Engine idle + car standing still + low fan speed+radio on, fan is not noticeable. With radio off, can hear slight noise. Anything above 1st speed is noticeable even with radio on. I only use 2nd speed to more rapidly cool or heat the interior and then go down to 1st speed once comfortable and this can usually maintain comfortable interior. There is no noticeable motor whine at any speed, but would probably be drowned out by the noise of air thru the vents.