Even though Hawaiian residents are known for their love of the outdoors, building green isn’t as prevalent on the islands as one might think. In fact, when Armstrong Builders LLC proposed the LEED Gold-certified Kumuhau Subdivision in Honolulu in 2009, there weren’t many projects in Hawaii using the LEED standard at all. But James Keller, president of Armstrong Builders, and Daniel Sandomire, AIA, the project architect, had decided sustainable residential development was the way to go. “Our project is helping to push other industry leaders to adopt green, sustainable building practices,” Sandomire says.
A few years ago, the Department of Hawaiian Home Lands put out a request for proposals for the subdivision, offering a small bonus for a green approach. “We recognized that a sustainable focus would give us a clear edge over other industry leaders competing for the project,” Sandomire says. It did. Armstrong Builders won the bid to complete the Kumuhau Subdivision and earned the community a LEED Gold rating. The team gave us a rundown of how they did it.
Harness Solar Energy
For each home, Sandomire chose a 2.5-kilowatt, grid-tied photovoltaic system that provides enough energy to support a family of four. A set of 12 panels is located on each carport roof and paired with microinverters that link to the Internet so that homeowners can track energy production in real time.
Account for Outdoor Living
Incorporating a large, covered lanai on each of the 45 homes in the subdivision provided cooling and shading. Also, the canopied porches give each resident a comfortable place to enjoy the scenery from the privacy of their own homes.
Find Effective Cooling Methods
Kohilo-model whole-house fans, super-efficient and extremely quiet, discreetly enhance each of the naturally ventilated homes. “The whole-house fan supports the way one would want to live in Hawaii—indoor-outdoors,” Sandomire says. With a year-round tropical climate, Hawaii is the perfect place to promote natural ventilation, and the whole-house fan allows for this even on days when the winds die down.
The position of each window was carefully considered to minimize direct sunlight and keep the homes cool and comfortable all day long, and the ground-floor ceilings are all either 9 or 11 feet high, allowing for greater air circulation.
Avoid Direct Sunlight
In addition to dual-glazed, low-E windows, Armstrong Builders incorporated fixed awnings over the windows exposed to direct sunlight. Sandomire says not only do these keep the homes cooler but they’re also attractive architectural features.
Emphasize Indoor Air Quality
While residents of Kumuhau might prefer to be outside all the time, that isn’t always feasible. Therefore, a healthy indoor-air environment was as important as easy access to the outdoors, so Armstrong Builders made sure to use healthful paints and finishes.
The Kumuhau Subdivision puts Hawaii’s tropical climate to good use by collecting rainwater for outdoor, nonpotable use. Residents are able to save on utility costs by using the rainwater for rinsing off, for plants, and as a reservoir for drip irrigation. The small footprint tucks it out of the way, and the high water level allows for better water pressure in each of the homes.