Daylighting opportunities were an important element within the design, both in terms of human perception and energy optimization. In order to meet the goal of zero net energy performance, careful selection and placement of window and door natural lighting was a paramount feature while still achieving high performance levels of envelope air leakage and thermal achievement. Included in that strategy, was the use of well crafted “french style” swing and slider doors to serve as both egress and daylighting solutions. Given the use of double wood stud wall (R40+) exterior wall construction on the upper level and Logix ICF (R27) concrete on the lower level walls, any type of exterior door was a significant drop-off in thermal performance, so it only made sense to use the doors (5 total) as daylighting features as well, which allowed a reduction in the total windows required for great natural light. Including features like the operable sidelites to the two main entry doors described above, only added to the natural ventilation options. Additionally, placing the large (8’x8’) Marvin french slider door on the lower level directly below the (12’x8’) NanaWall folding/sliding glass door assembly above on the upper level leading into the 3-season room, permits the lower level to be completely protected from summer rains, allowing it to be open even during inclement weather, just like the entry sidelites. The large slider also floods enormous amounts of light into the lower level.
Three other carefully designed features also serve to gather light and flood natural light throughout the upper level of the home. First is the breakfast nook bump-out (3’x8’) in the kitchen area, with operable windows on three sides, that gathers light from sunrise till late in the afternoon. Directly opposite this on the other side of the home is the dining area and its folding/sliding glass NanaWall that opens into a large (14’x16’) 3-season room, which also gathers light from sunrise to sunset with its three walls of operable slider windows and french swing door to the rear deck. Directly adjacent to the folding/sliding door assembly is the living room area with a large, half round, fixed picture window, with operable double hung windows built integral to both sides. The net result of all three of these features is a flood of natural light and a bright airy feeling on even the darkest days, even when the folding/sliding door assembly is closed during the winter. Options for cross-ventilation are numerous, and all the air tightness and thermal energy goals have still been achieved.
In the winter months and during portions of the swing seasons, when natural ventilation is not employed, the whole house is mechanically ventilated utilizing a Fantech SHR3005R dedicated air-to-air (92% efficient) heat recovery exchanger and a Fantech HEPA filter air supply system that provides fresh air throughout the house. In addition, only zero VOC paints (Glidden Professional) and cabinets (Executive Cabinetry) were used, helping to minimize or eliminate any toxic air pollutants inside the house. The attached garage is mechanically exhausted on demand and its walls and ceiling are completely insulated and finished with drywall and paint to prevent contaminants from entering the house.