Most Efficient Greenhouse Designs

Insulated Walls and Foundations

• Insulation is of paramount importance in order to build an efficient greenhouse. A freestanding greenhouse should have the north wall insulated. If the greenhouse is placed in a sunny area, the east or west walls should be insulated. An insulating material called Reflectix, which is basically bubble-wrap that has a foil backing is often used. It can be found in hardware stores or in greenhouse catalogs. Greenhouse foundations should also be insulated by placing a foot of Styrofoam around the foundations.

Glazing or Greenhouse Skin

• An energy-efficient greenhouse design ensures that the glazing or greenhouse panels through which the sun shines is doubled or tripled. The glazing should also be dust-free and sealed thoroughly so that the heat cannot escape. Older greenhouses can be retrofitted with new glazing or the inner panels can be covered over with vinyl.

Sealing and Ventilation

• In order for the greenhouse to work at maximum efficiency, every nook and crack must be checked, caulked and sealed by the end of fall. All doors need to be weather-stripped. Vents and doors must checked for leaks and then weather-stripped. Good air circulation, conversely, even in winter is important. Some efficient greenhouses are equipped with high roof vents that allow airflow but prevent gusts of wind from entering the structure.

Thermal Heat and Greenhouse Entry

• Piling rocks around the base of a greenhouse can help to store heat from the sun. This can also be done using water that is stored in black drums and placed around the exterior of the structure. A two-door entryway into the greenhouse ensures that plants don't get frozen with a blast of cold air each time the door is opened. A two-door system also saves on energy.