Sizing an Automatic Transfer Switch to Your Home
Last verified: September 2026
How a transfer switch is sized to match your service and your generator — and why you don't have to do a lick of the math. Rather have a hand getting ready? My number is (330) 200-8042.
Sizing a Transfer Switch, at a Glance
A transfer switch is sized to match two things — your home's electrical service and your generator — so it can carry your must-run list, including the big starting surge that motors like the well pump need. Whole-home coverage needs a bigger system; a managed setup lets a smaller one cover the same home. Best of all, the math is your electrician's job — you just bring the list. There's a printable 29-page version up top.
Common Questions
1 What size transfer switch do I need?
The one matched to your electrical service and your generator, sized to your must-run list. Your electrician reads your service's rating off your panel and does the math — you bring the list.
2 Why does the starting surge matter?
Motors — fridge, furnace, well pump — briefly need several times their running power to start. A system sized only for steady running may not start them, so sizing accounts for that surge.
3 Can a smaller generator cover my whole home?
Often, yes — with load management, which lets the biggest appliances take turns. Ask your electrician to size it both ways; the savings can be real.
4 Do I need to know my home's amp rating?
No. Your electrician reads it right off your panel. You don't need to hunt for numbers — just bring your must-run list.
5 Is a bigger system safer?
Not really. An oversized generator costs more, burns more fuel, and isn't ideal running lightly loaded. Right-sized, with a sensible cushion, is the goal.
6 How do I get an accurate quote?
Bring your must-run list, note whether you're on a well, have any generator's information handy, and let the electrician see your panel in person. Good information makes an accurate size.
Would You Rather I Just Help?
Sizing is the electrician's math, but getting you ready for an accurate quote is exactly what I help with — your must-run list, your panel photos, and a trustworthy pro. $99 flat for a visit, 30-day come-back-free.
Would you rather I just do this for you?
No shame in it — plenty of folks would rather hand it off, and that's what I'm here for. I'll come to your home, set it up right, and make sure it's working before I leave. Flat $99 per visit — no jargon, no upsell, and every visit is 30-day come-back-free.
Not a hardware job? I can often fix it remotely for $49 — a secure screen-share, up to 2 hours, that you watch the whole time and can end whenever (included free for $39/mo Support Plan members, and it counts toward the $99 if it turns out I need to come out).