Green Sand wins a BIA Award in two very different categories showcasing their expertise across project platforms.
Hale Kalawahine won in the Sustainable Energy Residential category as an example of doing renovations right.
The Hale Kalawahine project submitted is a renovation of an existing circa 1939 home. The primary project goal was to improve the indoor environment quality of the home, specifically thermal quality. The home became very hot in the early afternoon and by mid afternoon the second floor was unusable until well after sunset. The owner’s primary goal for the renovation was to cool the house so that it was comfortable year round, all day long and most importantly, without the addition of air conditioning. The owner’s established the following secondary goals to be done simultaneously during construction: modernize the kitchen, replace the roof and expand the lanai. The final goal was a net zero energy home.
The 1939 home was built with single wall construction and had an un-insulated poorly ventilated attic space. Although the original cedar shingle roof on skip sheathing may have allowed the attic to breath when it was installed, this ventilation had been blocked when the original roof was covered with metal shingles sometime during the 1970’s in a poorly executed reroofing effort. The interior of the home was also dark requiring light fixtures to be used during the day, adding even more heat into an already hot environment. The southwest facing façade was unprotected and unshaded with the afternoon sun beating into the family room through a large fixed picture window.
The first strategy was to improve the thermal comfort of the home by addressing the roof and attic condition. This was done through insulation and ventilation. The existing roofing was removed down to the skip sheathing and replaced with cedar shingle roofing installed over Techshield, a radiant barrier. The attic space was insulated with R30 batt insulation installed at the attic floor. The number and area of eave vents were doubled and roof vents were added near the ridge of the roof. The final strategy was the installation of a whole house fan that pulls cooler air from the lower parts of the home and pushed out hot air from the attic.
The second strategy was to increase the ventilation through the upper level of the home. A dormer facing the trade winds was installed to catch the wind and direct it through the home. Additional windows and a sliding door were added at the kitchen. The whole house fan also aided in pulling cooler air through the home.
The third strategy was to mitigate the heat gain through the southwest facing façade of the home both for the upper and lower levels. This was accomplished through a covered lanai across the entire southwest façade. The lanai provided shade for the master bedroom below and the roof over the lanai provides shade for the family room and parlor.
Other strategies contributing to a comfortable indoor environment include:
· Solatubes and additional windows in the kitchen reduce the need for using lights during the day.
· Solatube in the powder room further reduce the need for using lights during the day.
· New double wall construction was insulated with R15 batt insulation.
· The lights in the ceiling/attic are all ICAT rated to reduce heat transfer from the attic to the interior space. · Natural materials were used when feasible.
· Low VOC materials such as paints, coatings, sealants, and adhesives were also utilized.
Lastly, energy is produced on-site by a photovoltaic system with a goal of providing 100% of the existing electrical load through net metering with HECO. The PV system was the last piece of the puzzle after appropriate strategies regarding natural ventilation and daylighting were implemented to avoid the need for an AC system and reduce the energy load. A right-sized PV system was purchased to offset the remainder of the electrical load of the home.
This project is a stellar example of a highly sustainable project meeting the very intent of the GreenBuilt standard:
1. Renovation of an existing home or “reuse of existing building” saves the embodied energy of the existing materials, labor, and transportation for the original building.
2. Eliminate the need for mechanical air conditioning systems saves the resources required to manufacture, transport, and install and AC system. In addition, on-going energy and carbon footprint savings resulting the use of natural ventilation vs. mechanical ventilation.
3. Reduce the need for using lights during the day, saves energy use and the resulting carbon footprint.
4. Produce a significant amount of the electricity needed on-site contributing to the States achievement for the 2030 goal regarding energy independence.
5. Day lighting and views have been demonstrated to support a productive and healthy lifestyle.
6. Natural ventilation helps contribute to a healthy indoor environmental quality.
7. Right sized PV system after reducing the electrical load through proper design.
The design aesthetic sought to honor the character and feeling of the original 1936 home. A simple shaker style detailing was used through out. New doors and windows matched the horizontal mullion pattern of the original window system. White Carrera stone was selected for the countertops and backsplashes. Stained oak flooring was selected throughout. The entire interior and exterior was repainted with a subtle soft palette of colors. It is worth noting that ever effort was made to keep the original wood flooring throughout, however, the wood floor had been worn and previously sanded and resurfaced to such an extent that the original wood floor had to be replaced with a similar solid wood flooring. It was an unfortunate but necessary decision but also indicates that a life span of 77 years for solid wood flooring makes solid wood flooring a good durable choice.