The Edge House

Rodwin Architecture imagines a contemporary residence on the cutting edge of sustainable design

“Architecture is typically defined and inspired by its constraints,” says Scott Rodwin, principal of Rodwin Architecture in Boulder, Colorado. “It’s an architect’s job to find the most graceful, intelligent and efficient way to respond to those constraints.”

So it was most unusual when a new client app-roached Rodwin not with a list of do’s and don’ts, but with one simple directive: “design a home that’s as green as you can make it, and do the very best job possible.”

So began the process of designing a LEED Platinum-certified, near-net-zero-energy home in Boulder that uses about the same amount of energy as it produces over the course of a year. The home includes a 10-kilowatt photovoltaic system, a solar-thermal system and ground-source heat pump, as well as passive-solar design, a super-insulated thermal envelope, high-performance fiberglass windows, and a palette of building materials low in VOCs and completely free of formaldehyde.

But it’s the features you won’t yet find on a LEED-certification checklist that make this project so notable: pioneering methods and materials that will change the way tomorrow’s sustainable homes are built, from the city of Boulder’s first legal gray-water system, to an experimental three-part insulation technique that achieved super-insulated walls with an R value of 38—exterior walls typically have an R value of about 19—an R-20 slab and an R-65 roof, with no thermal breaks.

Before Rodwin and his team could implement this cutting-edge design, the site’s existing 43-year-old, 7,000-square-foot home had to be addressed. “The house was a disaster,” Rodwin recalls. “It had six floors and was filled with asbestos and shag carpeting from top to bottom. There weren’t any windows on the south side, and almost none on the western side, which is where the view is. And it was built over the property line on two sides, right down to the foundation. We quickly determined that it was unsalvageable.”

The amount of material that comes from an old house—and that usually goes to the landfill—is staggering, and until recently, it has cost significantly more to salvage those materials than to send them to the landfill. But this project changed that. Rodwin’s team helped to introduce a new method of accounting to Boulder County that gives homeowners the replacement value of deconstructed materials rather than the resale value. This change, which adds up to a much better tax benefit, allowed 91 percent of the old home’s materials to be deconstructed and salvaged at virtually no additional net cost to the homeowner.

With the existing house removed, Rodwin and his team turned their attention to ensuring that the new structure would function optimally. “When net-zero energy is the goal, you have to start employing some extraordinary measures,” Rodwin says. “When you combine a 10-kilowatt photovoltaic system with a ground-source heat pump and throw in solar-hot-water panels, you have the opportunity to cut your energy bills to nearly zero.”

What’s most remarkable about this array of high-tech systems is that the house can actually recognize the most efficient means of heating or cooling itself at any given time—and use that particular method. As a result, the house has achieved a Home Energy Rating System (HERS) index of 6, which means it uses 94 percent less energy than the HERS Reference Home, which has an index of 100 (based on the 2006 International Energy Conservation Code).

“Our goal was to get as close to net-zero energy as possible,” says Rodwin. “That meant passive solar design was critical. The trick was doing that while still opening to the huge western view.” This sort of give-and-take, the thoughtful balancing of form and function, is what makes this home as appealing to its owners as it is sustainable. “Throughout the design process,” says Rodwin, “we looked at both architecture and energy systems and found the point of convergence.”

A WATER LEGACY

When the homeowner requested a gray-water system and was told it wasn’t allowed, he and Rodwin Architecture worked with the city to change the building code and create Boulder’s first legal gray-water system. The homeowner not only installed a prototype in his house but started a company called Water Legacy, which makes these sustainable ­systems available to the public. 

How does it work?  The Water Legacy gray-water system collects used bathing water from baths and showers, then filters and disinfects it using hydrogen peroxide and ultraviolet light. The clean water is then stored and supplies filtered water to toilets on demand.
How much water does it save?  The average household will save approximately 12,000 gallons of water each year.
Is it easily installed?  Because the system requires gray water to be separated from black water, it’s best suited for new construction and serious remodels; retrofits can be challenging and costly.
What does it cost? A new Water Legacy system costs an average of $3,000, while the additional required piping typically costs less than $500.

ARCHITECTURE Scott Rodwin, Rodwin Architecture, Boulder, CO, 303-413-8556, rodwinarch.com INTERIOR DESIGN Eiko Okura, Okura Interior Design & Feng Shui, Denver, CO, 303-777-5135, eikookura.com GENERAL CONTRACTOR Jason Staver, Sigg-Staver Construction, Berthoud, CO, 303-944-2085 MECHANICAL ENGINEER Liz Gehring, Gehring & Associates, Architectural Engineers, Boulder, CO, 303-449-7266, thearchitectsengineer.com STRUCTURAL ENGINEER Julian Lineham, Studio NYL, Boulder, CO, 303-558-3145, studionyl.com GEOTECHNICAL ENGINEER Chip Leadbetter, CTL Thompson, Fort Collins, CO, 970-206-9455, ctlt.com DECONSTRUCTION Russ Callas, Haul Away Recycling, Boulder, CO, 303-931-7398, haulawayrecycling.com JOBSITE RECYCLING Bryce Isaacson, Western Disposal, Boulder, CO 303-444-2037, westerndisposal.com GEOTHERMAL SYSTEM Jim Richmond, Radiance Corporation, Nederland, CO, 303-517-8640, coloradoco.com RADIANT FLOOR HEATING & SOLAR THERMAL SYSTEM Pete Evangelista, Stout Mechanical, Ward, CO, 303-459-3423, stoutmechanical.com GRAY WATER SYSTEM Mike Vail, Water Legacy, Denver, CO, 303-587-9147, waterlegacy.comPHOTOVOLTAIC SYSTEM Jim Welsh, Bella Energy, Boulder, CO, 303-552-7468, bellaenergy.com MASONRY Paul Gonzalez Jr. Masonry, Boulder, CO, 303-818-0332 TIN WORK (Ducts) Mike Hildebrandt, Cooper Heating, Broomfield, CO, 303-466-4209, coopergreenteam.com CABINETRY Margie McCulloch, Red Pepper Kitchen + Bath, Boulder, CO, 303-413-9400, redpepdesign.com HOME AUTOMATION Keith Pharris, Ambient Systems, Boulder, CO 303-447-6807 ELEVATOR Brandon Hunt, Morning Star Elevator, Colorado Springs, CO, 303-623-7433, mselevator.com