(MONEY Magazine) – "Honey, the house has arrived." Welcome to the new world of prefabs, where floor plans, chosen online, are delivered by truck as fully built houses four months later. Some 80,000 homes a year are now built completely off-site. Only a handful, however, boast a modern aesthetic. Among them is the Glidehouse, the first environmentally friendly prefab, designed by architect Michelle Kaufmann, 35, after she and her husband spent six unsuccessful months hunting for an affordable house in the Bay Area that matched their green politics. One- to four-bedroom Glidehouses cost a low $120 a square foot, plus $6 to $15 a square foot for shipping. (The price does not include the foundation or land costs.) Kaufmann's houses offer such earth-loving features as floors cut from bamboo ("You're not killing trees that can't be grown quickly," she says), concrete countertops that contain recycled paper and ash, and low-VOC paints (as in, volatile organic compounds) that are considered healthier for the lungs.

Kaufmann, who sold her first home this past spring and has another two dozen under contract, says the three-bedroom prototype that she and her husband built in Sausalito, Calif. costs nothing to power and heat. That's because they put in a $20,000 solar-energy system, which also raised the appraised value of their home by $40,000, she says. Folks who prefer to rely on their local gas or electric company can still expect savings of up to 50% a year, thanks to energy-smart designs that maximize natural light and cross-ventilation. Details at mkarchitecture.com. --J.C.