The Colorado Renewable Energy Society (CRES) and the Colorado Energy Science Center (CESC) sponsored a lecture by green building experts at the National Renewable Energy Laboratory (NREL). Architect Thomas Doerr presented to a sold out audience of over 100 attendees about the essentials of passive solar design. Topics included proper building orientation, area and type of glass, solar shading, thermal mass, ventilation, room arrangement, daylighting, and other important ecological building strategies.