I bought this for my mom who suffers with breathing difficulties and this has helped. Once you have added the water and oil you can walk around the house worry free as the product shuts of automatically when the water runs out. However after a month of constant use at night this has now become rather noisy and you can hear the motor whirring louder every time you use it. so no longer good for usage in the night but it still works.
I would have rated it 5 if it wasn't for the noise issue.