Exhausted

Well, today was no big surprise.  Same old same old.  Homeowner was complaining about mold and mildew growing on the walls and ceilings of their bathroom.  I won't even go into the fact that the ceiling tile in the bathroom was not rated for moist areas (like a bathroom, but they bought it  because it was on sale at Menards a few years ago.  That is a discussion for another day.)

So, the first thing I ask, and check on, is the exhaust fan working?  So, we flick the switch and sure enough the fan is working.  Next I take a closer look and the fan cover has more dust and hair on it than a dirty cat in a desert storm.  So, together we clean the cover, change the burned out light bulb and remove the moldy ceiling tile.  Upon removing the last piece of tile around the fan I notice that someone stole the vent pipe and the vent to the outside. (Ok, being silly here.  Who 'steals' this?)  Unfortunately the do-it-yourself previous homeowner put this in and didn't properly vent the fan to the outside.  Basement fans get exhausted through the floor rim joist and upper floors through the roof or side wall.  This just vented to the joist space.  Upon further investigation of the joist space I found, you guessed it, MORE mildew and mold.  Here is the magic formula for this:  moisture plus warmth plus organic source (like wood, ceiling tile and drywall) equals mold growth.  If you remove any of those from the equation you remove the problem.  The exhaust fan can remove the moisture from the room.

So, I connected a vent pipe to a new through the joist vent and turned on the fan.  The home owner was impressed how fast the odor in the room left.  They thought that the whole fan needed to be replaced because of the mold and mildew issue.  No actually.  Just hooked up.  I showed them that the 60 cu. ft. per minute rated fan they had was plenty for the  five by eight room. 
Length x width x height of room
Then multiply by 8 because bathroom should have 8 air changes per hour.
Then divide by 60 because we went to know how many Cubic Feet Per Minute (CFM) fan we should have.

8ft x 5ft x 8ft =320 cubic feet of room volume
320 x 8 air changes per hour = 2560 cu ft per hour
2560 / 60 minutes per hour=42.67 cfm   so the 60 cfm rated fan they had was plenty of "fan" for the job, it just needed to be hooked up and of course kept clean.  Imagine if you had a hairball in your throat, would you breath very well?

Well, that is all for now.  I hope that something in this little story "Hit Home" with you.