Irony of ironies, that roll of duct tape you have is not designed for use on ducts.
I’m talking about those sheet metal tubes used to move air in HVAC systems. Most duct tape-the utility grade you buy at the hardware store-will not stand up to the changes in temperature and humidity that duct work goes through. It will fail, usually pretty quickly, when exposed to these conditions.
That failure will lead to air leaks and have a major impact on the efficiency of your system.
There are duct-type tapes intended for sealing and seaming metal duct work, but it needs to be made to the specs that a building inspector will be looking for when passing your installation.
Quite often, the suitability of a tape product for use on ducts will be printed directly on the tape. It is designed to hold tight on rough or unfinished surfaces and also intended to keep holding as the metal expands and contracts.
Harrison Bros. Inc.
47 N. Chatham Pkwy.
Chapel Hill, NC 27517