I recently moved into an old brick house (slate roof), containing several bathrooms without vents. It's a problem that I've been wanting to correct, though I've put it off because I'm not sure if knocking a hole in either the brick wall or slate roof is worth the hassle (esp. with respect to what I want from the system).
Since the fan's purpose is to move air out to remove humidity and odors, are there any fans out there that push the air through some type of replaceable desiccant to remove moisture, and charcoal to de-odor, so the air could be released back into the attic instead of the outdoors? To me, this seems like a reasonable option, considering I wouldn't have to worry about making holes in my bricks/roof (not to mention it eliminates the possibility of cold outdoor air flowing back in, which I hear is a problem even with dampered vents). Has anyone seen or used any such exhaust fans (do they exist)?
With respect to outdoor venting, the only option I can see, since it's a walk-up attic with small windows on the gable ends, might be to cut a circular opening in the glass that just fit the vent pipe (with damper from the other questions I've read) and finding a way to seal it properly might be an option (which means never opening the window). Is this an acceptable way to go about this?
Any suggestions and best practices for this old house would be appreciated!
Best Answer
Cutting a hole through brick is no big deal. You could use one of these as a disposable hole saw for $20:
Or one of these as the "right" tool, which will be reusable for $75:
Most hole saws require a 1/2 inch drill plus a ~$10 arbor, both of which will be very useful for other projects in the future, like installing door knob sets in new doors, installing plumbing, ductwork, plenums, and all kinds of projects in plywood, sheet metal, lumber, plastics, etc.
When making the hole, take care to slant it slightly downward (2%—1/4 inch per foot—is typical) toward the outside to prevent rain, etc. from finding a path indoors. Install a vent device with a damper to prevent hot/cold air from coming inside when the fan is not on, and seal the hole at the outside surface thoroughly with silicon caulk.
Slate can be cut by this type of blade too, but holes through the roof are often fussier to make leak free.