How much does it cost to perform a deep-energy retrofit at a 100-year-old single-family home? Thanks to a recent study in Utica, New York, we now know the answer: about $100,000.
The research was sponsored by New York State Energy Research and Development Authority (NYSERDA), an agency that administers programs funded by public benefit charges tacked onto electric utility bills. The program paid for deep-energy retrofits at four wood-framed buildings in Utica, New York.
The project manager for the study was NYSERDA engineer Greg Pedrick. At the recent Better Buildings by Design conference in Burlington, Vermont, Pedrick gave a presentation, “Research Findings and Momentum for Deep Energy Retrofits,” explaining the scope of work and summarizing the costs of the retrofits.
A big fan of deep-energy retrofits, Pedrick explained, “I want to see a fatter house with a smaller mechanical system.”
Pedrick’s team selected four wood-framed buildings; brick buildings were deliberately excluded. All are owned by low-income families who had applied for weatherization assistance. Three of the buildings are single-family homes; the fourth is a duplex. All of the buildings are about 100 years old.
The work was paid for by NYSERDA; there were no out-of-pocket expenses for the building owners.
The researchers’ goal was to reduce energy use by 75%. To achieve this goal, the plan was to retrofit slab floors to R-10, below-grade walls to R-20, above-grade walls and roofs to at least R-40. The windows would be upgraded — either with low-e storm windows or new windows — to achieve a maximum U-factor of 0.25. The airtightness goal for the homes was 0.15 cfm @ 50 pascals per square foot of surface area.
To insulate the basement floors, the contractors first installed a layer of Platon dimple mat on top of the existing concrete slabs, followed by R-10 rigid insulation and a layer of Durock cement…