These little heaters (I bought 2)... DID work great  -- until they started making some loud noises, followed by the fanblower of the heater not working and a harsh electrical smell started.  Then TONS of black smoke! As if the fan quit or jammed...then blew the motor.  Very scary because it didnt stop even after shutting it off.  Had to unplug. Luckily I was nearby when it happened. 
A week later, the 2nd one did the same noise -- not going to plug that one in anymore either.  These heaters were only used when my college kids would come home for breaks.  Not used all the time.