Double Sided Vent for Bedroom and Bathroom

[memphisnate]

I'm about to embark on a full bathroom renovation and trying to determine what we want to do with the current HVAC setup. Right now, the bathroom vent is in a dropdown section above the tub. We'd like to open it up to provide more room visually.

I'm thinking I could open up the other side of the bedroom vent that shares a wall with the bathroom. The house was built in '59 so it's metal rectangular ducting so I could simply cut out the other side and put a register on it. I'd have to also close up the hole on the trunk.

It'll balance the temp between the bedroom and bathroom which isn't an issue to me. It'll allow for some of the steam / smell to migrate into the bedroom possibly which I don't think will be a big deal since we'll have a fan in there as well.

What concerns are there with a double-sided vent that I haven't thought of?


Pic Legend:
Blue: Current Vent Locations
Gray: Dropdown above Tub

 

[75gmck25]

We used to have a shared vent in our bath, and found that it did not provide enough airflow to fight summer humidity after showers. I ended up leaving it shared, but upsized the main feed from the plenum to the Y box with one 2" larger, and replaced the vent sections before and after the Y with insulated metal vent instead of the original flexible tubing. The increased size and better flow of the metal vent helped the air flow quite a bit.

Bruce

 

[memphisnate]

We used to have a shared vent in our bath, and found that it did not provide enough airflow to fight summer humidity after showers. I ended up leaving it shared, but upsized the main feed from the plenum to the Y box with one 2" larger, and replaced the vent sections before and after the Y with insulated metal vent instead of the original flexible tubing. The increased size and better flow of the metal vent helped the air flow quite a bit.

Bruce

Good feedback! I need to look in the attic how these 2 vents are currently configured to see potential impacts like you describe. On the good side, it's all solid wall tubing (no flex).

 

[tapered-pin]

I only exhaust the bathrooms to create a negative pressure zone.

Ancillary space like a bathroom doesn't need a supply in my opinion. The rooms are often enough small in comparison to the rest of the house and have such a high humidity environment that I'd rather not inadvertently push that humidity throughout the house.

i want the ambient conditioned air from the adjacent bedroom/hallway to flow into the bathroom and get exhausted out of the house (carrying with it smells from the toilet and steam from the shower - i dont want either of those flowing into the common areas or bedrooms of the house which could easily happen if a supply were in the bathroom)

 

[ripperd]

I only exhaust the bathrooms to create a negative pressure zone.

Ancillary space like a bathroom doesn't need a supply in my opinion. The rooms are often enough small in comparison to the rest of the house and have such a high humidity environment that I'd rather not inadvertently push that humidity throughout the house.

i want the ambient conditioned air from the adjacent bedroom/hallway to flow into the bathroom and get exhausted out of the house (carrying with it smells from the toilet and steam from the shower - i dont want either of those flowing into the common areas or bedrooms of the house which could easily happen if a supply were in the bathroom)

That only works in a bathroom with no exterior walls or a home in a moderate climate. At -20F, a bathroom with an exterior wall NEEDS a heat vent or that toilet seat is going to be really chilly.

 

[tapered-pin]

That only works in a bathroom with no exterior walls or a home in a moderate climate. At -20F, a bathroom with an exterior wall NEEDS a heat vent or that toilet seat is going to be really chilly.

Memphis TN is considered a moderate climate.

 

[ripperd]

Memphis TN is considered a moderate climate.

True enough, although someone looking at your advice from a northern area of the country could be lead astray.

 

[75gmck25]

The house I mentioned in my previous post was in San Antonio, with the bath located on an exterior corner of the house, and that part of Texas is definitely not very cold in winter. However, I don't think my wife would have ever put up with not having a heat and A/C vent in the master bathroom. And if I expected the vent fan to remove all the humidity after showering during the summer I probably would have needed to upsize the vent fan CFM.

Bruce

 

[tapered-pin]

True enough, although someone looking at your advice from a northern area of the country could be lead astray.

True enough, but I was addressing the question as asked by the OP, not some fool who may read the recommendation and think it would apply to their situation in Green Bay or upstate NY.

People correct me all the time on here for practices readily applied across the southeast. Just because they've been a union electrician since the 1980s in Chicago doesn't mean they know a damn thing about how homes are built in the Southeast.

I'm just sayin'