We have had issues getting mold/mildew in 2 small coat/towel closets due to having tall 10 foot ceilings (I think that is the issue). Towel closet is next to a bathroom but opens up to the hall with a return vent in the ceiling. As I was cleaning and repainting the closet ceilings I noticed how much hotter and more humid the top of the closet is, which I assume is due to lack of air movement.

We have our AC company coming today, but what are my best options to get air moving through those closets to keep the heat/humidity down? The closet doors have already been trimmed at the bottom to increase air flow. We have had AC issues/ mold since we built the home, but it has mostly been corrected except for these problem spots.

Return air vent in the closet?
Ac vent in the closet?

Insulation above closet? water leak behind closet wall? I would not put a vent or return in a closet, unless it is big.

Plenty of insulation and no water leaks. It not a water leak mold infestation, but just a surface humidity type of mold, if that makes sense. I can easily wipe it off with a paper towel.

SWLAg said:

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We have had issues getting mold/mildew in 2 small coat/towel closets due to having tall 10 foot ceilings (I think that is the issue). Towel closet is next to a bathroom but opens up to the hall with a return vent in the ceiling. As I was cleaning and repainting the closet ceilings I noticed how much hotter and more humid the top of the closet is, which I assume is due to lack of air movement.

We have our AC company coming today, but what are my best options to get air moving through those closets to keep the heat/humidity down? The closet doors have already been trimmed at the bottom to increase air flow. We have had AC issues/ mold since we built the home, but it has mostly been corrected except for these problem spots.

Return air vent in the closet?
Ac vent in the closet?

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I'd say to get the most air moving a bathroom fan on a timer or rigged up to a hygrometer to turn on when the humidity gets above a certain %.

A vent above the door with the trimmed doors may initiate some air movement but I'm not sure how much you'd get without a motorized fan.

AC vent - I'm not sure how that would work in a towel closet.

We put an AC vent in a closet when we put in home networking equipment.

If you have a 1 story house, I'd put in a vent and be done.

Piggy backing off this post:

I am dealing with this same thing right now. Had 4 closets with surface mold. My wife insisted we have the ceilings cut out and replaced. But the underlying issue is still there.

First it started with 75-80% humidity in the closets. I found what I thought was the source of a clogged AC condensate line in the wall sweating and putting a ton of moisture in the walls.

I cut that line and re-ran it to the emergency drain line straight out of the house for now. Had AC company check it out and they say the unit is working fine.

Now two weeks later I have 75-80% humidity in the entire house at some points throughout the day.

I have been in the attic to check for leaks 72 times this past week and nothing. No known leaks, no water damage throughout the house.

I am dumbfounded on what to do next....

I'm by no means an expert but have paid thousands chasing our problems down, this is just the last of it. How often is the AC running?

Most of the day

We've had a dehumidifier installed but it makes our fan run all the time and actually increases our humidity. Once we turned it off and put the AC back on "auto" that helped. Something about the fan constantly running wont let the air slow down and dry out.

SWLAg said:

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We've had a dehumidifier installed but it makes our fan run all the time and actually increases our humidity. Once we turned it off and put the AC back on "auto" that helped. Something about the fan constantly running wont let the air slow down and dry out.

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Do you need a newer AC?

We had a 30 year old unit and it could not handle heat or humidity. When we got a new dual stage installed, it will run in the background to lower the humidity even if it is not cooling.

No it's a brand new house and the AC company was a bunch of idiots. We just had a different company run all new duct work with a correct sized plenum and it's running much better, keeping electricity bill low as well.

Humidity is now staying in the mid 50s, but if the fan is set to "on" it will go up quick. We are definitely pushing the the limit to where we really needed 2 units as well.