One winter night, when the temperature was 10-below zero, Duluth architect Carly Coulson hiked into the woods to watch the northern lights. “It was so tranquil and beautiful,” she recalls, “but I longed for a small retreat, with no impact on the environment, where I could insinuate myself into nature and sit and watch the sky.”
She went home and sketched that retreat. Then, using her expertise with advanced energy modeling and Passive House strategies, she designed the simple modern structure to live lightly on the land. By using triple-pane glass, super insulation, passive solar heating, summer shading, and heat recovery ventilation, Coulson eliminated heating and cooling mechanical systems. She calls the structure Disappear Retreat because of its glassy transparency, fluid connection to the landscape, and zero energy use. She calls the process she used to design it “invisible sustainability.” Both have taken the Internet by storm, with articles in publications from Dwell to TreeHugger to Daily Mail.
The Waconia native worked at Foster + Partners in London and Salmela Architect in Duluth before starting her own Duluth firm, COULSON, in 2009. Today the firm is building the Disappear Retreat and designing custom models for clients, as well as designing MH House, a near-zero-energy suite of glass residential and office pavilions next to Lake Superior in Duluth. We talked with Coulson about the explosion of interest in Disappear Retreat, balancing the technical and aesthetic aspects of her work, and how Minnesota’s unique climate drives design innovation.
Why has Disappear Retreat attracted so much attention?
It’s become a catalyst for talking about sustainability in a way people can understand, while attracting diverse audiences. No matter how terrific a building is at reducing energy use, just discussing building science only reaches a certain audience. Disappear Retreat also shows that sustainability is sexy. My style tends to be quiet, so the building sits quietly in its context with the landscape as its focus. There’s a magic and beauty not only in its aesthetic, but also in its construction and simple operation. That has engaged the imaginations of people interested in nature and the environment, fashion and art, architecture and design, technology and high-performance buildings. To shift the public perspective on sustainable design, architects have to excite all of those groups.
Tell us more about what you mean by invisible sustainability.
Buildings are, of course, not invisible. But our approach is based on a simple less-is-more approach, in which the sustainable elements are seamlessly integrated. Since 2008, all of my work has met the Passive House Standard, a system for energy efficiency created in Germany that focuses on the building enclosure. Advanced energy modeling is an essential element in our creative process. We put variables like temperature, sunlight, and shading into the software to discover “what would happen if we do this?” Then we integrate air tightness and materials like super insulation and triple-pane glass into the design to achieve lightness and transparency. These low-tech integrated solutions alone can achieve a 70- to 80-percent energy reduction. Other green-building approaches rely on high-tech systems or gadgets that create visual and operational complexity, and impact the poetry of place. Our simple approach is disciplined and experimental, liberating and exciting, with a great degree of invisibility.
Could Disappear Retreat be built anywhere else?
Our North identity includes our strong connection to climate: We understand what -40 feels like and what it costs to heat our homes. That identity also includes our love of and appreciation for nature, which we want to protect. Those are both essential elements in what we’re doing. In the process, we’re upending old assumptions about what sustainable design looks like in cold climates—and we’re just scratching the surface. I’ve been asked to design a similar structure for a location in California, but that would be something different altogether as designing for climate is critical to our approach