venting/air flow large master bath with high ceilings

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nick evets
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venting/air flow large master bath with high ceilings

Post by nick evets » Mon Apr 15, 2019 3:49 pm

We have a large master bath in a 30 year-old suburban home. The bathroom as very high ceilings -- ~20' -- and ceiling fan and two skylights. There is a toilet closet in the bathroom with a small exhaust in the ceiling, but otherwise no venting except the HVAC supply vents in the floor.

We've had mold issues in the shower stall and paint/sheetrock damage in the skylight boxes from the humidity. Anyone have experience retrofitting some sort of exhaust or wall ac unit in a bathroom like this? Two of the walls are exterior, and there's one window, but it's a single piece of fixed glass.

I know some companies make a recessed light/vent but I'm not sure how to handle the ducting. I've called a few HVAC contractors but none seem interested in the job. :annoyed

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tyrion
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Re: venting/air flow large master bath with high ceilings

Post by tyrion » Mon Apr 15, 2019 4:06 pm

They make wall mounted exhaust fans that duct to the outside. You would need to have electrical run to it. Maybe it could be placed near existing outlets.

Or you could replace the toilet closet exhaust fan with something a little more powerful and put it on a timer. That and the ceiling fan circulating air should do the trick, I would think.

Maybe inquire with an electrician instead of HVAC contractors? I think electricians install bathroom exhaust fans.

I live in southern California, so exhausting moist error draws in dry air. If you live somewhere muggy you probably need to look at HVAC-type solutions.

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lthenderson
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Re: venting/air flow large master bath with high ceilings

Post by lthenderson » Tue Apr 16, 2019 7:54 am

nick evets wrote:
Mon Apr 15, 2019 3:49 pm
bathroom with a small exhaust in the ceiling,
The standard off the shelf ceiling mounted exhaust systems are pathetic in my opinion. Every house I have bought, I immediately remove the blower out of them and put the decorative grate/light back in place. Then in the attic, I install an inline exhaust fan that has three or four times the exhaust capacity and because they are in the attic, make virtually no noise in the bathroom. I can take a long steamy hot shower and the mirror won't even fog up.

livesoft
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Re: venting/air flow large master bath with high ceilings

Post by livesoft » Tue Apr 16, 2019 8:13 am

Put a spare bedroom above a new 8 ft ceiling in the bathroom. Then you will have venting options.

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megabad
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Re: venting/air flow large master bath with high ceilings

Post by megabad » Tue Apr 16, 2019 10:12 am

nick evets wrote:
Mon Apr 15, 2019 3:49 pm
We have a large master bath in a 30 year-old suburban home. The bathroom as very high ceilings -- ~20' -- and ceiling fan and two skylights. There is a toilet closet in the bathroom with a small exhaust in the ceiling, but otherwise no venting except the HVAC supply vents in the floor.

We've had mold issues in the shower stall and paint/sheetrock damage in the skylight boxes from the humidity. Anyone have experience retrofitting some sort of exhaust or wall ac unit in a bathroom like this? Two of the walls are exterior, and there's one window, but it's a single piece of fixed glass.

I know some companies make a recessed light/vent but I'm not sure how to handle the ducting. I've called a few HVAC contractors but none seem interested in the job. :annoyed
Some methods of improvement, in order of least to most cost:

1) If the problem is worst in summer, turn up your thermostat a few degrees in summer. (actually negative costs!)
2) If the problem is worst in winter, decrease your hot water temperature (take colder showers).
3) Assuming existing ceiling fan is powerful enough and positioned so, reverse flow to dump air across skylights. Leave on as much as possible, but at least before, during, and after showers.
4) Remove skylights
5) Undersize HVAC unit slightly when replacing
6) Add dehumidifier
7) Add larger exhaust system and modify HVAC system to incoporate this. Remember, creating a ton of exhaust in one room increase the load on your HVAC system and may cause other issues.

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