Homebuilders moving beyond Energy Star; Illinois gets its first net-zero energy ready ‘Challenge Home’
Ever thought about building a very energy-efficient custom home? What if this home would be one of the greenest homes of its kind in the country?
Weiss Building & Development LLC and Tom Bassett Dilley Architects in the Chicago area have accomplished just that in completing the first home in Illinois meeting the U.S. Department of Energy’s newly-developed “Challenge Home” certification requirements for comfort, health, quality, durability and advanced technologies. It’s the 17th Challenge Home in the U.S.
This proves that next-generation green homes are making their way eastward. The West Coast is no longer the only proving ground for next-generation home construction. THAT is an important milestone in my book.
One of, if not, the most important professionals advocating for and helping to enable Challenge Homes is Samuel Rashkin, widely viewed to be the creator of the Energy Star home program as the Chief Architect of the Department of Energy’s Building Technologies Office. In this Energy Fix video excerpt, Rashkin touches on how he believes “net-zero energy ready” homes will catch on within 5-10 years.
In addition to meeting numerous other stringent energy requirements, a Challenge Home requires that homes be net-zero energy ready. That means the home must be able to function on very little energy provided by utilities and emit and zero carbon emissions annually. Go here for the full list of requirements from the Department of Energy.
For its efforts, the residence Weiss Building constructed also has earned the National Association of Home Builders’ “Green Building Emerald” certification – their highest green certification level — and is “Indoor Air Plus” approved by the U.S. Environmental Protection Agency.
The 3600-sq.-ft. home, which sits on a 75 x 200 foot lot, was completed for less than $135 per square foot. This suggests, at least in Downers Grove, IL, a Chicago suburb, that “green” homes do not have to cost more than code-built homes.
The comfortable nature of a green home is often overlooked in the evaluation of a green, high-performance home.
“People have accepted a false reality that different parts of a home will have different temperatures. It does not have to be that way,” said Brandon Weiss, the construction company’s founder. “Comfort is a terrific side effect of building a true high performance home that not everyone considers, but something they always appreciate once they live in the home.”
For the Challenge Home, Weiss Building applied a holistic approach by sourcing third-party certified materials, such as GreenGuard Gold specified products to ensure improved indoor air quality.
In addition to high efficiency windows, the home contains return air registers in all rooms except bathrooms, laundry and the kitchen. This keeps air circulating and maintains stable temperatures.
Part of the final performance testing of the new home was through third-party testing. Weiss Building tested the home for duct tightness, air tightness, and indoor air quality. The final numbers for the blower door test were 1.25 ACH@50, 60% better than Challenge Home requirements. The insulation values, mechanical systems, lighting and appliances led to a Home Energy Rating System (HERS) score of 35, meaning the home was 65 percent more efficient than a code-built home.
A special methodology was applied to the walls, which were built on a rainscreen. A rainscreen is the exterior weather-facing surface of an exterior wall that directs water away from the dry insulation where it otherwise might cause problems such as mold formation and water leakage. It gives bulk water a place to drain without pressure.
Outside, plywood sheathing with two inches of exterior foam helps reduce condensation and conductive heat loss. The siding was installed ¾-inches from the weather barrier on furring strips, with vents at the top and bottom of the wall with a kickout flashing at the base to allow for any moisture behind the siding to drain and shed away from the home.
The siding used for the home has a 50-year warranty on the materials and 30 years on the finish. The installation of the siding also prolongs the life of the finish because of the drying out potential and helps regulate even temperatures on both sides of the product.
Included in the budget was an extensive underground storm water system and 35-foot deep caissons built to support the foundation relative to soil conditions and lot elevations. The concrete foundation is reinforced with steel and rises 3 and 1/2 feet above grade to facilitate drainage and thus avoid costly, and unhealthy, moisture and mold problems.
Finish highlights include doors that contain no added urea formaldehyde with water-based, non-toxic finishes. The bamboo floors were sustainably harvested; they are 154 percent harder than wood from red oak trees and have a 10-coat finish to prolong durability as well as improve the impact resistance of the wood.
All of the insulation in the home meets GreenGuard Gold standards for indoor air quality, as does the drywall, tile backer board, tile mortar, caulks glues, stains, and drywall finishing products. The tile grout used is epoxy based and offers stain protection without requiring sealing or maintenance. GreenGuard certification ensures that a product has met some of the world’s most rigorous and comprehensive standards for low emissions of volatile organic compounds (VOCs) into indoor air.