4 Signs Your AC Air Filters May Be Clogged

Posted on: 20 August 2021


Air filters are some of the most significant components of an air conditioning system. They trap and hold pollutants and particulates in the air like pollen, dust and dirt, animal fur, hair, fibres and lint, mould, mould spores and wood particles, among many others. Such particulates could be harmful to your health if left to circulate throughout your home. However, with continued use, the air filters become clogged with these particulates. When this happens, you must clean the filters or replace them. Failing to do this will affect the efficiency of your air conditioning system. Therefore, watch out for these signs that your AC air filters may be clogged.

Airflow Issues

Airflow issues are among the most common indicators of clogged air filters. You will notice reduced airflow when your air filters start becoming clogged. Generally, your air conditioner's blower fans push air through the air filters. If the filters are clogged, the blower fans will struggle to push air through. Therefore, if you are not getting as much air airflow from the vents, chances are your air filters are the culprit.

Clogged air filters are often accompanied by inconsistent temperatures. That means you may start noticing cold and hot spots in the room. Your energy bill may also increase as the AC struggles to cool your home. If you don't clean or replace the filters, you may end up with burnt-out blower fans.

Insufficient Cooling

Clogged air filters also come with cooling inefficiencies. If your home isn't cooling as usual, consider checking your filters for clogs. Dirty air filters prevent the cooled air from passing through properly, leaving you with air that isn't cold enough.

Frozen Coils

Dirty air filters can also cause your evaporator coils to freeze. Therefore, inspect your cooling or evaporator coils for ice build-up if you start noticing cooling inefficiencies. As your air filters become clogged, they hinder proper airflow to your air conditioner's cooling or evaporator coils. Generally, the cooling process causes condensation, which without proper airflow, quickly freezes on the coils. It's crucial to fix the problem early enough because frost build-up on your evaporator and cooling coils will strain your air conditioning system, leaving you with high energy bills. In worst cases, the AC will break down completely.


Clogged filters make your system work harder than usual. Therefore, the strain can easily cause overheating. If the back of your AC unit becomes too hot, chances are the filters are the culprit. Your unit may also start blowing hot air, a sign that it's overheating from too much strain. Check the filters and clean or replace them as necessary.