My mouth literally dropped open when I first saw this air purifier. It is a first class, quiet, powerful air purifier that only uses 10 watts on its HIGHEST fan speed – a fraction of a low wattage light bulb. This is an air purifier that you can afford to keep going, day and night, without running up your electric bill – and for people like me that is important. I regard this as an astonishing feat of ecological engineering. No air purifier, let alone one with a fan is so energy miserly. It would not be worth a hill of beans if it wasn’t the highest performing air purifier that Blueair has ever manufactured. What’s more, its filters can be vacuumed to prolong its life. The entire Blueair ECO10 unit is recyclable; including the polypropylene HEPASilent filters which can be vacuumed to prolong their life. Can’t say enough good things about this machine, and I firmly believe it is worth the extra price. It got a 5-star rating from me and I do not give that out often.