Insulated solar panels that provide a solar thermal collector with means for limiting stagnation temperatures and preventing damage include: temperature limiting is provided by the insulated solar panel, isolating internal components from the environment, using passive closed systems within the sealed solar thermal collector, while also allowing alternative implementations as active systems and/or portions of the temperature limiting system outside the sealed solar thermal collector. A heat pipe can be used as a passive thermal switch, where the temperature induced action at a predetermined temperature causes an abrupt transition from a state of thermal isolation to a state of strong thermal coupling. Additionally, a set of siphon circulation pipes provides a passive closed system for temperature limiting.