Furnace Sizing
Selecting the correct furnace capacity ensures efficient heating and comfort. Capacity is measured in BTU per hour.
Mild
35 BTU/ft²
Medium
45 BTU/ft²
Cold
60 BTU/ft²
Last updated: April 13, 2026
Furnace Size Calculator
Based on 3 sources
100 people find this calculator helpful
Table of contents
sq ft
Did we solve your problem today?