If the quality is correct, I stay on my hunger for space and especially perfectible design, fashion bottle warmer, which is not very discreet in a room. I discovered meantime other more aesthetic models (more square, approaching a stereo camera, much more rounded, so essential oil diffuser).
The filter must be changed once a year, but to avoid premature fouling, it is best to position the device, slightly elevated for the preservation of soil dust.
In summary, an effective apparatus (the nanocloud technology ensures mastered broadcast) to any design for those looking for great simplicity.