High humidity in bathroom
#1
08-25-22, 08:38 PM
Join Date: Oct 2012
Location: USA
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High humidity in bathroom
Sorry this might not be the right section for this but I am trying to understand why my guest bathroom can fluctuate so much in humidity, even in the evening. I recently added a small dehumidifier which seems to help, and def collecting some water (not a lot though). I have an external humidity sensor and it will range from 45% to 55%. When it hits over 50% it is noticable as you walk into the bathroom that the air feels much warmer. I will add I live in south FL, and its summer, so definitely hot outside.
At first I was thinking it was the cabana door I have however I used a smoke machine and dont see any leaks. I checked the AC vent in the room and appears to have cold air coming out. Only other thing I can think of is the exhaust vent that goes to my roof. Perhaps better to post on an area regarding bathrooms but I wonder if when the fan isnt running if it just allows all the hot humid air to come right back into the vent? I dont see a flap/check valve type system (does this even exist for exhaust vents on the roof?) so maybe thats worth looking into.
FWIW I dont recall it being this humid in there but until a couple weeks ago I never really thought about it, or checked the humidity % so hard to say if its been this way for the last 10years Ive lived and I only now took more of a notice. Anyhow, any feedback is appreciated!
At first I was thinking it was the cabana door I have however I used a smoke machine and dont see any leaks. I checked the AC vent in the room and appears to have cold air coming out. Only other thing I can think of is the exhaust vent that goes to my roof. Perhaps better to post on an area regarding bathrooms but I wonder if when the fan isnt running if it just allows all the hot humid air to come right back into the vent? I dont see a flap/check valve type system (does this even exist for exhaust vents on the roof?) so maybe thats worth looking into.
FWIW I dont recall it being this humid in there but until a couple weeks ago I never really thought about it, or checked the humidity % so hard to say if its been this way for the last 10years Ive lived and I only now took more of a notice. Anyhow, any feedback is appreciated!
#2
08-25-22, 08:40 PM
Join Date: Oct 2012
Location: USA
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Also to add the exhaust fan I have now is def nothing special. In fact its likely the unit that came with the house (20years ago). Its a NuTone 672RB 4.0 sones 110cfm. I'm thinking its time for an upgrade regardless but wanted to mention. Thanks again
#3
08-26-22, 01:13 AM
Group Moderator
Assuming that the shower is not the source of the excessive humidity leaves air leakage from outside into the bathroom. Is the bathroom on an outside wall ? Is that wall hot ?
An A/C register in that room is good and that would require the door to be left open when not in use to draw air out of the bathroom. You can't blow air into a room without it also being drawn out.
An A/C register in that room is good and that would require the door to be left open when not in use to draw air out of the bathroom. You can't blow air into a room without it also being drawn out.
#5
08-27-22, 06:43 PM
Forum Topic Moderator
I usually install a 4 inch backdraft damper in a vertical section of the bathroom exhaust duct.
I usually only need the $15 damper, a pocket knife, and duct tape.
Amazon has them.
I usually only need the $15 damper, a pocket knife, and duct tape.
Amazon has them.
