Power
By the calculated load + reserve: house 5 kW calculated → 7-8 kW generator. Starting currents of the pump/fridge: ×2-3 for the moment.
Type
Gas — quiet, cheap fuel; diesel — powerful, for long work; inverter — clean sine for electronics.
ATS
Automatic start on outage, warm-up, transfer, cooldown stop. Manual transfer is cheaper but requires presence.
Installation
Outside, under a canopy: exhaust away from the windows, grounding, fuel reserve, soundproofing (from 40 dB).
Connection
From the generator — a cable of the right section to the ATS; no sockets in the house from the generator without a switch.
Why design
The design counts the power and the switching — the generator works when needed.