South-oriented, triple-thick polycarbonate glazing. Instead of glass we use a plastic material called polycarbonate. It lasts approximately ten years before it begins to yellow. It is triple thick which allows for two insulating air spaces. Dead air space insulates and slows the cooling of the structure as well as helps to keep it cooler in summer. The glazing faces south at an optimal 45° angle. It is strong and is resistant to both hail and fire.
Thermal mass. The daytime sun heats the water-filled fiberglass tubes and 55 gallon metal drums. The containers are located along the north and south walls. The containers heat up to about 70° in the summer and 60° in the winter but will never feel warm to the touch because our body temperature is 98.6° and our skin temperature is usually warmer than the water. These water-filled containers give-off heat because the night/day difference in temperature is great enough to cause the warmer heat from the containers to radiate into the colder greenhouse. In summer they help to keep the greenhouse cooler because they are shaded most of the day.
Insulation. Both the east and west walls as well as the north roof are heavily insulated. The perimeter of the foundation exterior is also insulated into the earth with a two-inch sheet of Styrofoam along the outside of the concrete foundation to a depth of two feet. This insulates the ground inside the greenhouse from the cold ground outside the greenhouse during winter.
Weatherized structure. All windows, doors, fans and vents are well weather-stripped to prevent leaks and cold drafts.
Optimal angle for sun. During the summer, the sun is higher in the sky and the water-filled tubes and drums are in shadow which helps cool our greenhouse.
During the winter, the sun is lower in the sky. It shines directly into our greenhouse illuminating and warming the water filled tubes and drums which heats our greenhouse.
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