IN HAWAII, a great deal of living happens outdoors. Stunning ocean views, expansive skies, scenic terrain and warm weather beckon to residents and visitors year round. To enhance this experience, Honolulu-based Towne Development of Hawaii built a Maui residence that blurs the line between interior and exterior spaces and respects the natural environment. • Called “The Good Home,” the 2,700 square-foot (251-m2) house is unique among the 72 lots in the Koa at Kehalani subdivision in Wailuku, marketed under the Towne Island Homes brand name. The sustainable residence is participating in the Washington, D.C.-based U.S. Green Building Council's LEED for Homes pilot program and serves as a learning tool for its developers and designers. • “As the company looks toward the future, we would like to know more about green building,” says Shane Jackson, director of environmental projects for Towne Development of Hawaii. “The custom home is helping us examine which techniques we can integrate into our production-style home processes.”
THE PERFECT SETTING / The home sits at the end of a street and is oriented to capture the local trade winds that blow nine out of 10 days. Large windows offer views, but the team added smaller window openings within the glazing to control the amount of air that enters the house.
Half the site is on a large slope where indigenous plants play a role in reducing erosion. Area drains feed bioswales connected to an underground dry well that collects water and allows it to slowly percolate into subsurface soils. The bioswales also supply a seepage bed that directs water back into the site to prevent runoff. To create pervious surfaces around the house, the driveway and pathways are composed of spaced concrete and stone pavers.
It would be impractical not to take advantage of the abundant solar power available on the island, so the team harnessed this renewable resource in two ways. First, the team installed a 3.5-kilowatt photovoltaic array on the roof. Calculated with the air conditioner running, the system provides 60 percent of the home’s electrical needs. If future homeowners choose to cool the house with the natural ventilation supplied from trade winds, the PV array will provide a higher percentage of the home’s electricity. The array is on a net metering system and can feed power back into the electrical grid. Mounted to a rack that clips onto the standing seam of the home’s highly reflective metal roof, the system’s construction reduced roof penetrations to lower the risk of leakage.
The sun also powers a solar hot water heater responsible for providing more than 90 percent of the building’s hot water. The system’s 80-gallon (303-L) tank has a pump that runs the water up through the panels and to a circulation line. During design, the team placed all plumbing fixtures within 10 feet (3 m) of each other and included a recirculating line so hot water would arrive virtually on demand. The addition of low-flow faucets and showerheads and dual-flush toilets help minimize water consumption.
INCREASED CONNECTIONS / Strengthening the relationship between the interior and exterior spaces was a project goal, and the team looked for design solutions to make it happen.
“We were trying to figure out how to engage the outdoors, and it was like a light went on: just remove the wall,” explains architect Dennis Stapleton of Milwaukee-based Zilber Ltd., the real-estate-development company of which Towne Development of Hawaii is a subsidiary. “By creating large glass pocket doors, we blended the inside and outside into one space.”Lanais, or verandas, adjacent to the great room and every bedroom also provide easy access outside while deep overhangs and lanai coverings limit thermal gain.
The home’s H-shaped design, numerous windows and 10- to 12-foot (3- to 3.7-m) pocket doors allow daylight to fully penetrate all interior spaces. The glazing systems surpass Energy Star criteria with a 0.35 and 0.27 solar-heat-gain coefficient.
One criterion that the team opted to forego was Energy Star’s window-to-floor-area ratio. Kevin Mantz, vice president of design of Zilber Ltd., thinks it was well worth the trade off.
“Balance is key,” Mantz says. “We decided it was more important to keep the views and daylight. The overall impact is much more positive and from an energy standpoint we’re still way ahead.”
A vegetated roof over the entry foyer and laundry room helps enhance the roof’s thermal resistance, as well as reduces the heat-island effect and absorbs rainwater to minimize runoff.
MATERIAL CONSIDERATIONS / Material selection is a significant issue on an island because anything not produced locally must be shipped. Additionally, the island has limited recycling capabilities and a finite amount of space available for refuse, so the team made construction waste mitigation and on-site recycling a priority.
