Abstract: A proofing or heating cabinet is provided having an enclosure with an interior and a pair of oppositely disposed side walls forming elongate heat ducts therein; the heat ducts having openings in their mutually facing surfaces. A modular heating assembly is removably disposed in the enclosure and has aligned end openings communicating with the heat ducts. Placed within the modular heating assembly at one end opening thereof is an electric heating element extending substantially thereacross, and at the other end thereof a blower device substantially extending thereacross to maintain generally laminar the airflow through the modular assembly.