Moyer, Neil; Chandra, Subrato; Rotvold, Lisa; Applegren, Ralph
The Eastern Dakota Housing Alliance has completed 8 of 20 planned multi-family and single-family dwellings on Selkirk Circle in Grand Forks, North Dakota. Four twin-home (duplex) units were completed in March of 2003 (Phase I) and four more identical units were completed in February of 2004 (Phase II). Four additional units (Phase III) are due for completion by mid-summer, 2004. Design assistance and performance testing were provided by the Building America Industrialized Housing Project with the goal of achieving up to 50% energy savings over the 1993 Model Energy Code.
To approach this level of savings, various envelope and equipment upgrades were assessed through DOE 2 computer simulations. Base case, Phase I and Phase II homes were modeled including input from envelope and duct leakage testing. Annual combined gas and electric utility savings estimates ranged from 25% on Phase I homes to 35% on Phase II homes over the base case unit built to local minimum standards. A cost comparison of standard and improved systems was also performed.
The use of Extruded Polystyrene (XPS) rigid foam sheathing and tankless gas water heaters were two features, considered innovative by local standards, providing much of the increased energy savings of the Phase II homes over Phase I. The decision to use insulated sheathing was driven by a tripling in the price of plywood during the summer of 2003, making it comparable to the price of R-10 XPS foam. Whole house tankless gas water heaters, far more popular overseas than in the U.S., were costly to purchase and install compared to typical gas or electric choices, but provide substantial savings. The size of a small suitcase, these units saved valuable space in the compact Selkirk home design and are claimed to last 20 years or more.
Buildings - Ducts
Florida Solar Energy Center and Chasar, David, "Cold Climate Case Study; High Efficiency North Dakota Twin Homes" (2004). FSEC Energy Research Center®. 531.