Tankless Geek topic guide

    Electric Tankless Water Heater Electrical Requirements

    Whole-home electric tankless heaters can require multiple dedicated 240 V circuits and substantial service capacity.

    Updated

    Direct answer

    Read the exact model manual for voltage, breaker count, breaker size, conductor size and minimum service requirements. Have a qualified electrician calculate available service and panel capacity before purchase.

    Do not size from kW alone

    Two models with similar output can specify different circuit arrangements. The nameplate and installation manual control.

    Panel capacity

    Open breaker spaces do not prove that the electrical service can support the added continuous load. A load calculation is required.

    Permits and local code

    Electrical permits, conductor rules and disconnect requirements vary by jurisdiction. The local authority having jurisdiction makes the final determination.

    Questions people ask

    Does a 200 A panel guarantee enough capacity?

    No. Existing household loads and the exact heater input must be included in a load calculation.