Indoor air quality problems are more likely to occur if you use your air conditioner without a filter for an extended time. Allergic reactions, breathing problems, eye discomfort, and nose and throat inflammation are possible side effects. If you don't have a filter in your air conditioning system, it is suggested that you don't use it because it can cause serious harm to your system and require expensive repairs. air conditioning repair McKinney can help you understand the working of an AC filter.