What's not to like about housing that incorporates great design, energy efficiency, and a small footprint (carbon and otherwise)? We're big fans of prefab, green housing here at Re-Nest, so when a reader sent us the tip to check out Cottage in a Day, we couldn't resist. And with the largest one's price tag hovering around the "affordable" zone, we knew they merited a show-and-tell. According to their site's FAQs, the cottages "dramatically exceed the National Association of Homebuilders green standards." Jump below for links.The architect's site shows many different facets of the cottages, widely available in Michigan. The company is based in Michigan, but according to the FAQ on the Cottages in a Day site, they can ship one of these to you after a plan review is passed in accordance with your state's policies.