Splitting duct to a new bathroom - DIY Chatroom

nalishaw · 10-30-2009, 06:42 PM

I am drawing up plans to build a bathroom in my basement and am trying to determine how this space should be heated. Currently the basement is unfinished and there is a duct that runs to my upstairs bathroom - which is directly over top of my downstairs bathroom. The duct work is rectangular and the upstairs has a large old style grate cover. Is it possible to split this duct to run heat to both bathrooms? Thanks!

thehvacguy · 10-30-2009, 06:56 PM

It would be possible to split the duct to serve both bathrooms but most likely it will be incorrect. Then the original ducts were sized, the were sized according to the amount of cubic feet in each room. If you tap in to that duct, you will be taking away from the upstairs bathroom and the airflow to the upstairs would be inadequate. If you decide to split the duct, you will have to follow that duct back to the unit and enlarge the duct up to the splitting point.

beenthere · 10-31-2009, 12:09 AM

Guessing the basement bathroom won't be used much.
Use an electric heater.

Splitting the duct like you want. It would not keep the lower bathroom warm.
The cold air from upstairs will fall into the the lower bathroom. And the warm air from the lower bathroom would rise to the upper floor room.

thehvacguy · 10-31-2009, 01:54 PM

That is true, you have a very good point there.

tinmanrob · 10-31-2009, 03:22 PM

Another thing to consider is sound transfer.