Passive solar homes in the north east is beginning to be studied in research and development by some residential engineers and builders. These homes require a high R factor to walls, roof and windows; wall 40-50 R factor, roof 70-85 R factor, windows 15 or greater R factor. There are many other design factors to an off grid green habitat.
For domestic hot water the GSE IP-195 Passive Thermal Solar Collector is incorporated into passive solar home construction and is also ideal for incorporating into convential homes and hot water heaters. These passive solar collectors simply are operated by well pump or city water pressure. Since the collector is designed for heating domestic hot water use, R Factor to a habitat's space heating is irrelevant and since domestic hot water is used everyday in the home, the solar system is utilized 365 days a year. The conventional utility used presently heating hot water makes no difference.