They are actually pretty quiet. The only thing I was surprised about was how fast they ran out. It only sprays for around 10 seconds and that's it. I think the scent is just so fine that it lingers in the air and carries for a great distance. Although, it does dispense the same amount of scent that is in an entire bottle of tinks 69. However, as far as I'm concerned, if they work as good as I have seen first hand and heard from other reliable sources I'll be getting a few more.