year warranty, and it adds automatic idle control to its feature list.

It weighs 524 pounds, the heaviest in the group. The extra capacity suits large homes with several air conditioners, electric appliances and a home office or streaming setup all running at once. For a home where a 20kW unit would be tight, this is the size that removes the worry.

If your load calculation fits under 22kW, this is more generator than you need.

• 26kW at 240 volts
• Automatic idle control
• Cellular monitoring

Best for
Homes needing slightly under 20kW

The Generac 18kW Whole Home Generator sits just below the 20kW mark, delivering 18,000 running watts at 240 volts. It weighs 426 pounds, the lightest standby unit here, and its feature list includes automatic idle control, dual fuel, overload protection and a super quiet label.

It also mentions compatibility with the Generac home energy ecosystem, including PWRcell battery systems, for monitoring and controlling home energy. Two listing quirks: the starting wattage is listed as 180,000 watts, which is clearly a typo for a generator rated at 18kW, and the listing does not state the warranty term the others list. Confirm both with the seller.

Pick it if a professional load calculation lands comfortably under 18kW. If it comes in near 20kW, the 22kW is the safer choice.

• 18kW at 240 volts
• Lightest standby unit here
• PWRcell battery compatibility

Best for
Headroom above 22kW without going 26kW

The Generac 24kW Whole Home Generator fills the gap between 22kW and 26kW, with 24,000 watts at 240 volts and 60 hertz. It shares the automatic operation, electronic fuel and ignition control, automatic idle control, oil sensors, cellular monitoring and 5-year warranty.

The listing does not specify weight or dimensions. It suits homes that are slightly beyond what a 22kW handles comfortably, such as a house with a big AC system plus a detached workshop or media room. For a broader look at standby models, see our Generac standby generator guide.

• 24kW at 240 volts
• Automatic idle control
• 5-year limited warranty

Best for
Portable backup for gaming rigs and essentials

The Generac 12,500 Starting Watt Tri-Fuel Portable, the GP9500E, is the only non-standby option. It runs on gasoline, liquid propane or natural gas with a dial turn, delivering 9,500 running watts and 12,500 starting watts on gasoline from a 500cc Generac OHV engine. Automatic voltage regulation stabilizes output for sensitive equipment.

COsense detects rising carbon monoxide and shuts the generator down, and electric start uses an included 12V battery. The 7.5-gallon tank gives up to 9.5 hours at 50% load on gas, and a natural gas hookup extends runtime. Outlets include two 120V 20A GFCI duplexes, a 30A twist-lock and a 50A outlet. It weighs 219 pounds with never-flat wheels, works with Generac HomeLink manual transfer switches, and carries a 3-year residential warranty.

It suits renters or buyers who want to keep a PC, router, fridge and a few circuits running. It is not a true whole home replacement for a 20kW standby, and you will need to start and connect it yourself.

• Tri-fuel: gas, propane, natural gas
• 9,500 running / 12,500 starting watts
• COsense CO shutdown
• Manual transfer switch compatible