Right now, the short answer now is: maybe.
Craig Drumheller wanted to know why the ductwork for his home air conditioning system ran through the highest and hottest portion of his attic, making the system work extra hard to keep the conditioned air cool. Why was the practice of burying the ductwork in the attic insulation prohibited in his jurisdiction?
As the director of codes and standards at NAHB, Drumheller knew that burying ductwork in the attic insulation was not explicitly prohibited by the building code. He also understood that code officials were concerned about condensation on the ducts, causing moisture problems, displaced attic insulation and possibly reduced energy efficiency.
Drumheller talks about the problem – and what NAHB did to solve the issue for the 2018 edition of the International Energy Conservation Code to be published this fall – in the latest issue of the Journal of Light Construction.
After research, Drumheller found that burying ductwork in attic insulation actually saves energy, and the concern about condensation was only regional when employing higher efficiency levels of the new energy codes: The condensation issue could be addressed with higher levels of duct insulation.
When he heard that some NAHB builder members were also wondering why they were prohibited from burying ducts in the attic insulation, Drumheller worked with the Construction, Codes and Standards committee members and the industry experts at Home Innovation Research Labs to amend the code and clarify that “burying” attic ducts to insulate them from heat and cold is an appropriate option throughout many parts of the country.
However, there may be different requirements depending on an area’s typical temperature and humidity factors.
Read how they did it, and why and when home builders might consider this option in their next construction project.
Bonus for NAHB members: Home innovation Research Labs has also written a TecSpec that details the code requirements, techniques and benefits of burying ducts in attic insulation.
