Rustic Exposed Ductwork Design Barndominium

Job ID: 39186778

Budget: $30 – $250 USD

I am looking for help in designing an A/C system (in floor heat) for the front room (24x40X18) of a barndominium that I have built. I live in Cedar Rapids Iowa. It has 18" blown in in the attic, 3 exterior walls of 2" closed cell foam, and a dividing wall with the shop having 6" batt insulation.

I believe that I need 4 tons of cooling and would like to use a packaged unit sitting outside. Both the return and supply would go vertically on the outside of the building (exposed) and then horizontally across the room. The return air would terminate at the wall. The filter woudl need to be at ground level on the return.

I would like to hang round spiral ductwork inside. I would like to have 3-4 registers pointed "down" and 3 registers pointed horizontally to the loft. I am in hopes that we will not need any trunk lines. I woudl also like to add electric dampers to the ducts pointed down so that they can be partially closed, forcing more cool air onto the loft if we are sleeping up there.

I do have 2 DC ceiling fans mounted down 36" from the ceiling centered in the front open part of the space. I will be running these 24/7/365 to keep the air better mixed.

These are my basic preferences but could be open to ideas. I woudl like for it to be simple as far as design and installation. The attached drawing are just my thoughts and may or may not work. Thanks!