Clean air is a necessity for physical and mental health. Today, many people cannot get enough fresh air because they have to live and work in closed environments. Especially in single-volume heating or cooling, the indoor air is reconditioned several times, and the air regresses to an insufficient level of air quality over time. The users can only overcome the situation by simply opening the windows and getting fresh air but unfiltered and unconditioned air. In this study, a fresh air supping unit was developed for split air conditioners to create healthier and more comfortable living environments. For the selection of the fan in the fresh air intake module, the amount of fresh air needed in the living room according to the ASHRAE standarts, the ability to change the fan speed, and the ability to overcome pressure drop caused by hose and filter were evaluated. In addition, a filter group was utilized in the unit against particles that may come from the outside environment. The prototype of the designed unit was produced and tested in terms of temperature and performance. The obtained results were investigated in detail.