TradesHow this works
Pick the loads you want to keep running. The tool adds their running watts, then adds the single largest starting surge, because only one motor spins up at a time. It then recommends a generator size three ways: essential circuits only, the whole house at once, and the whole house on a smaller unit with automatic load management. The wattages are typical starting points you should confirm against your own equipment.
The load-managed option is usually the value pick. It gives near whole-house coverage on a smaller, cheaper generator by shedding non-critical loads for a moment when a big motor starts.
Common questions
Do I add up every appliance surge?
No. You add the running watts of everything that runs together, then add only the single largest starting surge on top. Only one motor is assumed to start at a time, so surges are not all stacked. That is why the number is smaller than a naive total.
What is load management and why does it save money?
A smart transfer switch sheds non-critical loads for a moment when a big motor starts, so the generator never sees every peak at once. It lets you cover the whole house on a noticeably smaller and cheaper unit than powering everything simultaneously.
Can I just plug the generator into an outlet?
No. Backfeeding a panel through an outlet is dangerous and illegal, and can kill a lineworker. A generator must connect through a proper transfer switch or an interlock kit installed by a licensed electrician.
Sources: Generator sizing method (running total + single largest starting surge); typical appliance wattage charts. Engine version 1.0.0. Risk tier 2.