When I visit the local hardware store to purchase a new air conditioning system filter for my air conditioning system unit, I find that there really is no shortage of filters to choose from. However, I do not know besides of what my Heating, Ventilation plus A/C provider recommended, what air condition system filter is acceptable or which one is not. Beyond me. Does that choice really it matter? All air conditioning system filters are the same right? Except for size, of course. The filter has to fit, that much is obvious. Anything beyond that, knowing which is the best air conditioning system filter escapes me, so I conducted air filter research and found that the cheapest air conditioning system filters on the market are not the best to buy. This did not surprise me at all, but what was surprising is that the cheapest air conditioning system filters are not rated to pull out mold spores, dander, pollen and other harmful agents plus the cheap filters are so thin that I could see through them. I would guess that the purpose of the air conditioning system filter was to keep from going through unknowingly through our Heating, Ventilation plus A/C systems. This concerns me and I think that those identifiable air conditioning system filters should be pulled from the market to be kept away from unsuspecting consumers. The air handler is a virtual breeding ground for bacteria, mold plus other things to form, negatively affecting numerous people often children and the elderly. After this research I vowed will change my air filter yearly leaving me with the option of which air conditioning system filter am I going to use.