Attic Inlet Capacity = House Width X House Length X 1.5 CFM/SF
# Attic Inlets per House = Attic Inlet Capacity / 1,669 CFM
Placement
Place first and last inlet 20’ from endwall of house.
40’ Wide House
Alternate inlets either side of peak of the house
50’ Wide House
Alternate inlets 2’ – 3’ from the peak of the house.
60’ Wide House
Alternate inlets 6-8’ from the peak of the house
Inlet spacing = (House Length – 40’) / (# Inlets +1)
Example: 500 ft – 40ft = 460 ft
# inlets per house = 12
460 / (12 inlets per house +1) = 35.38ft
Inlet Spacing = 35 ft O.C.
