The studies listed here provide useful information for those interested in sustainability and energy efficiency as it relates to historic preservation. A listing on this page does not indicate endorsement by the National Park Service and views or opinions expressed are not necessarily those of this office.
The Effects of Energy Efficiency Treatments on Historic Windows—Published in January, 2011, by the Center for Resource Conservation in Boulder, Colorado. This study focuses on empirical testing of the energy efficiency and economy of a range of options for upgrading the energy performance of historic windows. It involved retrofitting windows in a test home in a historic district in Boulder, Colorado as well as testing in a laboratory facility developed for the study. Summary tables cover the eleven different preservation treatment options that were investigated and then compared to a new vinyl window. Most of the proposed treatments were able to outperform a new vinyl window. The study has lots of technical information and the results from both field and lab testing. While there is not a great deal of detail about the cost of the various options, there is enough cost information to provide relative payback savings.
Measured Winter Performance of Storm Windows—A 2002 study completed by Lawrence Berkeley National Labs. In testing under actual winter weather conditions, the study finds that a north-facing, wood, double-hung, single-glazed (AND intentionally leaky), sash in combination with a low-E storm window, performed very similarly to the standard low-E vinyl replacement window.
Testing the Energy Performance of Wood Windows in Cold Climates—A 1996 study which showed that window replacement will not necessarily reduce energy costs more than an upgrade utilizing the existing sash. It found that effectively sealing between the window frame and rough opening was important in reducing the infiltrative thermal losses associated with any window renovation. Storm windows, either existing or replacements, were found to be effective in reducing both infiltrative and non-infiltrative losses. This study was funded by the State of Vermont Division for Historic Preservation utilizing a grant received from the National Center for Preservation Technology and Training of the National Park Service.
Thermal Performance of Traditional Windows—Published in 2008 by Glasgow Caledonian University for Historic Scotland. This study investigated various options for reducing heat loss through windows. Among the options tested were secondary glazing systems (storm windows), insulating shades, and more traditional window treatments like shutters and curtains. Although secondary glazing was found to be the most effective option (reducing heat loss by 63%), timber shutters were also found to be effective (reducing heat loss by 51%.) Findings indicate that the most effective reductions in heat loss were attained by combining several treatments.
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Technical papers prepared for Historic Scotland—a collection of reports with topics that include thermal performance of windows, in situ U-value measurements, and energy modeling.
Window repair and retrofit studies and research compiled by the California Office of Historic Preservation.