Old and dirty air filters in an air conditioner will have a negative impact on the performance of the system, causing it to cool ineffectively and affect the quality of air inside the room or house.
According to the American Council for an Energy Efficient Economy, cleaning the air filters on a monthly basis will help to increase the energy efficiency of a room air conditioner.
I searched Lowes, Home Depot and other retails for my air filter with unusual, size and had no luck. A friend recommends me Total Filters, and was surprised to find them with free, shipping, and now my air conditioner is running much better with this supply of fresh, high quality filters.
Love these filters, works great in eliminating the dust in the air. My order of 12 comes nicely packaged and on time. I can tell the difference in the air quality since I put this filter in. My allergies are much calmer.