This helped me with seasonal allergies. I keep the system on low due to two reasons, 1) on auto-mode the machine cycles too frequently between the highest mode and lowest mode and 2) power consumption is fairly high when the machine is blasting. On the lowest mode, the sound is low enough that it can be ignored. It's to the point where you even have to question if it's on. Anything higher and it is noticeable. Don't worry if the machine seems to run on high for a long time before cycling down to low. I noticed after one month of regular use that the amount of dust on the pre-filter was significant. I had to clean this twice and have the machine running for quite a bit before it was convince that the air in my home was clean. The machine is pricey but I do think it was worth the purchase. for best use, keep it running as long as possible each day.