Plan Your Duct Work To Maximize Attic Space

Most houses built today use common trusses that don’t provide for attic space like older homes framed with traditional rafters. In a recent post, Creating Storage Room With Attic Trusses, I pointed out the benefit of using attic trusses to create inexpensive storage space. In order to take advantage of that newly gained space it’s important to plan your duct work installation with your HVAC contractor.

As you can see in the photos we have a very large attic storage room. Our house is cooled with a high velocity SpacePak central air conditioning mini duct system. Most HVAC contractors would want to lay a central duct down the center of the house and pull the room branches directly off the trunk. I made it a point to discuss with the HVAC contractor the importance of maintaining our new storage rooms floor space. To achieve the space that I wanted he ran a main trunk around the perimeter of the finished space just inside the trusses as you can see. With this layout we were able to keep the entire floor space open for storage.

This layout will cost slightly more for the additional duct work and labor but it’s a small price to pay for preserving the storage space that you already paid to create. As you can see from the photo all of the branch ducts come off the main duct and run to each room individually. After the system was installed we had cellulose insulation blown in to completely fill all the voids.

The other detail that I’d like to point out is the support of the air handler. As you can see in the photo the air handler is supported on a sheet of plywood that is supported from framing that hangs from the trusses. This detail helps minimize vibrations to the ceiling surfaces in the living space. The vibrations are transfered to the roof surface instead of the ceiling below. If you’re having an air handler installed in your attic make sure you discuss these details with your HVAC contractor.