As part of its building envelope work, the Northwest Energy Efficiency Alliance (NEEA) focuses on commercial secondary windows' technical potential and market transformation opportunity. Secondary windows are currently available in the market, however, less is known about the relative cost and performance of products with panes of non-glass materials such as acrylic or film as compared to those with glass panes. Pacific Northwest National Laboratory (PNNL) with support from NEEA evaluated the effectiveness of non-glass secondary windows in improving the window performance of commercial buildings in the Northwest.
This summary provides the findings of PNNL’s field evaluations which examined the thermal and acoustic performance of three commercially available, non-glass interior secondary windows. Lastly, a comparative analysis of initial cost, energy savings, noise attenuation, and subjective factors such as optical clarity and aesthetics is included.