A recirculated heated air mat system melts snow and ice from driveways or roofs, preventing its accumulation. The driveway sized, hollow mat of tough, pliable rubber, plastic is resistant to tearing and abrasion. A recirculating air electric heater provides heated air to the mat. The mat contains baffles directing heated air sinuously through the substantial portion of the mat, and an internal wall forms a cooled air return path along the upper end for recirculating the air to the heater. For a two-car garage, two pads are provided. The second pad may be identical to the first pad. Heated air is directed between the first and second mats and returned through the cooled air return path by separate removable ducts between heating air paths and cooled air return paths. The system may be modular, being assembled from identical mats and ducts. A large single mat for a roof is provided.