I can get a better picture if necessary but I was told this main duct is fiberglass and should be replaced. This is the main duct into my AC unit in attic. The HVAC company
said this is the only duct like this the rest they said are ok.

I have been having breathing issues for a while and am trying to get to the bottom of it. We had the ducts cleaned and they suggested that the fan on the AC be hooked up to a Honeywell thermostat to circulate air since I have cold pockets in my house with the baseboard heat. We did that and I feel worse.

My house was built in 1986. Not sure if they have ever been replaced. Been here two years and feel like crap.