Boiler Sizing Calculator

What size boiler do I need?

This tool estimates the boiler output BTU your home needs from square footage, climate zone, and emitter type (baseboard, radiators, or in-floor radiant). Confirm with a heat-loss calculation before purchase.

Frequently asked questions

How do I size a boiler for my house?

Boiler size is driven by your home’s heat loss, which depends on square footage, insulation, and climate. This calculator gives a climate-adjusted starting estimate to confirm with a professional heat-loss calc.