air leakage - GreenHome Institute

certified another LEED Platinum home in Wisconsin that features a picture-perfect location on Lake Michigan’s west shore in Racine, Wisconsin. The Scekic-Osborne home is a three-bedroom, 1900 square foot home — an example of the recent trend of home sizes retreating to more reasonable levels rather than the McMansions of yesteryear. The home, designed by Johnsen Schmaling Architects of Milwaukee, mixes modern architecture with a growing design trend known as “micro architecture,” which places a premium on petiteness, design and sustainability.

Download Scekic-Osborne Residence Profile

The home’s modern exterior features exposed steel beams and concrete walls, with expanses of glass offering views through the home to Lake Michigan. Large glazing areas necessitate efficient windows (.29 U-value) as a critical component to the home’s energy performance. The windows give expansive views, but are also a source of energy loss. To make up for this, the home’s design eliminated windows on the north wall and included a number of energy-efficiency strategies to keep the home comfortable:

Exterior walls are 2×6 with full cavity R-34 foam insulation
Cathedral ceilings/roofs are R-53 foam insulation
Foundation walls are R-10 full height exterior insulation
Frame floors are R-54 full cavity foam insulation
Final blower door test: 298 cfm@50 pascals, which translates to a significantly low 0.06 natural air changes per hour
Heating and cooling is provided by a geothermal ground source heat pump
Water heater is a tankless gas unit with 0.98 EF rating
The house also has active solar hot water system and 4.2 kw solar photovoltaic system
Whole house ventilation is provided by a heat recovery ventilator (HRV) at 110 cfm

With the impressively low air leakage rate, these energy systems combined to help the home achieve a HERS score of 33, representing that the Scekic-Osborne residence uses 67% less energy than a new home constructed to building code standards.

To learn more about this unique house – just the second LEED Platinum home in Wisconsin – read the informative article from Sept. 26 edition of the Milwaukee Journal-Sentinel, or download our one page PDF Project Profile on the home.

Chicago’s Yannell residence has gained a lot of notoriety as the first “net-zero” home in the city – capable of producing as much energy as it consumes. Yet another home on Chicago’s far northwest side, the Helenowski Residence, has joined the prestigious ranks of ultra-green LEED Platinum homes. In fact, it’s one of the highest overall point totals ever achieved for a LEED-certified home.

Net-Zero LEED Platinum Home – Zukas Photography

This incredibly energy-efficient home was actually a gut-rehab of a 1950’s brick split-level home, with a major addition, resulting in 3,300 total square feet. The owner has done an incredible amount of work focusing on the Materials and Resources as well as Energy and Atmosphere areas of the home. Some of the sample strategies include:

All drywall was recycled-content (for a $1 per sheet premium)
Salvaged douglas fir from 1800’s fire-damaged building for ceiling
Reuse or salvage for all new interior framing members
Diversion of +90% construction debris
Reclaimed copper for roofing and gutters

The home also has some exemplary energy characteristics that helped achieve a remarkable HERS score of 13, meaning the home uses 87% less energy than a new home built to code.

The remarkable energy performance was achieved by using soy-based spray foam insulation and a meticulous attention to air sealing in the project. The technical data is quite impressive. The blower door testing gave a result of 604 CFM at 50 Pascals. With an estimated volume of 37,725 cubic feet of volume in the house, the air changes per hour at 50 Pa was 1.02, and the air changes per hour at natural pressure is .07. In other words, the home is very tight.

Other strategies contributing to the home’s energy performance include:

Triple-paned Pella windows with FSC-certified lumber.
Geothermal ground source heat pump for HVAC.
Solar photovoltaic panels and a vertical-axis wind turbine to generate electricity.
Motorized blinds control solar heat gain on west-facing (front) windows.
Extremely efficient cold-cathode lighting, up to six times more efficient than LEDs.
Roof is partially reflective white and part vegetative green roof.

The is truly a remarkable addition to the Chicago area’s growing green building inventory and offers many lessons for other builders in the area. Detailed strategies with photos are available at the project’s web site, www.leedhomeliving.com, as well as by downloading the 1-page PDF Helenowski Project Profile that has assembled.

Download the 1-page PDF Helenowski Project Profile

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