I have flexible ac ducts in the attic. The plastic wrap on the ducts has deteriorated in several places, exposing the bare plastic duct with no insulation (insulation has pulled away from the seams). What is the best type of duct wrap or insulation to replace the bare areas, and is there a particular way the insulation should be applied, for example, foil side out, etc. I live in Texas where the summers are very hot. Thanks.

When you buy ductwrap, it should come with instructions,, but the foil side out,, just cut off the size/amount needed ,wrap around the flexduct and tape it around real good

Sounds to me like it is time to buy some more flex instead of patching. Might be a lot quicker and easier