Downtown Columbus will welcome its newest tenant, DesignGroup, and celebrate the completion of the area's most efficient new-build in 2000 later this month when the leading architectural, design and planning firm officially opens for business at its new headquarters at 515 E. Main St.

The five-story, 62,000-square-foot loft-style office building, which incorporates cutting-edge passive solar architecture for ultimate energy efficiency and features "honest" architectural expression, is a joint project of DesignGroup and Schmidt Enterprises.

DesignGroup will occupy the third and fourth floors of the building. Schmidt Enterprises, which has revitalized other properties in the East Main Street area, will occupy 3,000 square feet.

Designed by DesignGroup's Jack Hedge, a leading passive solar architect, the $7.2 million building, called One Market Exchange, is a hallmark of sustainable design and energy efficiency. Its passive solar orientation and day lighting features – sun screens on the south elevation that screen out undesirable summer heat gain and soak in desirable winter sun for heat and light; large windows on the north side that maximize day lighting with minimal heat gain; and a third- and fourth-floor central atrium with a south facing clerestory to allow natural light to illuminate the central area of the building – save 10 percent to 18 percent in energy use.