Mini Split Size Guide BTU sizing & cost basics

Calculator · contractor-ready

Room BTU sizing calculator

60-second room or multi-zone screen: cooling and heating BTU, snap-to-stock head classes, and a Good / Better / Best shortlist. Educational — not a Manual J.

Contractor mode off

Plan type

Sun exposure
Insulation / envelope
Ceiling height
Windows

How to use the result

  • Use it to set expectations at the kitchen table — then run a Manual J (or equivalent) before ordering
  • Confirm low-temperature heating capacity in cold climates (zone 5+)
  • Match indoor head location to airflow, not just wall space
  • Check multi-zone combinations on the manufacturer’s selection tool

Oversizing can short-cycle and hurt humidity control; undersizing struggles on peak days. The right answer is a real load calc, not a rule of thumb alone.