Hi, thanks for your post. The Dyson humidifier is designed to push moisture into the air and the purifier is designed to take particles out of the air. Water, even in vapor form, can contain micro particles of naturally occurring minerals which the purifier cannot distinguish from a dust particle. This can also result in a poor air quality reading. This being said, the purifier will run for longer to remove these additional particles from the air. Which could reduce your filter's lifespan. For this reason, we recommend the use of distilled water (which contains far less minerals) in your Humidifier if it is in the same room as the Purifier.