Builder Doug Mcdonald is the speaker for the Wilton Go Green/Wilton Library Green Speaker Series on Sunday, Nov. 18 at 4:30, when he talks about the first retrofit Passivhaus in the country. Doug will share his knowledge and insight as the owner of this energy-efficient house in Westport that was redesigned with energy savings in mind. Attendees will learn about passive solar gain, energy recovery ventilators and how Doug’s family members use their own body heat to keep the house at 73 degrees, using 90% less energy than a traditional home. This talk is co-sponsored by Wilton Go Green, Neighbor to Neighbor and the library. There is no charge. A reception follows the talk. Registration is recommended.