Building envelopes are among the most complex issues for preservation and renewal projects. Modern building envelopes were built at a time when energy conservation was not a concern. Now, however, upgrades to improve energy performance are frequently necessary. Design teams are increasingly multi-disciplinary and can apply an array of simulation technologies and testing programs to evaluate assemblies and diagnose materials.  
 
The exterior envelope study and mechanical system replacement for the Smithsonian Institution’s National Air and Space Museum includes stone testing, water and air leakage testing, hygro-thermal analysis (WUFI), computational fluid dynamics (CFD), and energy modeling. QEA has found that by using simulation tools that analyze and predict energy, lighting, ventilation, thermal, and moisture performance, high-performance envelope solutions can be achieved.  
 
A grant from the Maryland Historical Trust funded the study of energy efficiency upgrades to provide cost savings for Greenbelt Homes, Inc. This New Deal-era planned housing cooperative was constructed in phases between 1935-1942 and is located in Greenbelt, Maryland, just outside of the nation’s capital. Through detailed evaluation, modeling, and cost benefit analysis, QEA developed and recommended sensitive energy retrofit approaches for the building envelopes of these historic homes.