Jury: “The jury viewed this project as an environmental learning center because it has so many of those characteristics. … There were a number of that building type in the running, and yet this one really delivered on the promise that we were looking for. Genuine performance with a beautiful elegant design.”

Architect: “The project proves that you don’t have to sacrifice design for sustainability. We used the Passiv Haus standard because its criteria were so high and it paid off with a better building. We emphasized the sustainable features to strengthen the architectural statement, so the sustainable elements are what make it dynamic and architecturally significant.” —David Salmela, FAIA, David Salmela Architect

Located in a 55-acre nature reserve, the University Classroom building at the University of Minnesota Duluth (UMD) needed to have a small environmental footprint, and minimize site disturbance, water run-off, and energy use. To start, David Salmela Architect chose to work with previously developed land and an existing parking lot at the Northwest edge of UMD, which is within walking distance of campus. As a result, building occupants can use existing campus parking, negating the need for new lots. The building, which is used by eight departments at UMD, was minimized to 1,995 gross square feet and incorporates an outdoor classroom with a fireplace, wood storage area, and recycled cedar benches, all in order to reduce the overall square footage of the structure while incorporating the surrounding reserve as a teaching tool.

In addition to striving for (and achieving) LEED Platinum certification, the design team incorporated Passive Haus strategies to minimize energy loads. The building is oriented to take advantage of passive heating and cooling and eliminate artificial cooling, and requires 78 percent less energy use due to optimal orientation. It takes only 3,000 watts (the equivalent of three hair dryers) to heat the building on the coldest day of the year.

To the south, pre-existing deciduous trees provide shade in the summer. On the south, east, and west wises of the building, glazing was calculated with Passiv Haus energy modeling software to optimize passive solar gains in the winter and prevent overheating in the summer. Grid-connected photovoltaic panels on the low south roof generate up to 8,500 kWh in a cloudy year. The building uses the sun as its primary heating source, and any supplementary heat is provided by an electric heat coil at the ventilation system. An electric boiler and in-floor radiant heating system serves as a backup heat system, and small, on-demand, tankless electric water heaters are used to heat water at two hand-rinsing sinks.

Sixteen inches of insulation on the walls and roof as well as 12 inches of 100-percent-recycled-content SPA insulation around the foundation and under a concrete floor slab reduce the heating load, as does a system of structurally insulated panels (SIPs) that features continuous insulation and no thermal breaks. Married with these elements are triple-pane glass windows with insulated frames and insulated doors with wooden frames.

In the winter, the windows are closed and locked to prevent heat loss. Due to the building’s air tightness, mechanical ventilation provides constant fresh air. In warmer months, operable windows on the lower east and west façades and venting louvers on the higher east and west façades take advantage of site wind to create 100 percent natural ventilation through a stack effect via upper ventilation louvers in warmer months. A heat-recovery ventilation system removes 85 percent of the heat from exhausting air to minimize heat loss. The system is turned off each night and the building is flushed out each morning to remove pollutants from the air.

All habitable rooms in the building have exterior views and daylight is further augmented by solar tubes in the ceilings. Wood horizontal screen covers the windows to prevent bird collisions and provide shade from solar gain in the summer.

A two-level vegetated roof planted with drought-tolerant sedum that can survive up to four weeks without rainfall and doesn’t require irrigation. The upper roof holds 90 percent of rainfall on the building and drains into a lower vegetated roof to delay stormwater runoff, an important element as the site drains into a nearby watershed that includes a protected trout stream. To further aid in stormwater management, the building is surrounded by an underground trench drain system that gathers runoff from walkways and holds the water in the site’s forested area where it can be infiltrated by daylight. Two composting, vacuum-flush toilets provide minimal waste water for the sewer system, directing most waste to two central composting tanks. A mop sink and the two hand-washing stations are equipped with sensor-controlled, low-flow fixture faucets.

Further influencing campus operations, the UMD facilities department managed and executed the building’s construction with in-house staff, training the crew in efficient construction practices and training them for future university construction projects.

Building gross floor area: 1,995 square feet
Estimated percent of occupants using public transit, cycling, or walking: 72
Percent of daylight at levels that allow lights to be off during daylight hours: 100
Percent of views to the outdoors: 100
Percent of spaces within 15 feet of an operable window: 48
Percent reduction of regulated potable water: 87
Is potable water used for irrigation: No
Percent of rainwater from maximum anticipated 24-hour, two-year storm event that can be managed onsite: 100
Total EUI (kBtu per square foot per year): 36
Net EUI (kBtu per square foot per year): 27
Percent reduction from national average EUI for building type: 78
LEED rating: Platinum
Total project cost at time of completion, land excluded: $1 million

Data and project information provided by architecture firm via AIA COTE Top Ten entry documents.

For an extended view into David Salmela's philsophies on sustainable design as well as a showcase of the firm's other green projects, click here. For more information on each project, as well as a database of past Top Ten projects, visit aiatopten.org.