Window air conditioners typically use R-410A (also known as Puron) or R-32 as the refrigerant. These refrigerants are commonly used in modern air conditioning systems due to their low environmental impact and high energy efficiency. R-410A is a hydrofluorocarbon (HFC) refrigerant, while R-32 is a hydrofluorocarbon (HFC) with a lower global warming potential than R-410A. Both refrigerants are non-toxic and non-flammable, making them suitable for residential air conditioning applications.