Your AC consists of an air filter without which it cannot and should not be running. Let’s look at some potential problems that you can run into if your AC is running without a airfilter whether it is a ducted or ductless air conditioner.

How Does Your AC Air Filters Work?

Before we begin discussing what would happen to your AC if it is running without a filter, it is important that you understand how AC filters work. The AC air filter is designed to block dirt, dust, and debris from entering your AC system as well as your house. Your air conditioner sucks in air from the outside, strips the heat from the air, and then blows it back inside the home. This is where the AC filter comes in. Its job is to prevent dust and debris from getting sucked into your HVAC system along with the air.

If, in case, you do not have the AC filter in place, the dust and debris will make it inside your house. In the long run, not only will the dust and debris accumulate in your house but inside the HVAC unit as well. As a result, your home’s air quality will drop significantly and can also damage your home’s AC system.

Decrease In Home’s Air Quality

The first disadvantage of running your AC without a filter is the decrease in the air quality of your house as mentioned earlier. While this may not bother you temporarily but in the long run, it can lead to serious health problems, especially if you have people living in the house with asthma-related problems. Furthermore, your kids getting exposed to the constant dirt and debris can negatively affect their health as well. Therefore, it is important that you should keep your AC air filter clean. Although you should clean it at least once a month but depending on the area where you live, it might be that you need to clean it multiple times a month.

Frozen Evaporator Coils

If your AC is running without an air filter, chances are that the dust and debris sucked into your indoor AC will settle on the system called the evaporator coils. Evaporator coils tend to be filled with a refrigerant that enables them to absorb heat from your home’s air. If you happen to find dust on the evaporator coils, you should know that it will not be able to absorb much heat from your home as it is causing the coils to freeze.

Once you have determined that your evaporator coils are frozen, you might run into issues like increased energy bills, damaged compressors, or less conditioned air. You will want to avoid each of these situations. In the case of your evaporator coils being covered with dust, they will not be able to perform at their optimum and therefore, the AC unit will have to work harder to cool the area. Hence, the increase in the energy bills. So, for an efficient air conditioning, never run an AC without an air filter.

On the other hand, if the AC unit keeps running while the evaporator coils are frozen, you might end up damaging the compressor. Often referred to as the heart of the system, it is responsible for pumping the refrigerant through your AC system. And since your AC will not work without the compressor, replacing it is necessary and is going to cost a couple of hundred dollars. Therefore, make sure that you install the air filter and keep it clean.


AC’s are designed to cycle regularly while they are running. If you have a dirty air filter installed or nothing to keep the dirt and dust out, your AC will short-cycle more than it should throughout the day. This will not only cause noise pollution but will waste energy and lead to uncomfortable temperature changes as well.

Allergen Buildup

Your AC having no air filter installed is going to lead to allergen buildup. This can be a serious problem if you have people with asthma or respiratory allergies in your house. The allergens will build up inside your HVAC system and will flow inside your house along with the air as well.

If you AC is having issues, get the help of an HVAC repair service Woodbury to fix the issue quickly and safely.