Furnace filters are an integral part on a HVAC unit. If changed properly your furnace or air conditioner will give you years of trouble free operation, but if you neglect it you could have some serious problems in store for you. If you do not change your furnace filter at the manufactures recommended service interval you put a higher load on the furnace blower motor. Also when you are running your heat the lower air flow causes the This can causes it to operate at a higher temperature and can cause it to overheat and stop working, which can be very costly. It is wise to check your furnace filter at least monthly to see if there is a considerable amount of dirt and dust buildup. If the furnace filter looks light gray on the media it must be changed.
On average a filter needs to be change at least every 3 months. If you run your air conditioner in the summer or live in an area where you must run your furnace in the winter it would be recommended to change your filter monthly. Thicker furnace filters such as an 5" Honeywell furnace filters can last up to 6 months for changes, but should be checked monthly. If your furnace is in your garage or attic be very sure you check your furnace filter monthly as there is a much higher chance of contamination due to leaks in your duck work. Leaks in your duct work can pull dust and debris into the furnace and plug the furnace filter faster. Be sure to have a qualified professional check your duct work for leaks as this can save you time and money.
Higher MERV furnace filters such as a MERV 12 can help reduce the amount of debris and dust that gets past the filter that can plug the air conditioner coil. If your air conditioner coil gets dirt built up it can cause the blower to work harder or worse can cause coil rupture and failure. Also changing your filter often can save you up to 15% on your electric bill because your furnace is working at peak efficiency. Ask yourself this. Would you rather let your furnace filter get dirty or have a costly repair bill? If you answer change your furnace filter you are wise. With the minimal cost to replace the furnace filter you are in a sense saving yourself money.