The project:
Homeowners Ellen and Rich faced a challenge familiar to many: balancing the demands of two properties while seeking a simplified, affordable and enjoyable living situation. Their primary residence was in New York’s Hudson Valley, but they also owned a property in Mystic, Connecticut, which they used for weekend getaways and short-term rentals. To streamline their lifestyle and better manage their rental property, Ellen and Rich explored building an accessory dwelling unit (ADU) on their Mystic property and moving there permanently.
After careful research and zoning approval, Ellen and Rich chose Unity Homes, a recognized leader in high-performance homes, to make their vision a reality. The Unity team determined the project was a perfect candidate to experiment with innovative building methods and materials. Ellen and Rich were fully on board with this approach, as they appreciated the focus on energy use and comfort.
The goals were to design and build Ellen and Rich’s dream ADU, while optimizing home energy-efficiency and construct a building enclosure that would stand up to any extreme weather conditions over the long haul. To measure the long-term performance of the home, a network of 50+ sensors would be embedded in the home to measure key building performance indicators. The sensors will measure temperature, humidity, energy use and carbon dioxide in the home, as well as inside the actual walls and roof of the building enclosure.
Challenges:
High-performance, high-design construction poses new challenges, in particular to speed and design fidelity. The Mystic ADU project came with those key challenges, close neighbors which the team did not want to disturb, and the added challenge of building a high-performance home in a small footprint. A less known fact is that the smaller the home, the less wiggle-room there is for mistakes in building performance - every detail counts more.
Additionally, the pandemic created significant delays in production timelines, leading to a backlog that threatened the project's schedule.
Achieving the balance of speed, beautiful design and top-notch results within a budget reasonable for an ADU would be a major challenge in traditional construction. Instead, Unity collaborated with CertainTeed on an innovative approach to panelized offsite construction to meet all the project’s goals.
The Solution:
Unity Homes partnered with CertainTeed, using CertainTeed’s ONE PRECISION ASSEMBLIES™— a prefabricated building system designed to enable exact building performance specifications and much shorter construction times. The innovative system enables builders to complete high-quality, weather-tight homes in a fraction of the time, without compromising on durability or aesthetics.
ONE PRECISION ASSEMBLIES offers factory-built, insulated and sealed wall, floor and roof panels. Backed by decades of building science research, the precision-engineered panels control water, air, moisture and thermal energy, while eliminating any guess-work in product specification or detailing.
ONE PRECISION ASSEMBLIES are sealed and manufactured with incredible accuracy—within 1/16th of an inch—to ensure a perfect fit on-site. This process minimizes errors, material waste and costly delays caused by weather or other external factors.
Key Benefits of the One Precision Assemblies include:
- Weather-Tight Construction: The panels feature sealed air and vapor control layers, achieving Passivhaus-level air-tightness (0.6 ACH50), ensuring the home remains energy-efficient and protected from the elements.
- Hygrothermal Control: Utilizing WUFI® hygrothermal analysis, the system ensures that the assemblies are free from excess moisture, preventing mold growth and structural degradation over time.
- Exceeding Code Requirements: Designed to surpass 2018 IECC thermal performance standards, the panels provide superior energy efficiency, reduced heating and cooling costs and the size of the HVAC system itself.
- Design Flexibility: Customization is a core feature, with the ability to adapt panels to different home specifications and support a range of American and European window and door brands.
- Reduced Waste: Software optimizes material usage, cutting down on excess waste and making the construction process more sustainable.
- Simplified Construction and Warranty: ONE PRECISION ASSEMBLIES™ comes with a single specification and a warranty that covers the entire building envelope, streamlining the process and reducing risk for both builder and homeowner.
- Accelerated Build Time: The system drastically reduces the overall construction timeline, allowing homes to be built in days rather than months, cutting building cycles by up to 50%.
“As a professional with 20 years in energy efficient construction, working with CertainTeed's ONE PRECISION ASSEMBLIES is bringing a fresh approach to simplifying home construction,” said Unity Homes Project Manager Beth Campbell. “The efficiency of the process significantly streamlines construction, and the pre-engineered energy efficiency features help us achieve a high-performance home with minimal additional effort. I am excited to have gotten in on the ground floor of such an innovative and ingenious product and fully expect industry-wide adoption of the ONE PRECISION ASSEMBLIES system within a few years. It's just that logical.”
Results:
The Mystic ADU project was completed with remarkable efficiency. In just a few days, the entire ONE PRECISION ASSEMBLIES system was assembled on the property, with one single day dedicated to testing and ensuring airtightness for the building enclosure.
From the outset, embedded sensors began collecting real-time data on key performance metrics such as temperature, humidity, energy usage and interior air quality. The results have consistently proven that precision-driven construction delivers superior performance. Notably, actual hygrothermal conditions within the home met or exceeded the initial WUFI simulation models, affirming the precision and quality of the ONE PRECISION ASSEMBLIES system.
These findings are invaluable for ongoing improvements in residential construction. Both Unity Homes and CertainTeed are leveraging this data to refine their processes and further enhance their high-performance building designs.
"The Mystic pilot home is a clear example of how thoughtful design paired with advanced building science and automation can address the evolving challenges of modern home construction," said CertainTeed Platforms Senior Research Engineer Evan Molony. "We are committed to using this data to continuously validate and optimize our approach."
The success of this project not only met the homeowners’ goals, but also provided critical insights into the future of panelized, prefabricated construction. The project timeline was streamlined, while maintaining a high standard for quality. The ONE PRECISION ASSEMBLIES system offers builders a unique opportunity to deliver aesthetically pleasing, energy-efficient and sustainable homes faster, with fewer on-site complications.
Ellen and Rich’s new home in Mystic stands as a testament to what is possible when modern construction techniques and innovative materials come together. They now enjoy a low-maintenance, high-performance home that reflects both their vision and the possibilities of the future. As Ellen put it, "We absolutely love our home and wouldn’t change a thing. Having never worked with a prefab, sustainable home building company before, we didn’t know what to expect. The craftsmanship exceeded our expectations."
The success of this ADU project paves the way for wider adoption of precision panelized systems, heralding a new era of efficient, high-quality residential construction.