LEED represents green building leadership and is transforming the way we think about designing and constructing buildings that save money and resources and have a positive impact on the health of the occupants, while promoting renewable, clean energy.
Our Kayenta Staff Quarters Design-Build project for Indian Health Service is a world-class green building community and an excellent case study of a better way to design and build. We were given the target of LEED Silver for this project by the federal government but because of the innovative housing prototype our team developed this project is now on track for LEED Gold and Platinum.
The key to our innovative super insulated shell is found in the construction of the exterior building envelope system. All exterior walls are built with a 2X6 wall, leaving an inch gap to eliminate thermal bridging. Then an additional 2X4 wall is added. This results in a 10" thick double exterior wall system that gets filled with expandable spray foam insulation. This insulation also gets applied to the underside of the roof decking which creates an air-tight super-insulated building shell.
All interior space from the roof down is within this shell and creates an extremely energy efficient dwelling. It's like living inside of a thermos; it keeps the warm air in during the winter months and thus greatly reduces the amount of energy required to maintain a conditioned air space.
Having an air-tight building is excellent for reducing energy use but it is not an ideal condition for healthy indoor air quality. The solution to this is to utilize and ERV (Energy Recovery Ventilator) which is a mechanical ventilation system that filters incoming outside air and saves energy.
Since our buildings are air-tight, all air (other than the dryer vents) that comes in and out of the building gets circulated through the ERV.
The hot water in these homes is heated by the sun with the use of a solar thermal panels on the roof which circulates to the water heater.
We also use the sun to heat the homes by running the hot water generated from the solar thermal panels through the coils of the furnace to heat the air. This innovation further increases the energy efficiency and lowers the utility bill of the residents.
All 129 homes in this community use 100% non-potable water for landscape irrigation. We developed one-of-a-kind greywater harvesting system that utilizes the used water from washing machines. Instead of just sending it to the sewer this water is sent to planting beds to irrigate trees and shrubbery.