It's never a good idea to operate your air conditioner or HVAC system without an air filter in place. Without a filter, the condensate drain will not be able to drain moisture from the air conditioning unit, resulting in condensation building up in the Freon tube and dripping down the tray. This can cause water damage to the entire system. Additionally, running the air conditioner without a filter is worse than running it with a dirty one, as it can lead to poor indoor air quality and increased symptoms of allergy, respiratory problems, eye irritation, or irritation of the nose and throat.
The air conditioner blows cold air into your home, but it also expels dust and other particles that are trapped inside your HVAC system. If you don't have a filter, more dirt will enter your home and recirculate, leading to shortness of breath or an increase in allergy symptoms. Mold spores will also circulate throughout the house as long as the HVAC system is working, causing health problems for you and your family. Air filters are generally good at filtering out dander, but operating the air conditioner without a filter poses an additional risk of damage to the mechanical components of your HVAC system and the health of your pets.
Poor air quality due to pollution, excess dirt, or mold can also cause faster damage to HVAC systems. If you don't know where to look or what type of filter you need, it's best to let an experienced HVAC technician do the work for you. Although they are only one component of your HVAC system, your filters serve an especially important purpose. Running the air conditioner at any time without an air cleaner is not recommended because of the permanent damage it can cause to the HVAC system.