FAN SIZING FOR
BATHS OVER 100 SQ. FT.
Ventilation for baths over 100 square feet is calculated based on the
fixtures in the bath.
Allow 50 CFM for each standard toilet, shower or tub. Whirlpool and
jetted tubs are calculated
at 100 CFM. Add up the CFMs for all fixtures and you'll have the total
11' x 14' Bath = 154 square feet
1 Toilet + 1 Shower + 1 Tub = 150 CFM
1 Toilet 50 CFM
1 Shower 50 CFM
1 Tub 50 CFM
Total 150 CFM
YOU WILL NEED A 150 CFM FAN.
Fantech recommends that steam showers use a separate fan on a timer so
that the fan
may be shut off during shower use and then run afterward to dry the
For proper airflow in typical installations (when duct losses aren’t
use the 0.4”Ps (static pressure) rating point for correct fan selection.