In the fall of 2010, a multiyear pilot energy efficiency retrofit project was undertaken by Greenbelt Homes, Inc, (GHI) a 1,566 home cooperative of circa 1930 and 1940 homes in Greenbelt, Md. GHI established this pilot project to serve as a basis for decision making for the roll-out of a decade-long, community-wide upgrade program to incorporate energy efficiency improvements to the building envelope and equipment with the modernization of other systems such as plumbing, mechanical equipment, and cladding. This report summarizes the Phase 2 (of 3) activities in the pilot program, including crawlspace, attic, and wall upgrades, testing, and energy use summary. In addition to this summary of retrofit upgrades, this report includes an analysis of interior insulation options, which were of interest to some GHI members seeking to maintain the exterior “block” profile of the original buildings. The report also includes an analysis of heating and cooling system options, costs, community impact, as well as a cost-benefit analysis.
These High Performance Scopes of Work are intended to assist builders and trade contractors to build high performance homes efficiently and cost-effectively. They may be adopted and used in whole by a builder or trade contractor.
Innovation in construction technology has been often driven by a desire to improve performance (e.g., reduction in energy use) and/or to gain efficiency in the construction process (e.g., garage portal frames, SIP construction). On the other hand, a re-evaluation of existing code provisions is often prompted by a desire to align conventional practices more closely with engineering estimates (e.g., wall bracing provisions of the International Residential Code (IRC)). Because conventional practices have a history of successful field performance, a re-evaluation task typically involves (1) development of analytical methods that are representative of the actual system performance, and (2) establishment of appropriate applicability limits on the prescriptive requirements (e.g., wind speeds less than 100 mph).