A solar heating system for mounting under a roof includes a panel formed of a sheet material, the panel having substantially opposed first and second surfaces and adapted for attachment under the roof with the first surface substantially facing the roof. A plurality of tubing fasteners extend outward from the second surface of the panel, and at least one run of tubing is held against the second surface of the panel by the plurality of tubing fasteners. The plurality of tubing fasteners can be partially cut-out and bent portions of the sheet material. The system can also include a sidewall formed by folding a portion of the sheet material toward the second surface along a line of weakness and standoff tabs extending from the first surface formed as partially cut-out and bent portions of the sheet material.