HVAC Contractor

Meeting the NC 2012 Energy Code Requirements:

The NC 2012 Residential Energy Code requires duct testing in new homes. Total duct leakage rate must be 6% or less, and recorded on the energy efficiency certificate. Use only approved, durable materials to seal ducts; UL181 labeled tape or mastic. Mastic works best on metal ducts and seams. UL181 rated tape works well to seal seams on air handler unit boxes.

NCEEA Resources:

Quick Tips:

  • Seal supply boots and return boxes to the sub-floor or finished ceiling.
  • Wall framing is still allowed to be used for returns, if used seal all seams and joints with mastic.
  • The air handler is under the highest pressure and is often the leakiest part of the duct system. Be sure to seal up the air handler with mastic or UL 181 tape.
  • Flexible ducts should not be pinched, squeezed, or supported in a way that prevents air flow.

Building America Solution Center Resources:

Go Beyond Code:

  • Place ductwork in the conditioned space, this will reduce energy loss. Duct leakage testing is not required when ducts are in the conditioned space.
  • Zero Energy Ready Home Technical Training - Ducts in Conditioned Space, from energy.gov

Go to NCEEA Energy Code Resource Page



The NCEEA has created a document to help the HVAC Contractor become qualified to work on ENERGY STAR jobs and become a leading energy efficient contractor. Click here to download the pdf.