How to Install Thermaflex Ducts

Design a route for Thermaflex ducts, preferably with a large central duct feeding branches to individual heating/cooling spaces. Size the ducts to the airflow of the heating/cooling unit, for both supply (of heated or cooled air) and return (air coming back to the unit from the house). Thermaflex comes in 25-foot lengths in sizes from 4 to 16 inches with varying amounts of insulation. Supply and return ducts must be balanced to handle the same amount of airflow.

Route Thermaflex ductwork through floor or ceiling joists or in wall cavities, depending on the design of the house. Run it between joists in floors and ceilings, when possible, securing it with metal hanger straps attached to joists or with Thermaflex's snaplock circular clamps or flextie supports. Run Thermaflex over joists in an attic and affix it in places to keep it from blowing around.

Use special Thermaflex boots, elbows and assemblies to maneuver around obstacles or connect sections of ductwork. Avoid tight turns or sharp bends or obstacles that might crunch or crimp Thermaflex. Slight depressions, which affect only the insulation, may not damage the duct. Prevent any tearing or damage to the polyethylene outer covering.

Eliminate any routings through high-humidity areas which might cause condensation to build up. Avoid areas of high heat, such as exhaust vents or water heaters, and do not install in any areas subject to sunlight. Seal seams and joints with tape recommended by Thermaflex for use on the polyethylene covering. Cut Thermaflex using a utility knife to trim the outer covering and insulation and tin snips to clip the helix wire.