101 Series: Continuous Insulation (10/4, 12pm ET / 9am PT)
April 13, 2022

Net Zero Energy Home in Fairfax

Net Zero Energy Home in Fairfax

The Conner Home in Fairfax Virginia is both an architectural and environmental gem and Sto Corp. played an important role in providing solutions to achieve both distinctions. Most notably, the residence is the very first net zero energy home in the city, which means it uses energy efficiency and the production of its own renewable energy to produce an energy bill that is “net zero.”  

While David Peabody of Peabody Architects had envisioned a home that relied on  mineral wool batts and high pressure laminate panels to achieve the desired aesthetic, the subcontractor with whom he was working expressed concern about the material choice. They said unreasonable installation costs made the approach a non-starter.


The solution was StoTherm® ci Lotusan®, which is an exterior insulation and finish system (EIF) with a super-hydrophobic finish that was developed based on the practice of biomimicry. By learning from the strategies that nature developed, Sto was able to create an exterior finish that sheds water from the surface much like the leaves of the lotus plant, reducing maintenance costs by extending cleaning and re-coating cycles. This all-in-one building envelope system is ideal for projects such as the Conner home which are designed according to Passive House principles. “The ‘Aha!’ moment for me was when I realized if we use StoTherm® ci, we don’t have to separately air seal the walls of the house,” said Peabody. After application of the StoGuard® liquid-applied air and moisture barrier, which is part of the StoTherm ci system, an air infiltration number of .45 ACH@50 pascals was achieved.

In addition to making the process of air sealing the home easier, Peabody was also won over because he was going to need a significant amount of insulation to reach the level of energy efficiency the project demanded. According to Peabody, this was another built-in advantage of the StoTherm ci system. “You can adjust the insulation value without adjusting the stud width,” he said, which meant he was able to avoid double stud construction and reduce costs on materials and labor.


Peabody was also attracted to the color and texture choices offered within the StoTherm ci system along with its ability to create sharp, clean panel divisions were not available from other finishing systems. Application subcontractor Robert A Aird, Inc., who was very familiar with Sto from previous jobs, used a hard-troweled approach with StoLit Lotusan 1.0 to achieve the final texture. “We wanted a clean industrial look,” Peabody said when describing the aesthetic vision that he and the homeowners shared. “We saved considerable money doing it this way and still got a very smooth and crisp finish.”

The finished house is a triumph of Passive House design, both aesthetically and practically. The modern styling speaks for itself on the design front. As for energy efficiency, the home is so well insulated and sealed so tightly, that its 20-kW solar array generates enough energy to not only power the entire house but also an electric vehicle and a hot tub! The homeowners themselves are certainly pleased with the results: “We appreciated the greatly lower cost of EIFS compared to the alternatives. We still had sharp corners and lines.”

It would be difficult to find a more effective use of EIFS anywhere. The EIFS Industry Members Association obviously agreed, awarding the Conner Residence a 2019 EIMA Hero Award, which recognizes outstanding projects in the EIFS industry. That’s a lot of buzz for a house that requires so little energy!


The only limit is your imagination

Inspiration favors the open mind. With Sto, your creative exploration can take you anywhere. Our proven products give you unmatched freedom and the ability to achieve your vision in any color, any form, any texture, any material.

Combining innovative design and high-level performance, StoTherm ci offers a unique approach to wall system installation. These fully engineered systems provide unmatched versatility with an array of design options that include unique textures, colors, shapes and materials to suit any creative vision. With StoTherm ci, you get innovative products, forward-thinking design, and durable performance that surpasses your expectations. Rest assured, Sto is there wherever your inspiration leads.

Creativity Begins. Sto Finishes.®

Sto Corp.

Sto Corp.

Sto Corp. is an international company selling Passive House wall systems, coatings and finishes.

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