Historic homes, because of their age and condition, offer considerable potential for energy retrofits that can reduce their energy use and utility costs as well as improve living conditions for their owners.  However, few reliable studies are available to inform the owners of historic homes in hot and humid regions as to appropriate retrofits for their homes, and none offer any prioritization of these potential retrofits.  Such guidance is needed both to ensure that the retrofits are appropriate for older homes and, more importantly, that they meet the requirements typically placed on these historic homes and do not impact their cultural value. 


To address this, a team of researchers from UTSA’s Center for Cultural Sustainability (CCS) has conducted a study to identify and prioritize cost-effective retrofits for historic homes in hot and humid regions.  This interdisciplinary team was led by Professor William Dupont, CCS director, and included Professors Hazem Rashed-Ali, Randy Manteufel and Thomas Thomson.  Graduate student Levi Sanciuc contributed as well. 

The team analyzed four homes in San Antonio dating to the beginning of the 20th century and all located in historic districts.  Through conducting detailed measurements, assessments of physical conditions, infrared thermography, and performance simulation, the team identified a series of retrofits that offered the most energy savings and economic potential for homeowners, while not impacting the historic character of the homes.  Primary retrofits recommended by the study include attic insulation, sealing of HVAC ducts, radiant barriers, weather stripping and attic ventilation. 

Some retrofits were not recommended because of their long payback periods, their potential impact on the home’s historic character, or both.  These include window replacement, storm windows, and adding wall insulation or a vapor retarder.
In another significant finding, the study found that within the San Antonio real estate market, old homes with at least one green upgrade sell approximately 10 percent higher than identical homes without such upgrades.

In a second phase of the project, Dupont and colleagues are currently evaluating radiant barriers as a potential retrofit for historic homes in hot, humid regions.  The project, funded by the National Center for Preservation Technology and Training (NCPTT), involves retrofitting the attics of up to 10 historic homes with radiant barriers and evaluating the impact of this retrofit on reducing the energy use and utility costs of the home.  Similar to the initial project, this study uses a mixture of energy use monitors and utility data analysis to evaluate the retrofit’s impact.  Initial results from this study are expected by early 2017. 

Visit ccs.utsa.edu for more details.

- Dr. Hazem Rashed-Ali, Associate Professor Associate Dean of Research and Graduate Studies, UTSA