As a New York Energy Star home builder, Viola incorporates several energy efficient systems even in their baseline home, including a 90 AFUE furnace, Energy Star windows, and R-19 above grade wall cavity insulation. Under the NYSERDA challenge, Viola’s home design will be changed on multiple fronts to increase expected performance. Targeted measures are expected to result in a HERS score of 92 and a reduction of whole house energy use of 38% over their baseline home. Construction on the Viola home began mid-April, 2008. This website will track the progress ofconstruction through to project completion.

Poured Wall Foundation

Viola has whole-heartedly accepted the challenge of building a tighter and more energy efficient envelope to increase the home’s energy performance. The first component of a tight envelope is starting with a tight foundation. Viola prefers to use poured concrete walls instead of concrete masonry units to result in a tighter basement with lower air infiltration. This practice is something that the builder has arrived at based on blower door tests of both types of foundations, which have pointed towards poured concrete as a tighter system.

Reducing Conditioned Area

NYSERDA recognizes that the smaller the footprint of a home, the less resources and energy it will consume over its lifetime. As a result, 2500 sqft was set as the maximum finished square feet of any single family home built under the program. To meet program guidelines while providing a highly livable space, Viola reduced the size of their first floor sunroom in their proposed plans.

Optimizing Framing

For the NYSERDA challenge home, Viola moved stud spacing to 24” on-center, which conserves materials and improves the thermal performance of the envelope by permitting more insulation to be used in the wall cavities. Raised heel trusses were also specified to allow insulation to be blown all the way to the eaves. Where needed, ladder blocking (pictured) permits greater insulation to be installed in cavities.

Above Grade Walls

As a baseline measure to air sealing the above grade walls, Viola fully sheathes their homes and tapes the joints. Interior to the sheathing, NCFI’s InsulStar closed cell spray polyurethane foam will be applied to the band joist cavity and the above grade walls to provide a cavity R-value of 33.6. To cap off the above grade wall insulation, Dow’s Tuff-R polyisocyanurate foam board insulation will be fastened to the exterior and taped, providing additional air sealing benefit and another R-9.8 of continuous insulation at 1.5” thick.