Hey folks! I'm in the process of designing my own ventilated litter box that will utilize both mechanical and electrical components, and I'm hoping to get some advice. Originally, my plan was to use a 4" flexible duct to connect to this fan, which has a rating of 72.2 CFM. I've already sorted out the transition between the two sizes, so no worries there! However, I've found that the 4" duct is taking up more space than I expected. What's the smallest duct size I could use instead? I came across some 'field duct sizing charts', but they're a bit confusing for me. Any insight would be greatly appreciated!
3 Answers
I can't help you directly, but I’m super curious about your project! Please make sure to share a video when you finish it. I’d love to see how it turns out!
For a small space like a cat litter box, 72 CFM seems pretty high! A standard 25 sqft bathroom typically only requires about 50 CFM. You might want to check if this fan vents to the outside, as that could change things a bit. Also, I found some bathroom exhaust ducting charts that might help you adjust—just remember that a 4" duct with no elbows can only go about 4 feet at that airflow. If you're planning to use elbows, you'll want to step up to a 5" duct for better performance, especially if your total length will be around 10-12 feet. Hope that helps!