Designs that maximize sunlight exposure and utilize materials that store heat are great ways to use passive solar heating in a greenhouse. Position the greenhouse with its longest side facing south to capture as much sunlight as possible during the day. Use clear or translucent materials for the roof and walls, such as polycarbonate or polyethylene, to allow sunlight to penetrate. To store heat, incorporate thermal mass, such as water barrels, stone, or concrete, inside the greenhouse.
These materials absorb heat during the day and slowly release it at night, helping to regulate temperature fluctuations. The greenhouse should also be insulated, especially at night, to prevent heat loss. Using double or triple glazing for windows, sealing gaps, and greenhouse covers at nighttime ensures that warm air stays inside. You can enhance passive solar heating by adding overhangs or shading devices that protect against overheating on sunny days, allowing for better temperature control.
