Replacing your air filters frequently is an important part of keeping your home healthy. Depending on the type of filters you buy, these can often catch dirt, dust, pollen, pet dander, and even smoke. Forgetting to replace these filters causes the air in the home to be unhealthy, it can cause discolorations in carpets and walls, and it makes your units work harder than they need which makes them more susceptible to wear out quicker and leads to increased energy costs.
Modern air conditioning systems usually have a grille installed in a wall or ceiling usually close to the thermostat. Behind this grille is where the air conditioning filter is located which is easily unlocked with finger clamps.
Once you open the grille, you can take out the old filter. Make sure you replace it with the exact same size that fits the opening. Pay special attention to the side of the filter where there will usually be an arrow point in the direction the air should flow. Since this is a return air, the air is being sucked into the grille, through the filter and then through a duct.
Watch this quick video from ExpertVillage that shows you how easy it is.