I know I have read about this here but I can't find the thread anymore. I have a 4" duct in my window and light is reflecting out of it. Is there some way to block the light and not the airflow? Any advice would be appreciated.
If you rely on bent ducting for light proofing try to get as much black paint inside as possible. Or wrap up the whole S in something black. Make the bends as smooth as possible for the space you have, avoid sharp "switchback" corners. More convenient and robust if you have the space and don't need to hide it would be qty-2 4" ABS pipe elbows 90degrees, connected to each other, maybe $5-6ea at the big hime sores. ABS better thjan PVC ecause its black, which is what you want anyway. if you need to hide it, it can be done as well. If you use small fans the plubming also provides a good anchor point, you may be able to improve your circulation with minimal additiaonal efforrtttttttttttt so stoneddd Another option if you're short on space is a shallow baffled box i don't know exactly what it would look like but im sure you can imagine inside a lot of like overlapping channels n shit, they make huge ones for commerical application like this http://www.acmeag.com/pdfs/B158.PDF