What Size Generator Do You Need for Your Henderson, NV Home?
Get the size wrong in either direction and it costs you: too small, and the unit can't carry your AC on the hottest day of the year — the exact day you need it most. Too big, and you've overpaid for capacity you'll never use. Here's how we actually size a system, not a generic rule of thumb.
The Short Answer
Most Henderson single-family homes land in the 17–22kW range for whole-house coverage. Homes with a single AC unit and no pool can sometimes go smaller; homes with dual AC, a pool, or a casita often need 24kW+. Essential-circuits-only systems (no AC) can start around 10–14kW.
How Sizing Actually Works
1. Add up running watts, not just square footage. Every appliance and circuit you want covered has a running wattage (what it draws continuously) and a starting wattage (the surge when it kicks on, usually 2–3x running watts for motors). A generator has to be sized to the highest simultaneous load, factoring in starting surge — not just the sum of everything added together.
2. AC is almost always the largest single load. A typical 3-ton AC unit draws roughly 3,500–4,000 starting watts. This is the single biggest factor in Henderson sizing specifically, because unlike milder climates, skipping AC coverage isn't really an option here — see the AC-specific breakdown below.
3. Whole-house vs. essential circuits is a real decision, not just a budget one. Whole-house coverage runs everything automatically with no load management. Essential-circuits systems cost less upfront but require choosing in advance what's covered — typically AC, refrigerator, key outlets, and garage door.
Typical Sizing by Home Profile
| Home Profile | Typical Size | Covers |
|---|---|---|
| Essential circuits only, no AC | 10–14 kW | Fridge, key outlets, garage door, some lighting |
| Single-story, 1 AC unit, <2,500 sq ft | 17–22 kW | Whole house including AC |
| Two-story or dual AC, 2,500–4,000 sq ft | 22–26 kW | Whole house, both AC units |
| Large home, pool, casita, or 3+ AC units | 26–38 kW+ | Whole house plus pool equipment |
The Henderson-Specific Factor: AC Load
We size differently here than installers in milder climates do, because going without AC during a summer outage isn't a comfort issue in Henderson — it's a safety one. If you're also running pool equipment off the same system, load management or a larger unit becomes necessary; we break down the exact numbers in our pool equipment and AC sizing guide.
Don't Oversize Out of Caution
The instinct to “just get the bigger one to be safe” usually costs $2,000–$4,000 more than necessary. An accurate load calculation from an actual site visit — checking your panel, your AC tonnage, and what you want covered — gets you the right size the first time. See our cost breakdown by system size for what each tier typically runs installed.
Get an Exact Sizing Number
We'll do a free on-site load calculation — checking your panel, AC tonnage, and square footage — and tell you the exact size that fits your home, not the size that's easiest to sell. This is part of every whole-home standby installation quote. We serve Henderson and the Las Vegas Valley, including North Las Vegas and Boulder City.