My Air Return Plenum is located in my garage, so insulation is required. The Ductboard(?) box is 33 years old and is cracking and generally not in great shape. The plywood panel under the Air Handler is also in bad condition, although the 2x4 framing is fine. Gravity is forcing me to remove the entire Air Handler unit to replace the Air Return.
I'm in Orlando, FL, so mold is a definite concern as I am allergic to it. I'm thinking of constructing a galvanized steel box as a plenum, and lining it inside and out with Reflectix (bubble-wrap) insulation. Can anyone with experience in this area suggest the best material available?
Thanks!
I'm not experienced with Florida conditions, but it sounds like hot and cold may be causing condensation and rotting out the metal duct work.
I would avoid using more metal and look at duct board for the return air. Insulate around where the hot outdoor air may be meeting any of the cold air-conditioned ducts and that should help.
https://www.homedepot.com/p/Master-Flow-20-in-x-20-in-Duct-board-Return-Air-Box-DRAB20X20/203613224
A UV bulb will help kill any mold and they are easy to install.
https://www.honeywellhome.com/us/en/products/air/uv-air-purifiers/uv2400u5000-u-single-bulb-24v-uv-air-treat-with-airbrightr-odor-absorption-uv2400u5000-u/
Thanks for your response,
Quote from: Admin on December 09, 2022, 05:08:08 PMI'm not experienced with Florida conditions, but it sounds like hot and cold may be causing condensation and rotting out the metal duct work.
Actually, the Metal duct work is just fine. It's the plywood pedestal and the duct board that are falling apart from condensation damage.
Quote from: Admin on December 09, 2022, 05:08:08 PMI would avoid using more metal and look at duct board for the return air.
Since the duct board and wood failed, and the metal is still good, I'm wondering why I should avoid metal.
Quote from: Admin on December 09, 2022, 05:08:08 PMA UV bulb will help kill any mold and they are easy to install.
Excellent idea! Located inside the Return Air Plenum?
I misunderstood, use metal if you can. What's leaking water? The AC coil or just condensation?
Quote from: Admin on December 09, 2022, 10:50:41 PMI misunderstood, use metal if you can. What's leaking water? The AC coil or just condensation?
It's a condensation problem. presumably because the system does not have a P-trap. I'm considering a waterless trap, as at least in theory it doesn't have the problems of stagnant water in the trap, evaporation of water in the trap, etc. What do you think of waterless traps?