My house is a ranch with the air handler in the attic which in summer gets extremely hot and humid. I noticed last year at the end of the season that my supply plenum is wrapped in like a Reflectix type of insulation and the bottom of it was sagging. That's when I realized that it had collected condensation (quite a bit of water) between the metal air handler plenum and the Reflectix type of insulation. Are the air handler/plenums in the attic supposed to be wrapped in insulation? And if they are is there a way to prevent condensation build up between the two? I worry water could make its way into the system and grow mold.
NYhomeowner
If no insulation then it will sweat like crazy. That insulation probably to tin. Need thicker insulation. Wrap more or pull off everything and spray foam in
To explore your issue further (NEVER put an AC in the attic - only at last possible option) Would you want to be the guy to work on it when it is 100* outside, the attic is 130° / 90% RH?
The AC normally pushes out around around 45° air. Your attic is hot and the RH (Relative Humidity) is high, so the duct work will condense that air and the water will drop out. Kind of why when you take a milk jug out of the refrigerator and water collects on it, the water in the air drops out. This is called Dew Point. The last time I personally installed one in an attic, I used 1" armaflex sheet insulation on the inside of an over sized sheet metal supply trunk then to insulated flex piping to the registers. This has down falls, as the insulation inside not only can collect dust and dirt, but slows down the air flow as it is not smooth and resists the air flow, thus why I over sized it, slowing down the FPM (feet per Minute). In your case, someone decided to just wrap it around the outside of the duct, which never lasts very long. Best answer is find 3/4" or 1" Armaflex sheets (comes in 3'x4') and Armaflex glue (contact cement), rip off all the old and re-insulate. If you want to wrap it with fiberglass insulation, it WILL fall off again, no mater how hard you try to keep it on there. Compressing that fiberglass with support reduces the R value greatly, and you are back to square one.Spray foam makes a huge mess, no mater how good you are. IT is not consistent, and will not stay on the sides or bottom when you spray it. Either way, you need to find a way to prevent attic air from hitting the sheet metal. If you don't. you are asking for big troubles like you suggested - MOLD.
Good Luck
The AC normally pushes out around around 45° air. Your attic is hot and the RH (Relative Humidity) is high, so the duct work will condense that air and the water will drop out. Kind of why when you take a milk jug out of the refrigerator and water collects on it, the water in the air drops out. This is called Dew Point. The last time I personally installed one in an attic, I used 1" armaflex sheet insulation on the inside of an over sized sheet metal supply trunk then to insulated flex piping to the registers. This has down falls, as the insulation inside not only can collect dust and dirt, but slows down the air flow as it is not smooth and resists the air flow, thus why I over sized it, slowing down the FPM (feet per Minute). In your case, someone decided to just wrap it around the outside of the duct, which never lasts very long. Best answer is find 3/4" or 1" Armaflex sheets (comes in 3'x4') and Armaflex glue (contact cement), rip off all the old and re-insulate. If you want to wrap it with fiberglass insulation, it WILL fall off again, no mater how hard you try to keep it on there. Compressing that fiberglass with support reduces the R value greatly, and you are back to square one.Spray foam makes a huge mess, no mater how good you are. IT is not consistent, and will not stay on the sides or bottom when you spray it. Either way, you need to find a way to prevent attic air from hitting the sheet metal. If you don't. you are asking for big troubles like you suggested - MOLD.
Good Luck
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