With no phase control, I would use a 2-pole 480VAC contactor with a 24VAC coil, small 24VAC control transformer, open-on-rise thermostat for the work space, and a fixed temperature, bi-metallic temperature switch for the heater enclosure surface.
With no phase control, that contactor will be banging on and off like crazy! 16 KW for bench heating seems to be a bit excessive. A PID temperature controller would make more sense for moderating versus a bang-bang control scheme. If it is grossly oversized, why not operate it on 277 or 240 if available? Less output, longer cycle times.
