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Basement HVAC - Hot Air Supply

831 Views 7 Replies 5 Participants Last post by  jdm127
We are in the process of finishing our basement and are considering extending the hot air supply to floor level. Currently the hot air supply is in the floor joists terminating above the windows. I would like to extend these to floor level and was wondering if I will run into any moisture/condensation issues if they are run in the exterior walls down to the floor. We live in Calgary Canada, so we do have some cold weather.

The cold air return is currently in the ceiling which we will move to floor level in the center of the basement through a stud wall cavity.

Also wondering about drilling through the I joists and if that will cause any weakness to the floor above? The HVAC person did drill a few large holes through the I joists to run the current hot air lines, just wondering how many large diameter holes the I joists can support.

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Not a good idea to drill large holes in structure. You will have to go under to cross over joists
Leave the supplies in the ceiling, and just run your return low. Also increase the amount of return you have.
Holes can be made in TGI's but there are some limitations as to where they can be.Cant remember them but I think its five feet from the ends and you have to leave certain amount of webbing on top and bottom.I'm sure someone known some more info on this.
you are correct..... holes can be cut...... problem is it's different in every province ....... i can get you the maniotba guidelines ....probably won't help you much.....:(
Thanks for the input.

Just wondering how much cold air return we need. The basement is set up with 6 hot air supply vents and currently one supply return.
As much return as you have supply.
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