New to me home, built in '87 and it turns out, a lot of lazy work/ cut corners. Vents aren't sealed anywhere, doors are warped, window frames are ...struggling. We'll be placing a lot come spring, but right now, everything is frozen and with wind chills in the -20s+ we're not able to do much work on these areas. All this to say, the venting through the house will no doubt show similar issues - I just took the vent fan cover down (probably original to '87) in the powder room to take a peek, and it's so packed full of grey dust/material that there's no way it's doing anything - two questions: do we need this fan at all? I can't find that it's needed by code (small powder room, no shower/bath) and the home has humidity control. If we get rid of it can I put a LED light there or just cover it over? I am guessing I'd need to have that duct work sealed off somehow? We have an HVAC guy coming but everyone is booked out a bit right now with severe winter weather and I don't mind getting my hands dirty doing what I can. Fans in every bathroom will need replaced. Next question, if the fans are all like this is this a warning sign of moisture in the duct? Or just years of not cleaning?