Works very well for inhaling essential oils

Works very well for inhaling essential oils  Read Less

This is no low hum, if I had to compare it to something I would say it sounds like a motor vibrating against wood, and the high...  Read More

This is no low hum, if I had to compare it to something I would say it sounds like a motor vibrating against wood, and the higher the setting the faster and louder the sound gets. The first time I used this I had a cold and was diffusing some oils (eucalyptus, tea tree, lavender and peppermint) to help clear it out so I couldn't turn it off. Eventually I did get used to the sound and managed to tune it out, but that makes it even more noticeable to me when it turns off because of the sudden absence of noise.As happens when your nose adjusts to scents I couldn't noticeably smell the oils in the room anymore after using it for a few days but if I left the room and reentered later I could smell them again even when the unit wasn't on, so the oil fragrances do linger.If the manufacturer was to make any kind of improvements to the unit I would suggest some kind of sound dampener in the base cavity (I know the vibration itself is necessary for the diffusion process) or improving it if it exists as I suspect the mechanism inside (whatever it is) is vibrating against the wood base and the exact placement inside could cause a variation in noise level unit to unit. So maybe it's nearly soundless for some or a low hum as some have described but in mine it's very noticeable.Still I'm overall happy with it and glad I didn't get one of the diffusers with the lights (I don't like lights in my room when sleeping). It's attractive, I like that replacement globes and tops can be gotten if something happens to the glass parts and it sits stable on my shelf, it gets a 4 out 5 stars due to the noise.  Read Less