Too much Condensation on Bathroom Walls With Shower

TonySakFebruary 15, 2012

Sorry im not sure which forum is best.

Hi All,

So we have a new construction house. In our master bathroom

we have a 150cfm Panasonic main fan for the shower, and a Panasonic 80cfm fan for the separate toilet room.

When we shower a TON of condensation forms on the plaster walls. We have never seen it before. Basically the paint job is ruined. I can't figure out how to fix it. Its not the air flow, we have tired one or both fans with the door open and shut and there is a ton of air moment. The heat is on when we shower so the walls are room temp. The mirrors also do not really fog up.

Any ideas?

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Do you turn on the fans before you start your shower? Is the problem with an exterior wall? Are the walls really made of plaster or is it sheet rock?

    Bookmark   February 15, 2012 at 4:54PM
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Yes we do. I let them run for 5 min to kinda try to get things going. The condensation is uniformly across all the walls (interior and exterior). All the walls are also warm and the heat is on.

we do actually have plaster.

The main vent has a 6" duct. With both fans on you can really feel wind resistance when you shut the bathroom door. so there is a lot of air moving. I just don't get why everything isn't sucking up.

A 150 cfm main fan and another 80 CFM fan should be plenty of power right?

    Bookmark   February 15, 2012 at 7:36PM
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Two fans with 230CFM of air movement is a lot of air. This would be sufficient for a big bathroom. Are you taking very hot and long showers? Does your bathroom have a steam system?

Some moisture on the walls is unavoidable. Do the walls have builder's grade flat paint? You may need to repaint using a qualtiy paint with some gloss.

    Bookmark   February 16, 2012 at 9:35AM
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no the total air moment is 230 CFM. I fan is 150 cfm the other is 80cfm. The room is 10x10x8 The paint is the Ben Moore Bathroom Paint at $60/gal, its eggshell.

Showers are average 20min, and it wouldn't be a shower if it was hot. No steam units or anything yet. Here are some pictures. Any other ideas?

    Bookmark   February 16, 2012 at 12:17PM
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What are the relative humidity and temperature in the rest of the house and outside when you have these problems? It seems unlikely, but if the air in the house is near the dew point, diluting the air in the bath with that won't help much.

    Bookmark   February 16, 2012 at 2:24PM
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When I built may renovated my bathrooms I put the fans (Panasonic 150CFM) inside the shower stall. Where are you fans releative to your shower?

As an experiment take a shower with the bathroom door open. You may not have enough air intake for your exhaust fan.

    Bookmark   February 16, 2012 at 3:25PM
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The door doesn't need to be fully open, just open a few inches for air to pass in.

    Bookmark   February 17, 2012 at 3:54PM
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