A vacuum cleaner manufacturer was telling us the other day on how to sell their vacuum cleaners. Our staff sat around with open mouths as he told us that they label their hepa filters “replace on such and such a date 12 months from now” while these filters may not need changing for ten years. But hepa filters are consumables and good business. We were all mighty uncomfortable with this conversation. So when does a hepa filter need replacing? It is like your furnace filter – if you can see through it (the light test) it is still absorbing particulates. Hepa filter media is white, so when it is far from white – change it. Now, NOT changing it will mean very little air will come out of your machine and the motor can burn out. So, be warned – change them when they need to be changed, but do not waste your money unnecessarily. Of course, some manufacturers make it so difficult to get at the filters; it is a special project to even inspect them.