22 kW Generator
The 22 kW standby generator is one of the most common residential sizes — popular because it provides reliable whole-home coverage including central AC for a wide range of home sizes without crossing into the significantly higher cost of larger commercial-oriented units.
Quick Answer
A 22 kW standby generator is one of the most widely selected residential sizes and may provide whole-home backup for many mid-to-large single-family homes — including central AC systems up to roughly 3.5–4 tons depending on starting surge characteristics and simultaneous loads, along with standard appliances, lighting, and a well or sump pump. Homes with very large AC loads, electric resistance heat, or commercial-level demand may need 24–26 kW. A load calculation verifies fit.
Coverage depends on simultaneous demand and starting surges — a load calculation using your actual appliances is required to confirm.
22 kW provides additional capacity headroom for the HVAC loads that 18–20 kW units may struggle with. It may support most 3–4 ton central AC systems with meaningful capacity remaining for other loads, depending on the unit's starting surge characteristics. At 4+ tons, the starting surge can still approach the generator's capacity during peak conditions — load management modules are available and worth considering for homes with larger AC systems.
On propane at 50% load, a 22 kW generator consumes approximately 1.7–2.2 gallons per hour. A 500-gallon propane tank provides roughly 6–7 days at that rate. Natural gas units draw from the utility line without tank constraints. Verify exact consumption with the manufacturer's model-specific data.
22 kW units are among the most widely stocked sizes — availability from Generac, Kohler/Rehlko, and Cummins is typically strong compared to less common sizes. Installation process follows the same sequence: site assessment, permit, pad, gas line, electrical, transfer switch, inspection. Lead times for equipment vary by region and season.
A 22 kW generator draws approximately 91 amps at full output on 240V. Modern 200-amp panels accommodate this. For 100-amp service, a panel assessment and likely upgrade is important before installation.
Verify sizing with your actual loads
The Generator Size Calculator and Electrical Load Worksheet give you a more accurate result than any size-based rule of thumb.
