A heating and cooling system for an enclosure includes a positionable solar panel assembly that supplies power to all the power consuming components of the system. A mountable sun tracking assembly continuously detects the position of the sun and adjusts the position of the solar panels to follow the movement of the sun during the day and to reposition the solar panels in the evening to receive the morning sun the following day. One or more ventilation assemblies mountable in one or more openings in the enclosure controllably supplies heated or cooled air into the enclosure, evacuating inside air, re-circulating inside air, and/or circulating outside air in response to control signals from the sun tracking assembly. A control box mounted inside the enclosure selectively controls operation and testing of the system. A dome is provided as an aesthetic covering for the ventilation assembly.