When people hear “change your furnace filter” they think that it only needs to be changed in the winter months. Actually if you have central air then your furnace blower is most likely running year around and needs to be changed often. A furnace filter should be changed between every 1-3 months depending on a few things. First don’t get caught up in the label on the filter that says the filter is a three month filter, six month filter, year filter ect. If you are using your blower motor on your furnace for both, heating and cooling your home then it needs to be changed more often. A home without pets, or children and is always being swept and dusted can get away with changing their filter every three months. Mind you I am not talking about the cheap fiberglass filters that you can see through. Those are only 20% efficient. This meaning 80% of the dust goes through the filter to be either recirculated throughout the house or gets stuck in the cooling a-coil creating a larger problem for the cooling side of the operation. It is better to use a pleated filter that is not too thick. Thicker is definitely not better. Thick will restrict the air flow going though your furnace causing major problems on both the heating and cooling side. It can also destroy your furnace by cracking the heat ex-changer causing the deadly carbon monoxide to be distributed in your home to breath. I recommend a pleated furnace filter that the price ranges from $3-$6 dollars. They usually are just thick enough to take out the dust and allow the air to flow easily through it. A home that has pets, has smokers, children stirring up dust and may not have time to always be on top of the dusting and sweeping should change their filter at least once a month regardless what the packaging states. I hope this helps everyone on when to change the furnace filter and what to buy that is best for your furnace and your family.