Aluminum foil tape for HVAC relies on what’s known as a pressure-sensitive adhesive (PSA) for its inherent stickiness.
Aluminum foil tape is truly intended for sealing air ducts. Aluminum foil duct tape must be permanent and able to withstand the prolonged heat and air pressure for the lifetime of the duct. It may even need to be flame retardant to meet some building codes. Aluminum foil tape for HVAC is the true top of the line, a high tensile, hardworking tape.
If you're tackling an HVAC job at home, aluminum foil tape should be your go-to. Foil tape is flame resistant, holds up in extreme temperatures, and sticks strong in high humidity. If you'd rather not mess with duct mastic to seal up your HVAC system, aluminum foil tape is a solid alternative.