Air Conditioning - Roof located air conditioner

Aloha,

I have a 5 ton a/c unit on the roof. It goes immediately thru the roof, ducting goes straight down about 20', 90 degree elbow, then remains horizontal and goes around the room.

It is in Hawaii. On high humidity days, it sweats and drips at the elbow.

My question, if I am limited on money to insulate the duct exterior, where should I start with the insulation.

Mahalo

if that 20' drop isn't insulated that would be the first place to start.to check the inside of it pull the first elbow off the drop and check up inside it for black insulation.if it is insulated just do the elbows or any exposed metal with a roll of foil faced insualtion out of HD

Aloha, I think your duct is already insulatied on the inside I may be wrong but that is my guess, so if you are getting moisture on insulated duct either the insulation has broken down, your air is restricted moving too slowly and is therefore too cold or your indoor coil is not draining properly and some of the condensate is running down into your ductwork. First make sure the filter and drain line are clean, then if the problem does not go away you could start thinking about insulation.