A pellet burner has inner and outer housings for defining a high pressure air plenum between. Angled perforations at strategic locations in the inner housing supplied pressurized primary and secondary combustion air so that, with pellets supplied to a burn pot of the inner housing and activation of a blower and an ignitor cartridge, the pellets auto-ignite and the air flow establishes a swirling flame in the burn pot that travels to a flame conduit of the inner housing where further swirling occurs in a venture section for shaping the flame into a clean, hot, symmetrical form.