I am about to install my first Attic air handler and duct work. I know the duct has to be insulated. Is there a "standard" size to the insulation in R value? I will be using metal ducting. What other precautions should I take with this installation? Any suggestion are welcome. I have done far too many installations of furnace systems but have always stayed away from the attic jobs, leaving them to the younger guys. But this job is for family.
Thanks.