On May 24, 2013, Jim Farlow and Tim Shellhammer of The Farlow Group attended a review of a passive energy designed home under construction in the Old Military Road area. The site seminar was sponsored by the Cape Fear Green Building Alliance and conducted by homeowner and contractor Lucien Ellison, and design consultant for the project, architect Kevin Pfirman. Also presenting information on the home’s precast concrete walls construction was subcontractor Joe Del Guercio of Ideal Building Systems.

The passive design concept strives to reduce energy loss from thermal transfer and air infiltration by integrating all exterior components into a virtually air tight envelope. In the case of this home, that involves insulated concrete walls, triple paned insulated casement and awning windows, spray foam insulation, and a minimally sloped roof using structurally insulated panels without open attic space. Resulting R values are R-50 for the roof, R-35 for exterior walls and R-20 for the floor.

In order to meet passive solar criteria, a structure has to be oriented within 15 degrees of due South to achieve ideal solar gain management over the seasons. Shading from extended roof overhangs minimizes summer heat gain in the 5700 square foot home. As a result of the synergy of design and components, the home can be heated and cooled when necessary with only a 2 ton unit.

The home is presently dried in, with interior finishes due next. This will be a fun project to follow, including its performance over time.