Radiant Floor Heating Calculator

Design hydronic radiant floor heating systems with proper loop sizing.

Room Information

Floor Construction

Tubing Design

Water Temperatures

Loop Constraints

Radiant Output Table

Floor TempRoom 65FRoom 70FRoom 72F
80F30 BTU20 BTU16 BTU
85F40 BTU30 BTU26 BTU
90F50 BTU40 BTU36 BTU
95F60 BTU50 BTU46 BTU

BTU/hr per sq ft output

Design Guidelines

Max Floor Temp: 85F occupied, 90F unoccupied

Typical Spacing: 9" for most applications

Max Loop: 300ft for 1/2", 400ft for 5/8"

Flow: 0.5-1.5 GPM per loop typical