New duct to basement for a/c only

Old 06-22-05, 07:33 PM
Visiting Guest
Posts: n/a
New duct to basement for a/c only

I have a basement that I need to cool in the peak summer months here in Boston. It's usually fine, but I just put in a home theater on the finished side of the basement (about 300 sq. feet), and with the projector and components in the room, along with an audience's collective CO2 exhaling, on a very humid and warm day, it gets a bit uncomfortable and fans alone are just not cutting the mustard.

My plan is to head up to the attic where my air handler/trunk is, and tap a new run off the side of the air handler (all other zones, to 2nd and 1st floors only---none originally run to the basement). I have thus far bought a starter collar, 25 feet of 6" flex duct, a 'T', 2 12x4 registers, and 2 12x4 diffusers. I am going down pretty much in a straight line (through a 2nd floor closet and a 1st floor pantry), to get the duct to the drop ceiling tile location where I'd like to 'T' it off to the 2 separate diffusers, which will be on either side of the projector, and look nice and symmetrical (okay, so aesthetics plays a small role here, too---isn't it okay to branch off short 'T'd runs like that)?

From reading several related posts, I have an idea on things, but for clarification, 1) How do I tap into that trunk 'successfully'---can exact steps be listed? and 2) How to go about correctly 'sealing' the duct to the 'T' and to the diffusers and, of course, to the trunk itself once I cut the 6" hole and insert the starter ring?

I don't plan on installing a return duct, as the staircase just adjacent to the 'theater' leads to the 1st floor area and that door is ALWAYS open, and there's a door over to the unfinished side of the basement that is likewise always open. I currently use a portable dehumidifier and a fan to 'manage' the comfort levels in the room in the summer months. In winter, when I 'need' heat down there (not often), I already have 2 electric baseboard heaters installed (from previous owner).

Thanks to Ed and any others for their thoughtful replies/responses!

Old 06-23-05, 09:03 AM
Ed Imeduc's Avatar
Join Date: Aug 2002
Location: Mountain Williams Missouri
Posts: 18,386
Received 0 Votes on 0 Posts

That 6 " pipe cant give you the cfm you need for 2 registers there.Its only 100 cfm is all. Just one outlet .

Cut and put that starter collar in the duct. pull some liner out of the flex pipe slip it on the collar and band it. then pull the insulation over that and band it to the collar then seal the edge of the flex pipe to the duct with a duct sealant.


Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: