enter image description hereSo I have a 1.5 car garage that seems to be sealed off, airflow wise pretty well. Any moisture from rain or snow just seems to sit and not evaporate at all or extremely slowly. Also, I dry out my hockey equipment in there and I'd like a way to vent the smell and moisture if possible.

I was able to purchase a 100CFM multi-port in-line fan, which allows for four 4" vent/port lines to attach to it. I plan on using 3 of the lines and using 4" plastic diffusers in the ceiling to vent the garage space. I will bring in fresh air into the garage via a decorative shutter that was placed on the exterior wall where I can place a shutter vent behind it. The 4" diffusers are said to cover 60 sq ft. although I'm not so concerned with the proper measurements, just looking for an inexpensive way to vent the garage better. I'll be installing an hourly timer switch in the wall so it will run for 2-4 hours then shut off.

I've outlined the general layout of the garage and where I'll be placing the vents in the ceiling. I just want to make sure I'll be placing the vents in the most optimal location to take advantage of the ventilation. I came up with a crude schematic and images of the fan and vents to give you an idea. Not sure if I should use the 4th port/vent in the fan or not with the setup I'm doing.

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You probably don't need to add the fourth vent. If the fan is rated for 100cfm then 4 inlets will pull roughly 25cfm, 3 about 33cfm and so on. As long as the ducting for the 3 vents are of sufficient size and length to handle 33 cfm it should be just fine. I don't have my chart with me at the moment but a 4" pipe pulling 33 cfm should be good up to 25'. A larger outlet pipe will cut back on noise.

  • How far should I space the diffusers from the wall? Ideally, I want to put a vent louver / fan shutter as an intake so the vents/flap will close when not drawing air in. I was thinking about a 4" diameter vent/shutter, but I know they make 6" as well. Any advice as to what would be good or work well? Thanks Commented Mar 30, 2019 at 21:48

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