John J Macaulay
OS House, designed by Johnsen Schmaling Architects.
A LEED Platinum–certified single-family home, this 1,940-square-foot structure occupies a narrow infill lot on the edge of Lake Michigan. The building is a simple rectangular volume with a series of outdoor rooms such as an entry court, elevated patios, and a main-level terrace. A one-car garage with bike storage also is integrated into the volume of the house.
Oriented along the north-south axis, the house is designed to take advantage of lake breezes in the summer and high-performance, low-E, argon-filled operating windows help with cross-ventilation. During the winter, the house is mechanically ventilated with an outdoor air supply system and heat-recovery system. Heating and cooling is supplied by a geothermal ground-source heat pump with a vertical-loop system.
A hybrid building envelope featuring high-efficiency glazing and a super-insulated rainscreen system addresses a desire for transparency and the need for superior thermal performance. Along the edges of the outdoor spaces, the 8-inch-deep rainscreen transitions into a scrim of aluminum rods that create boundaries but maintain a sense of transparency. Closed-cell expanding-foam insulation provides R-values of 34 and 53 in the walls and roofs, and wood-framing techniques used decrease thermal bridging and increase insulated surface areas.
About 70 percent of the house’s electric power is generated by a 4.2kW photovoltaic system that comprises PV laminates on the roofing membranes and a freestanding array. A solar hot-water panel preheats water, whichis then distributed by insulated pipes and an on-demand pump. Interior materials were chosen with an eye toward durability, low maintenance, toxicity, and sustainable, recycled and rapidly renewable content. Near-zero construction waste was achieved.
By the numbers:
Building gross floor area: 1,940 square feet
Number of occupants: 4
Percent of the building that is daylight: 100
Percent of the building that can be ventilated or cooled with operable windows: 100
Total water used, indoors and outdoors: 13,900 gallons per year
Calculated annual potable water use: 7.16 gallons per square foot per year
Total energy (MBtu per yr): 41.7
HERS performance rating: 33
Percent total energy savings: 67
LEED rating: Platinum, LEED for Homes v.1
AIA COTE 2011 Top Ten Green Projects
Click on the project names below to read more about each winner.
For more information on each project, including extended slideshows, click on the individual projects in the sidebar at left. To access a database of past Top Ten projects, visit aiatopten.org. ECO-STRUCTURE will be covering the 2011 COTE Top Ten projects in depth in its July/August issue.
