Yale Architecture Thinks Big, Goes Small

by Eric Ellman

Yale College students don’t expect the tiny solar home they’ve designed for the upcoming U.S. Department of Energy Solar Decathlon to win the nationwide event. They know the contest favors larger schools with bigger engineering programs and a history of competition. Their goal is loftier. In the course of pushing the competition’s “small is beautiful” ethic to the limit, team Y-House is challenging orthodox prescriptions for sustainability in an effort to persuade the Department of Energy to reconsider contest rules.

The Solar Decathlon format is straightforward enough: Design and build a solar home with a footprint less than 1000 sq. ft. that generates enough power for all of its occupants’ needs.  Then tear it down, ship and reassemble it in Irvine, California next October to be judged on ten criteria, from architectural design and affordability, to performance on a gauntlet of domestic challenges: drying laundry to its pre-wash weight, charging an electric car to complete a 25-mile commute, and hosting dinner parties and a movie night for fellow competitors during a week and a half of open house showings for the public.

During the competition, thousands of visitors will troop through the seventeen competing homes, each one an elegantly persuasive argument for energy-efficient, compact design. With household energy needs accounting for almost half of our nation’s energy consumption, the spectacle confronts a disturbing trend. As Team Y-House co-captain Pablo Ponce deLeon ’16, explains, “since the 1950s, American families have gotten smaller while homes have nearly doubled in size.”

Y-House bucks that trend more than most. With a contest minimum surface area of 600 sq ft, its footprint will be little more than half the size of most competitors.  Practically speaking, that reduces cross-country shipping costs.  Conceptually it fits a vision of multiple yHomes comprising a “Y-Community” of shared exterior space. Yale University Facilities Manager Julie Paquette, who shared a trailer park with fellow students during graduate school, inspired that concept.  “She helped us realize that small spaces – with what some considered sub-optimal standards – could actually forge a superior community,” says Ponce deLeon.

Y-House architecture reflects more contrarian thinking.  “Most Solar Decathlon homes represent Passivhaus design,” says co-captain Kate McMillan ’16, referring to an ultra-high efficiency certification carried by tens of thousands of (mostly European) homes.  Small, highly insulated homes make sense for this competition, she says, because mechanical systems can easily control temperature and humidity within ranges that the contest rules demand. 

“But outside space is just as important as the house itself,” she says.  Adjusting a shade, or moving a mobile barrier to briefly turn an outdoor space into an indoor one can achieve the same comfort level, save energy and subtly encourage occupants to better note and enjoy Irvine’s Mediterranean climate.  Plus, less hermetically sealed space means less chance of trapping gas or mold that contribute to “sick house” syndrome.

Such bedrock architectural sensibilities, and nuts-and-bolts innovations guiding yHouse design come straight out of “Solar Decathlon 2232a,” a course that Hines Professor of Sustainable Architecture Michelle Addington developed when the Y-House proposal was picked by DOE to go forward last fall. The class assures that decathletes meet face-to-face weekly and receive at least three credits for the thousands of student hours that designing and constructing the building take.  Leveraging her diverse experiences as an engineer and materials scientist for both NASA and DuPont, Addington introduces students to ideas at the forefront of architecture and physics, even if they lack congruity with the ten events in which the design competes.

Consider lighting.  Contest rules award maximum points for homes that continuously burn all lights with dimmers set to maximum.  While that tests a home’s ability to continuously generate power, it doesn’t reflect what is known about the eye.  Good visibility requires contrast more than illumination, Addington says, an understanding that suggests an entirely different approach to lighting.  Illuminating workplace surfaces rather than the entire workspace, or using materials with different textures to heighten contrast, reduces glare and power requirements with no loss of functionality.  Since lighting represents up to half of a commercial building’s electricity use, the concept is supremely important, but not reflected in DOE contest rules.

Addington’s ideas about comfort may be more disruptive yet. In an Architecture Boston interview she says “I’d never live in an insulated house.”  Better to maintain an ambient temperature of 50 degrees, and condition other areas as needed using vertical surfaces to radiate heat, she suggests.  “We have chilled ceilings, we have heated floors, but those are not radiant systems,” she explains.  “Those end up operating by convection and create incredibly homogeneous environments.”

If that homogenous condition is household-wide, requires cooling or heating, and is fundamentally unnecessary, that’s an energy travesty, suggests Addington.  But it’s a travesty that the contest encourages; the “comfort zone” contest deducts points for failure to maintain constant temperature and specified humidity throughout the home. 

So be it.  For Team Y-House, victory in the solar decathlon would be seeing future contests embrace designs that incorporate new knowledge of human physiology. A great alternative, says McMillan, would be the People’s Choice Award, “given to the home where everyone wants to hang out.”