BA-1303: Transformations, Inc.: Partnering to Build Net-Zero Energy Houses in Massachusetts

Transformations, Inc. is a residential development and building company that has partnered with Building Science Corporation to build new construction net-zero energy houses in Massachusetts under the Building America program. This report covers all of the single-family new construction homes that have been completed to date. The houses built in these developments are net zero energy capable homes built in a cold climate. The set of measures offered by the developer exceeds the 30% energy saving goals set by the Building America program for New Homes in the cold climate for 2013. The houses will contribute to developing solutions and addressing gaps in enclosures and space conditioning research.
Transformations, Inc. is a residential development and building company that has partnered with Building Science Corporation (BSC) to build new construction net-zero energy houses in Massachusetts under the Building America program.
There are three communities that are being constructed through this partnership: Devens Sustainable Housing ("Devens"), The Homes at Easthampton Meadow ("Easthampton"), and Phase II of the Coppersmith Way Development ("Townsend"). This report covers all of the single-family new construction homes that have been completed to date.
The houses built in these developments are net-zero energy capable homes built in a cold climate. The set of measures offered by the developer exceeds the 30% energy saving goals set by the Building America program for new homes in the cold climate for 2013. The houses will contribute to developing solutions and addressing gaps in enclosures and space conditioning research; specific topics included the following:
Transformations, Inc. is a residential development and building company that has partnered with Building Science Corporation (BSC) to build new construction net-zero energy houses in Massachusetts under the Building America program.
There are three communities that are being constructed through this partnership: Devens Sustainable Housing (“Devens”), The Homes at Easthampton Meadow (“Easthampton”) and Phase II of the Coppersmith Way Development (“Townsend”). This report covers all of the single-family new construction homes that have been completed to date in Devens and Easthampton, as well as three homes in Phase II in Townsend. Currently, there are six houses that have been completed in the Devens development, seven houses in the Easthampton community, and three houses in the Townsend development.
Transformations, Inc. completed one community development and multiple custom homes prior to partnering with BSC. Since 2006, the developer has been developing strategies for cost- effective super-insulated homes in the New England market. Several construction methods for walls, roofs, basements, as well as mechanical and ventilation systems have been tested by the developer. After years of using various construction techniques, Transformations, Inc. has developed a specific set of assemblies that is implemented in the houses in all three developments. These assemblies exceed the requirements of current building codes and are financially viable for the developer.
The houses built in these developments are net-zero energy capable homes built in a cold climate and contribute to research on topics including high R-value double-stud walls, high efficiency ductless air source heat pump (ASHP) systems (“mini-splits”), including occupant satisfaction and feedback; financing of photovoltaic (PV) systems; and basements versus slab-on-grade construction. The research questions were as follows:
With the high efficiency features used in the construction of these homes, the houses meet the requirements of the U.S. Department of Energy’s (DOE) Version 2 of the Builders Challenge program—the DOE Challenge Home—under the prescriptive path. The program requires that the homes are 40%–50% more energy efficient than a typical new home and are certified through a third-party company. The program requirements are as follows:
The Devens development is a net-zero energy community located in Fort Devens, Massachusetts, where the developer was awarded the contract to build eight one- or two-story single-family houses of 1,064–1,820 ft2.
Figure 1. Devens sustainable housing site plan
As of August 2013 all of the homes in the development have been completed and occupied.
Figure 2. (L) Farmhouse (Lot 1); (R) Greek Revival (Lot 2)
Figure 3. (L) Victorian (Lot 3); (R) Farmhouse (Lot 4)
Figure 4. (L) Greek Revival (Lot 5); (R) Saltbox (Lot 6)
Figure 5. (L) Custom Saltbox (Lot 7); (R) Ranch (Lot 8)
The houses feature three or four bedrooms as well as an optional basement. The construction of the houses is shown in Figure 6. The enclosure characteristics include full basements with 2 in. of extruded polystyrene (XPS) rigid insulation (R-10) under the slab and 3½ in. of closed cell spray foam (ccSPF) insulation (R-20) at the basement walls, a double-stud wall with 12 in. of ocSPF (0.5 per cubic foot [PCF]) insulation (R-46 nominal) and 18 in. of cellulose insulation in the attic (R-63). The mechanical system consists of two single-head mini-split units, a ventilation unit, as well as a tankless propane water heater. A PV array is also part of the house package.
Figure 6. Wall section with basement
The work performed in the Devens development that will be discussed in this reports includes moisture monitoring of the double-stud walls and heat pump monitoring in the Victorian (Lot 3), feedback from the homeowners on the heat pump performance, and air leakage testing results from all of the houses built to date.
The Easthampton development is net-zero energy capable community located in Easthampton, Massachusetts. Transformations, Inc. parntered with Beacon Communities LLC (a Boston-based dvelopement company) to build 33 one- or two-story, single-family houses of 1,064-2,365 ft2 (Figure 7). The houses feature two, three, or four bedrooms; the development includes market-rate as well as affordable units.
Figure 7. The homes at Easthampton Meadow site plan
Seven houses have been completed . . .
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