Central air condition ducts are often routed through unconditioned zones in the building. A metal duct conveying cool, conditioned air through a broiling attic in summer or warm air through a chilly crawl space in winter may lose a substantial amount of temperature. On average the air ducts leak around 20% to 30% of the air conditioned or heated air. These losses can be reduced by insulating metal ductwork with wrap-around insulation. In order to help improve efficiency, it’s important to seal all of the air ducts joints with HVAC foil tapes.
Purchase duct wrap insulation and HVAC Foil Tape that complies with the FR Grade Class O & UL 723 ASTM E84 Fire Rating standards.
Inspect the span of ductwork to be insulated. Look for signs of air leaks at seams or joints. Seal leaks with mastic duct sealant. Verify that duct segments are permanently fastened together at joints. Wrap the joints with HVAC Foil Tape.
Measure the duct to be insulated. Consult manufacturer’s recommendations for the correct size of insulation to adequately enclose the duct perimeter without compressing the insulation and degrading its heat-resisting properties.
Cut insulation to size with a razor blade knife. Trim two inches of insulation away from the backing on all sides, leaving a flap of backing that will overlap for HVAC Foil Tape.
Wrap the insulation around the duct with the Laminated reinforced Insulation facing.
Clip the overlapping backing together with duct insulation speed clips at 18-inch intervals.
Seal the overlap seam using commercially available pressure sensitive duct insulation HVAC Foil tape.
Butt each adjacent segment of insulation up against the previous segment, overlapping the backing. Tape the overlaps between segments to seal them and form a seamless, continuous segment of insulation enclosing the entire span of ductwork.