The new Cantherm Jumbo heaters are highly portable and offer many ducting options for almost any application. These indirect-fired heaters are rated for 460,000 to 600,000 BTU, pumping out between 4700 and 6100 cubic feet per minute of dry, heated air. They feature a unique two-stage start up, and can be operated as a fan only, drawing air as far as 100 feet into unventilated areas. Cantherm Distributors. 800-661-9276.