[villagetinker]

Originally Posted by mulligan

Just do yourself a favor and ask whoever does the work to do a proper heat load calculation including the lanai so you don't over tax your a/c unit.

I agree with this comment, many people end up installing a mini split A/C system for the enclosed lanai. Also, IMHO, you cannot just "ad a duct", as this will affect the airflow in the entire system.