Instlaling Ductwork in Existing Home

Old 10-23-16, 03:22 PM
Thread Starter
Join Date: Jul 2016
Location: USA
Posts: 23
Upvotes: 0
Received 0 Upvotes on 0 Posts
Instlaling Ductwork in Existing Home

I'm a recent, first time homeowner. My home currently has a very unorthodox method of ductwork. The original HVAC install just dropped the ceiling by about a foot in the main hallway, encapsulated it in drywall, ran one central line off the unit and fed it into the drywall. Each room has a drywall cutout to the hallway with a vent. I've recently found that part of the drywall where the main line enters the home has collapsed and is leaking a good bit out to the attic.

I'm wondering about the feasibility of me running all new ductwork. I've done a manual J calculation for my home using the demo for Right Suite Universal. I planned on using the existing metal supply/return duct (if it's sized appropriately) and using takeoff's of that to run my new lines.

Here is a link to my manual J calcs and home/duct layout proposal.

Currently I have a 4 ton unit. The laundry room has never had central AC and I've currently got a small window unit in there. I plan on adding more insulation over the entire attic area of my home to bring it up to R38 value. When I make that change, I assume it should make it more manageable for the unit to handle the additional sq ft.

Is this a manageable DIY job? I don't plan on getting this done overnight. Thankfully, the weather is just starting to get a little nicer around here (North MS) to where working extended periods in the attic are more manageable.

Old 10-25-16, 05:42 AM
airman.1994's Avatar
Join Date: Dec 2005
Location: VA
Posts: 5,795
Upvotes: 0
Received 8 Upvotes on 8 Posts
It's easily a DIY project. You have already done the most important thing (Heat Load). Find a sheet metal shop that can make your duct and you should be good to go.
Old 11-17-16, 05:27 AM
Join Date: Dec 2011
Location: Usa
Posts: 236
Upvotes: 0
Received 0 Upvotes on 0 Posts
I did my own system. I did a heat load calculation to size my system. I had a company cut the duct board to size, I folded the pieces and taped them all together, and hooked it to the air handler.

I then sized the rooms and ran the correct size duct to the rooms and cut in vents. The I had a hvac tech hook up the wiring and line set and I was good to go. Hardest part was cutting all the holes for the vents.

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