Standby Generator Sizing for Clark County Homes

Quick answer: Standby or whole-house generator sizing for most homes falls between 16kW and 26kW. While square footage provides a useful starting point, the right size ultimately depends on your home’s electrical loads, including central air, heating type, and major appliances. A 22kW unit typically covers 2,000- to 3,500-square-foot homes with gas heat; all-electric homes or those adding EV charging often need 26kW or a load management controller.

Whole-house generator sizing ultimately comes down to your home’s total electrical demand during an outage. For most homes in Clark County, that number lands somewhere between 16kW and 26kW, depending on square footage, whether you run central air conditioning, and whether your heat and cooking are gas or electric. A generator that is too small will trip under load or shut down the moment your AC compressor kicks on. One that is too large costs more upfront and burns more fuel than necessary. Getting whole-house generator sizing right the first time is the difference between a system that quietly does its job for 20 years or more with proper maintenance and one that needs frequent troubleshooting during outages.

How Whole-House Generator Sizing Works

Every appliance has two power numbers: running watts and starting watts. Running watts are what a device draws once it is up and operating steadily. Starting watts, sometimes called surge or inrush watts, are the short burst a motor pulls the instant it switches on. A central air conditioner might run at 3,500 to 6,000 watts but briefly demand two to three times that when the compressor starts. A generator has to be sized for both, which is why load calculations for standby generator sizing are never as simple as adding up nameplate wattage.

What Size Generator Do You Need for Your Home?

General sizing bands, based on square footage and typical appliance loads, give you a reasonable starting point before a licensed electrician runs the actual numbers for your panel. A whole-house generator sized at 16 to 22 kW is generally sufficient for homes between 2,000 and 2,500 square feet, while many homes between 3,000 and 3,500 square feet fall in the 22 to 26 kW range. Larger all-electric homes or those with multiple HVAC systems, EV charging, or other heavy electrical loads may require 30 to 36 kW or more.

Home Size	Typical Generator Size (kW)	Coverage Level
Under 1,500 sq ft	10 to 15kW	Essentials plus most appliances
1,500 to 2,500 sq ft	16 to 22kW	Whole-house coverage with moderate AC
2,500 to 3,500 sq ft	22 to 26kW	Whole-house coverage with central AC
Over 3,500 sq ft	26kW and up	Whole-house, dual HVAC, EV charging

Table figures are general planning ranges. Your actual generator size depends on a load calculation specific to your panel and appliances, not square footage alone.

22kW vs 26kW Generator: Which One Fits Your House

The 22kW vs 26kW generator decision usually comes down to three factors: your heating fuel, your AC tonnage, and whether you plan to add EV charging or other electric-heavy upgrades later. A 22kW generator can typically handle both heating and cooling in homes that use natural gas, propane, or oil for heat, since it is not carrying the full load of an electric furnace. If your home relies on electric resistance heat, that same 22kW unit may fall short during a cold-weather outage when the furnace is drawing the most.

A 26kW standby generator produces roughly 108 amps at 240 volts, which can often accommodate a home’s typical loads plus Level 2 EV charging, depending on charger size and whether load management is used. If you are sizing a generator for a larger Clark County home, or one where a hot tub, EV charger, and central AC will all draw from the same panel, the extra 4kW of headroom is often worth the modest jump in equipment and fuel cost.

Load Management Can Change the Math

A load management controller sequences which large appliances start first, preventing your AC compressor and electric water heater from surging at the same moment. This kind of intelligent load sequencing can reduce equipment and installation costs by avoiding the need for a larger generator, often saving several thousand dollars. For homes on the edge between two generator sizes, this is frequently the more cost-effective fix than simply buying the bigger unit.

Why Professional Sizing Still Matters

Square footage tables get you in the right neighborhood, but they cannot account for a well pump, an all-electric kitchen, or a home office running server equipment around the clock. A licensed electrician runs an actual load calculation against your panel, evaluating your panel, connected loads, and service capacity before recommending a final kilowatt rating. If you are also weighing portable versus standby generators, sizing is one more reason a standby unit tends to win out for whole-house coverage. And once a generator is installed, it still needs regular upkeep. Backup generators do need scheduled maintenance to perform when a storm knocks out your power.

If you need help determining what size generator you need for your house or installing said generator, contact MAS Pro.

Frequently Asked Questions

Is a 22kW generator big enough for a whole-house?

For most homes between 2,000 and 3,500 square feet with gas or propane heat, yes. All-electric homes or those adding EV charging often need to size up or add load management.

What size generator do I need for my house if I have central AC?

Central AC is usually the single largest load in a whole-house generator sizing calculation. A 3 to 4 ton unit can require 3,500 to 6,000 running watts plus a starting surge, which is why most homes with full AC land in the 22kW to 26kW range.

Can a smaller generator power a whole-house with load management?

Often, yes. A load management controller can sequence appliance startups so a 22kW unit covers loads that would otherwise require 26kW or more, though this depends on your specific appliance mix.