KANEOHE—The doors will be opening to what’s been touted as “the greenest home in Hawaii.”
The public is invited to see the home on July 30 from 10:00 a.m. to 3:00 p.m. at 45-610 Huinawai Place in Kaneohe.
The home was designed by Archipelago Hawaii and built by Mokulua Woodworking Ltd. Visitors to the open house can learn firsthand about the many green design and construction options implemented during this project that includes a custom photovoltaic system designed and installed by RevoluSun. The home has been awarded the National Green Building Standards GOLD level by the National Association of Home Builders (NAHB) a first for any home in Hawaii. Mokulua Woodworking partnered with Archipelago Hawaii, creating a “green team” to design and build the home.
“At first we were apprehensive to ’Go Green’ because we thought it could lead to cost overruns and sacrifices in design,” said Kenny Arakawa, homeowner. “We were amazed at how affordable green building could be with the right designer-builder team, with long-term savings on energy and water.”
In 2007, NAHB and the International Code Council (ICC) partnered to establish a much-needed and nationally recognizable standard definition of green building, called the ICC 700 National Green Building Standard™ (NGBS). It is the first and only residential green building rating system to undergo the full consensus process and receive approval from the American National Standards Institute (ANSI). The Standard defines green building for single- and multifamily homes, residential remodeling projects, and site development projects while still allowing for the flexibility required for regionally appropriate best green practices.
This NGBS Standard awards four levels of certification: Bronze, Silver, Gold and Emerald, based on points earned in seven different categories:
1. Lot design, preparation and development
2. Resource efficiency
3. Energy efficiency
4. Water efficiency
5. Indoor environmental quality
6. Operation, maintenance and builder/owner education
7. Additional points from any category
Unlike LEED (Leadership in Energy Efficiency and Design) certification administered by the United States Green Building Counsel (USBGC), which does not require a project to earn points in every category to achieve LEED status, the NGBS Standard requires the project to place with a minimum of points in every single category.
“The NGBS standard ensures the home project is holistically a green project, as the project is rated on all seven categories and must score a certain amount of points in each category to qualify,” said Michael Fairall, owner of Mokulua Woodworking, Ltd.
The 3,000-square-foot, two-story home took four months for Archipelago Hawaii to design. Deconstruction of the original one-story, 1,500-square-foot home on the 11,509-square-foot lot began in February and Mokulua Woodworking completed the project in June.
Some of the sustainable design and construction elements include:
· A custom-designed 4.8 kW PV system powered by 15 SunPower 320 panels. The most efficient panels in the world, this system offsets 8,516 tons of carbon from entering the atmosphere annually and saves the equivalent of 622 trees planted. Over the life of the system, the Arakawa family can expect to save $97,376 that they would have had to pay to the utility (based on today’s price of electricity with a very conservative annual average escalation of 5.9 percent).
· The inside of the home includes all LED-recessed lighting, and all appliances and fixtures are Energy Star-rated.
· Mokulua also used pre-engineered materials such as structural beams, I-beams, trusses, which allows for as little waste as possible when the items arrive to the site ready for construction.
· The construction team made all trim items from recycled materials.
· Mokulua also used an engineered truss system to allow for very little waste for roofing.
· Construction crews used a Pro-rock material for the drywall, which is a partially recycled drywall. This product provides for a good breathability factor with very little off-gassing. Meanwhile, the carpet is post-consumer product with recycled fibers and a laminate flooring that is 80 – 85 percent post consumer product.
Site Prep/ Deconstruction/Construction
· Before the job start, Mokulua crews roped off areas that were to be off limits as to not disturb the existing vegetation. In addition, there was a very stringent schedule to pour the base slab, to get on and off the site within 12 days. This was extremely important in minimizing runoff.
· During deconstruction, the Mokulua team was able to save a large number of the original structural beams. Most of these were used to create the back lanai.
· Every week the Mokulua crew recycled all plastic, cardboard and wood during the build out.
· Mokulua contractors also saved any metal items and recycled all wood scraps for nailers, etc.
· In addition to saving and re-using as much wood items as possible, Mokulua crews framed the home in a way to minimize lumber. For example, by creating equal-sized rooms in increments of 16 inches, Mokulua was able to use less 2x4 boards. The Mokulua team took into consideration that plywood comes in 8-foot-sheets, so by designing 9-foot exteriors, Mokulua Woodworking was able to use a full sheet of plywood every time. In fact, due to the careful design, during the entire job Mokulua crews only created one, 40-foot container of waste. Compared to other home construction jobs that create four to six 40-foot containers of waste, this is truly significant.
· A stormwater and conservation plan was implemented early on to ensure efficient and natural water management during and after construction. Natural irrigation procedures were also implemented to offset a pressurized irrigation system.
· Archipelago Hawaii designed the home to be completely insulated, establishing a thermal envelope that provides for very little leakage in terms of air conditioning. Meanwhile, the window design allows for cooling trade winds to ventilate the home, so that the split air conditioner for the downstairs area and the master bedroom will only need to be used a dozen times a year, further reducing the energy load.
· Water use was also carefully considered and managed. Archipelago Hawaii designers chose all low-flow plumbing.
· The landscaping was also developed to be sustainable in coordination with Mokulua and Stephen Haus, ASLA, who recommended only low-water, indigenous plants for the front and back yards.