If you don't change the AC filter, it can lead to a range of problems. You won't be able to filter the air properly, allowing dust and contaminants to enter the air conditioner. This will clog up moving parts, such as motors and fan valves, and restrict airflow. This will cause your HVAC system to work harder, using more energy and costing you more money.
Not changing the air filter can also lead to poor indoor air quality, with immediate problems such as headaches, itchy eyes or throat, and dizziness. In the long-term, it can even lead to respiratory disease, heart disease, or cancer. A clogged air filter can also cause the air blower to break down, which in turn causes the entire HVAC system to break down. It can also damage your HVAC system and reduce its life expectancy. The best source of information on how often to change air filters is in the HVAC system owner's manual.
However, there are times when your HVAC will show warning signs that filters need to be changed. During peak summer or winter months, you should change the HVAC filter more often. Putting a filter that is too small for your HVAC can be harmful because it will allow dirt and dust to enter your unit. Homeowners who ignore filters in their heating and air conditioning systems risk increasing energy costs, damaging expensive equipment, and decreasing indoor air quality and personal health. Getting the most value out of your home can be as easy as changing air filters. I always change my filters every 30 days and recommend the same to my customers: the EPA recommends at least inspecting their filter every month.
This simple maintenance element can save you from a lot of trouble in the long run.