Passive House Institute US (PHIUS) is a 501(c)3 organization committed to making high-performance passive building principles the mainstream best building practice, and the mainstream market energy performance standard.
Passive building comprises a set of design principles used to attain a quantifiable and rigorous level of energy efficiency within a specific quantifiable comfort level. “Maximize your gains, minimize your losses” summarize the approach. To that end, a passive building is designed and built in accordance with these five building-science principles:
- It employs continuous insulation through its entire envelope without any thermal bridging.
- The building envelope is extremely airtight, preventing infiltration of outside air and loss of conditioned air.
- It employs high-performance windows (typically triple-paned) and doors
- It uses some form of balanced heat- and moisture-recovery ventilation and uses a minimal space conditioning system.
- Solar gain is managed to exploit the sun’s energy for heating purposes and to minimize it in cooling seasons.
Passive building principles can be applied to all building typologies–from single-family homes to apartment building to offices and skyscrapers.
Passive design strategy carefully models and balances a comprehensive set of factors including heat emissions from appliances and occupants–to keep the building at comfortable and consistent indoor temperatures throughout the heating and cooling seasons. As a result, passive buildings offer tremendous long -term benefits in addition to energy efficiency:
- Superinsulation and airtight construction provides unmatched comfort and even in extreme conditions.
- Continuous mechanical ventilation of fresh filtered air assures excellent air quality.
- A comprehensive systems approach to modeling, design and construction produces extremely resilient buildings.
- Passive building is the best path to Net Zero and Net Positive buildings because it minimizes the load that renewables are required to provide.
This particular house, built for Lucien Ellison, owner of The Ellison Building Company and his family, is the first Passive House built in Southeastern North Carolina, and only the second to be built in a “hot-humid” climate (2012). Special considerations and modifications needed to be made to the Passive House analytics program to ensure the house could be built to standards properly. Experienced, knowledgeable consultants and craftsmen we hired based on their expertise and commitment to make this unconventional method of design and construction a reality.
In addition to the rigors of the Passive House program, the owners were very interested in creating a home in a mid-century modernistic styling. They also were convinced it would be wise to build the house of concrete. Concrete would ensure the house would be here for a long time, minimize maintenance, and contribute to the aesthetic desired.
The main structure of the house was built with precast concrete panels with integrated foam insulation. The panels were manufactured in Chapel Hill, NC by Ideal Precast Inc. and shipped over land to Wilmington, NC and erected in less than two weeks. The entire shell of the house was completed is a very short time, enabling efforts and time to be concentrated on the rigorous detailing of the Passive House program.
The design of the house itself was approached as a landscape concept, one in which the integration of a series of ancient live-oak trees were to be preserved, and integrated into the design, as well as to exploit the subtle topography through the implementation of a split-level design. Maximizing the views of Hewlett’s Creek and idealizing solar orientation while preserving the trees was the greatest challenge. The result is a home that is truly in harmony with nature and its surroundings. At over 6,000 square feet under roof, the home still appears to be nestled into its environment, very unassuming, almost camouflaged among the oaks.
A unique, butterfly roof form maximizes solar gain in winter months, and channels water into a trough, where collected for irrigation purposes. Polished concrete floors, a massive exposed steel truss, and exposed wooden beams and ceilings contribute to the minimalistic styling with an organic relief.