In this Well+Good article, John gives valuable advice on the mechanics of window air conditioners.

Air conditioners can play a significant role in good indoor air quality. Greater asthma morbidity – specifically a larger number of hospitalizations, wheezing episodes and night symptoms due to asthma – have been associated with the presence of moisture, mildew and cockroach allergen in homes. Air conditioners provide a dual function of controlling temperature and relative humidity in home environments, as well as potential removal of allergens.