Abstract: A structure and method of solar energy collection use a building roof acting as a heat collector, conductor, and convector passing thermal energy to air in a volume below. The air may stratify according to temperature, with flow controls maximizing temperatures by operating dampers, valves, or both in the air and a liquid working fluid, respectively. A finned heat exchanger may be a hydronic baseboard-type heating unit operating to transfer heat in the opposite direction, into water inside the central pipe. A thermo-mechanical actuator, such as a wax motor may provide passive control, and heat may be collected in an open circuit of culinary water, a closed loop, or a double loop system. Ducting aids stratification, temperature maximization, and heat exchange to enforce pre-selected temperatures in the air and water working fluids.