Olive House: Prefabricated and Passive
A healthy, energy efficient home that can serve as testament to the importance of Passive House Institute U.S. standards
By Yvonne Nguyen
Disillusioned by the overpriced real estate market in Brooklyn, Alessandro Ronfini, designer at DEMO Architects and his wife decided to invest in land and build their family home. As a result, Rofini purchased a 11-acre plot in Olivebridge, New York, at the southern edge of the Catskills and designed the Olive Passive House.
Nestled among a pond, a stream and a mix of evergreen trees, is a modern home that was built with comfort and sustainability in mind. The 3-bedroom house was certified by the Passive House Institute U.S. (PHIUS) following completion in 2021.
Owned and designed by Alessandro Ronfini, the project was created to prove that homes can be comfortable and contemporary while still meeting rigorous Passive House standards.
Ronfini is a designer at DEMO Architects, a team of Brooklyn-based Certified Passive House Designers who create healthy, comfortable and energy-efficient homes that not only improve the lives of the occupants, but also the environment.
In partnership with Threshold Builders, Ronfini was able to create a healthy, energy efficient home that can serve as testament to the importance of implementing PHIUS standards in new homes.
The Olive house is pre-designed, prefabricated and assembled onsite over a concrete foundation. Threshold Builders, who are known for building prefabricated, Net Zero and Passive Houses, offer three home designs inspired by Scandinavian farmhouses with open living space and super high-efficiency design.
The compact design made the engineering and construction streamlined and efficient. Aside from the roof, the entire building envelope is a panelized system built by Threshold Builders in a shop miles away from the jobsite, helping not only to cut down on product waste, but also in reducing carbon emissions from the distance traveled.
The system is composed of a 2×4 structural frame, with Zip Board as an interior air barrier, then packed densely with insulation in between TJI outriggers. Windows and doors were taped with airtight tape to create a seal.
The Olive Passive House is sustainable in all aspects, not just in the way it was built. The house consumes 80% less energy than a traditional house of a similar size. It is a fully electric house with energy efficient features such as a compressor stashed under a balcony, a floor mounted mini split unit that provides heating and air conditioning and a tankless electric water heater.
With such beautiful natural surroundings, Rofini had to get strategic with his design to maximize views of the pond and their natural surroundings while still maintaining his privacy with his neighbors. As such, the house is oriented 30 degrees southeast to secure a view of the pond and still get natural light from the sun exposure towards the south. The house is designed to optimize view, light and privacy.
At only 1,500 square feet, the small size of the house made it difficult to meet the PHIUS requirements, even though the designer and builders set out to build a Passive House from the start. The construction of the Olive Passive House ensures that residents are living in an environment that is insulated and protected from outside weather, with high performance ventilation and improved air quality.
Passive House design is a comprehensive approach that accounts for every detail of a house, down to heat emissions from appliances and occupants. It involves designing specifically to attain a rigorous level of energy efficiency while also maintaining comfort and livability. The core concepts of the PHIUS standards include thermal control, air control, radiation control and moisture control. 
The team was able to create a residence that is both energy efficient and cost effective with clever design strategies, high quality construction materials and the integration of high performance features including mini split heat pumps, electric water heaters and solar panels.
In addition to achieving Passive House standards, the project has also earned recognition as a Zero Energy Ready house, alongside ENERGY STAR for homes and EPA Indoor airPLUS certifications. Olive Passive House is a recipient of the PHIUS’ Best Project by a Young Professional award in 2021.
“The process took much more time than expected and many more tools than anticipated but eventually in the late spring of 2021, the house was completed, it achieved Passive House certification and it finally started to get filled with the [our] furniture, friends and growing family,” said Rofini.
Yvonne Nguyen is the Assistant Editor of Green Home Builder. She can be reached at yvonne@builder.media.