Many buildings today have a portion of their ductwork either exposed to the outdoors or improperly insulated.


The radiant heat from direct sunlight onto these exposed ducts significantly increases the ambient temperature within the ductwork. This trapped heat forces the air conditioning system to first cool the ductwork down before it can properly cool any room in the building. Unwanted duct heat gains can be minimized through the use of high-reflectivity/high-emissivity “cool duct” coatings, which have the potential to reduce the solar heat gains by ~80%. Properly insulated ducts can help further reduce heat gains from warm attics.


With regards to Cool Ducts, WCEC attempts to answer these questions:


  • What is the prevalence of exposed ductwork in California? How do we develop a methodology to accurately count the exposed ductwork?
  • How much energy can be saved using “cool duct” coatings and how many years is the payback?
  • How effective is insulation for ductwork?
  • How much will cool ducts reduce beneficial wintertime solar heat gains?


The first research goal is to determine the prevalence of exposed ducts. With this knowledge, WCEC can then study the energy savings per building and map the savings cumulatively over California. Ultimately, WCEC’s findings should determine the efficacy of cool ducts and duct insulation on energy usage with the goal of creating prescriptive strategies to help reduce overall energy consumption.