I am not noticing any variation of fan speed with my 2001 inbuilt heater. There is no variation of air flow ..From low or max' setting. This heater is not performing like the demo model we saw at the supplier show room. I feel there is a fault with the 2nd speed not coming on and I am only getting the excuses from the supplier. There is supposed to be a noticeable variation between fan speeds isn't there???. From an unsatisfied customer.