Most single-family homes in our area land on an 18–26kW air-cooled generator for true whole-house coverage, or 14kW with smart power management. But the right size depends on real math, not square footage rules of thumb. Here's how professionals size a system.
Start With What Must Run
List your non-negotiables:
- HVAC — the biggest load in a coastal home. A 4-ton AC can demand 5–6kW running and far more at compressor start
- Water heater — electric tank units pull 4.5kW; tankless electric units can pull 18–28kW and often need special planning
- Well pump — critical in rural Horry County; high starting current
- Kitchen — refrigerator, freezer, range
- The rest — lighting, outlets, garage door, internet, security
Running Watts vs. Starting Watts
Motors (AC compressors, well pumps, pool pumps) briefly draw 2–3× their running load at startup. An undersized generator that handles everything running can still stall when the AC kicks on. This is the single most common DIY sizing mistake. And not every generator has the same motor starting power!
The Fuel Factor
Generator output ratings differ by fuel. A "26kW" unit may produce 26kW on propane but only 24kW on natural gas. If you're on natural gas, size against the NG rating — and have your gas meter checked, because standby generators often require a meter upgrade for adequate flow.
Power Management Changes the Math
Modern systems (like Champion's aXis and Briggs & Stratton's Symphony load management modules) can shed low-priority loads automatically — for example, locking out the second AC unit while the oven runs. This lets a smaller, cheaper generator safely cover a larger home. It's how a 14kW unit can protect a home that would otherwise need 22kW.
What About Square Footage?
Square footage is a starting hint, nothing more. A 2,000 sq ft all-electric home with a tankless water heater and a well can need more generator than a 3,500 sq ft home on natural gas with gas appliances. What matters is your actual connected load.
Get Sized Correctly — Free
Our online quote tool walks through your home's square footage, appliance fuel types, and large loads, then recommends a properly sized system with real pricing: palmettopower.net/quotes. Prefer a human? Call 843-466-4488 for a free in-home load evaluation.