We have an exhaust fan in our bathroom that turns on, but it barely pulls any air - after a shower the mirror stays fogged up for hours. Could the grille or ductwork be clogged somewhere? How can I clean it myself and should I call a professional?
Weak ventilation usually comes down to three things: the outlet grille is clogged, the duct is blocked, or the fan itself has lost power. Start with the simplest check - look at the grille from inside the bathroom and from the roof or exterior wall. If you see dust, cobwebs, dried buildup - that's your culprit. You can remove the grille and rinse it under water with a cloth, just make sure to dry it completely before putting it back.
Next, check if you can access the duct. If it's flexible hose or plastic pipe, try removing it and cleaning it from the inside: run a cloth on a stick through it or use a brush. With flexible hose you can even vacuum it with reverse suction. If the duct is built into the wall, that's trickier - you'd either have to remove part of the trim or call a professional.
One more thing: check if the fan itself is actually working. Turn it on and hold a piece of paper up to the grille - if it doesn't get pulled in at all, then the motor's the problem. In that case you either need a pro or a complete fan replacement. But if it's just blockages, you can clear it in about fifteen minutes without calling anyone.
I had a similar situation at home - the exhaust fan was humming, but it barely worked, and the mirror would fog up completely after a bath and stay that way all day. Turned out it wasn't just one problem, but several layers of dirt. I started by removing the decorative grille in the bathroom and found about a centimeter of dust and hair buildup behind it. That was the first barrier.
But even after cleaning the grille, the effect was still weak. I had to get someone to check the main ductwork from outside - turns out it was clogged with snow or bird down halfway through. At that point I needed to call a specialist, since not everyone has access to the shaft on the roof or in the attic. If you have a hatch in your ceiling, you can shine a flashlight in there and see if there are any obvious blockages in the initial section of the ductwork.
Third thing - the exhaust fan itself can get clogged from the inside or just wear out. If you've cleaned the grille and the main duct looks relatively clear, but air still barely comes through, try turning on the exhaust and closing the bathroom door - if the power noticeably increases, then the problem is that air can't get into the room properly. You can fix that by leaving a gap under the door or installing a grille for return airflow.
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