A protective cover for a solar panel. The cover provides protection for the solar panel from the elements of the weather such as snow, hail, sleet, and windblown debris, and also against overheating of the solar panel during periods of long and intense solar radiation, when the demand for hot water is insufficient to dissipate heat build-up. The cover is constructed of material having heat-insulative properties and provides a barrier layer over the top of the solar panel to reduce the amount of heat transferred to the water tubes.