Many residential air conditioners use disposable filters, which you remove and replace every couple of months. However, if you have a more intensive air filtration system attached to your furnace, or if you are trying to eliminate as many allergens from your air as possible, you may have a more robust, reusable filter in your system. This filter will last for at least a few years, but you will have to clean it periodically to ensure it does not get too clogged or stop doing its job. To do so, just follow these instructions.
Step 1: Remove the filter.
If you're not sure where the filter is in your air conditioning system, look in your owner's manual. It should have a diagram that points out the location of the filter. If you cannot find your manual, you'll have to do some looking around. The most common place to find an AC filter is right between the blower unit and the main air duct. Note that if you have a complete HVAC setup with a furnace and AC unit, the filter may appear to be between the furnace and the duct. This is because the blower is found in the lower portion of your furnace.
Step 2: Vacuum off the dust.
Take a second to turn off your air conditioning before you remove the filter. You don't want it to kick on when there's no filter in the system and blow dust through your home. Then, slide the filter out of place. Use the wand attachment on your vacuum to remove any dust from both sides of the filter. Make sure you don't press too firmly against the filter material; you don't want to bend or dent it.
Step 3: Rinse it off.
Now it's time to remove the finer material that the vacuum did not capture. Run the filter under warm water. If you notice dust that's getting stuck, you can gently rub it away with a sift brush -- like an old toothbrush. Do not vigorously scrub the filter as you may damage it. When you're done rinsing shake the filter off. Let it air dry for 5 or 10 minutes. It's okay if it's still a bit moist, but you do not want it dripping wet. Slide it back into the filter slot, turn your AC back on, and go about your day. Remember to clean your filter again in one to two months.
Contact a contractor, like Miller Services HVAC Inc., for more help.