Abstract: This invention pertains to an improved thermal slab assembly. A metal slab defines an exterior surface of the assembly and is supported on a hollow chassis. A plurality of thermoelectric devices are conductively engaged with the underside of the slab and are disposed in a regular array relative to each other, whereby each device is assigned a respective one of a corresponding plurality of equal area portions of the slab. Control means are coupled between the slab and the thermoelectric devices for sensing the temperature of the slab and for regulating operation of the devices to establish and maintain a predetermined temperature of the slab. A vertically and parallelly finned heat sink is conductively coupled to each thermoelectric device.