In one of my eco-bio classes the professor - a true hippie from the 60s - had photos of his house. He built a greenhouse to butt up against his back door so essentially his back door just went straight into the greenhouse - it was all of recycled plexiglass from the university and wood from an old barn a tornado had gotten to - anyway, he let rain water fill 55 gallon drums for watering and then would save them all up in late fall when everything was dying and kept them in the green house - the green house would heat up from the sun, heat the water and then he could just open his back door at night and the heat from the water-filled drums would help to heat his house. come spring he had enough water to start watering plants again.