Through advanced framing techniques that included the use of additional metal hangers and fasteners, the team used less wood in construction. The team stacked wall studs and employed floor-to-ceiling framing to carry vertical loads. These framing measures reduce thermal breaks, which increases the insulation value.
Recycled materials were used in the drywall and insulation. Local blue stone was used as an exterior wainscot and carried into the house in the form of a rock outcropping that separates the dining area from the great room. Many interior materials were locally sourced, as well.
Wanting to offer a clean, crisp interior, the design team gave a modern twist to traditional Hawaiian style. The home’s sleek detailing helped conserve resources. Flooring and lanais are the structural slab, which was ground and polished for rugged elegance. Kitchen countertops are made of 44 percent recycled glass from post-consumer bottles and concrete. Local koa wood was selected for the cabinets. To protect IAQ, base boxes are maple plywood that contains no added urea formaldehyde, and the team selected no-VOC paint and low-VOC water-based stain. Wood flooring came from local eucalyptus. Advanced Energy Star lighting includes recessed cans with compact-fluorescent lamps on dimmers to provide a warm color rendering.
“We set the bar as high as we could to really test ourselves,” says David Koziol, director of marketing for Zilber Ltd. The result garnered local and national accolades.
The Good Home recently won the Design Achievement in Architecture Award from the American Institute of Architects, Washington, and a Washington-based National Association of Home Builders Gold rating. It also achieved a three-star Hawaii BuiltGreen rating from the Honolulu-based Building Industry Association of Hawaii and is on track to obtain a Gold certification from LEED-H pilot.
Team members say public response has been equally enthusiastic. Currently, the house touted as the most environmentally responsive home ever built on the Hawaiian Islands is on the market, but it probably won’t be there long.
>> KJ FIELDS writes about architecture and sustainability from Portland, Ore.
GREEN TEAM REAL-ESTATE DEVELOPER > Zilber Ltd., Milwaukee, www.zilber.com / DESIGN-BUILDER > Towne Development of Hawaii, Honolulu, www.townehawaii.com / ELECTRICAL ENGINEER > Morikawa & Associates, Pukalani, Maui, Hawaii, www.mai-hawaii.com / MECHANICAL ENGINEER > Michael Hattori and Associates Inc., Honolulu, (808) 841-6570 / STRUCTURAL ENGINEER > Englekirk Partners Consulting Structural Engineers Inc., Honolulu, www.englekirk.com / LANDSCAPE ARCHITECT > CHRIS HART & Partners, Wailuku, Maui, (808) 242-1955 / GREEN-BUILDING CONSULTANT > Earth Advantage, Portland, Ore. www.earthadvantage.org
MATERIALS AND SOURCES Koa veneer cabinets with no added urea-formaldehyde and low-VOC finishes and local eucalyptus seligna flooring / King & Zelko Hawaiian WoodWorks, Kailua, Oahu, Hawaii, www.kingandzelko.com Ground and polished concrete countertops with recycled glass content / Lokahi Stone LLC, Honolulu, www.lokahistone.com Energy Star appliances / GE Appliances, Louisville, Ky., www.geappliances.com Energy Star dishwasher / Bosch Appliances, Gerlingen, Germany, www.boschappliances.com Energy Star ceiling fans / Modern Fan Co., www.modernfan.com Dual-flush toilets and low-flow faucets / Kohler Inc., Kohler, Wis., www.kohler.com Low-flow showerheads / Bricor, New Braunfels, Texas, www.bricor.com 3.5 kilowatt photovoltaic panels / Sharp Electronics Corp., Romeoville, Ill., solar.sharpusa.com/solar Cool metal roof / Custom-Bilt Metals, Chino, Calif., www.custombiltmetals.com Aluminum doors and windows / Fleetwood Windows and Doors, San Jose, Calif. www.fleetwoodwindowsanddoors.com HVAC / Carrier Corp. Farmington, Conn., www.carrier.com Irrigation rain sensor with automatic shutoff / Hunter Industries, San Marcos, Calif. www.hunterindustries.com No-VOC paint / Harmony from The Sherman-Williams Co., Cleveland, www.sherwin-williams.com Energy Star dimmable compact fluorescent lighting / Juno Lighting Group, Des Plaines, Ill. www.junolighting.com