Which type of refrigerant is commonly used in modern HVAC systems?

R-410A is commonly used in modern HVAC systems due to its favorable environmental properties and efficiency. It is a hydrofluorocarbon (HFC) refrigerant that does not deplete the ozone layer, which is a crucial factor considering the regulatory push towards environmentally friendly alternatives. Since the phase-out of R-22—a hydrochlorofluorocarbon (HCFC) that has a more significant negative impact on ozone depletion—R-410A has become the standard refrigerant for newer residential and commercial air conditioning systems.

Additionally, R-410A operates at higher pressures compared to R-22, which allows for better energy efficiency and performance in cooling applications. Its higher efficiency translates into lower energy consumption and operating costs, making it a popular choice among HVAC manufacturers and contractors.

While ammonia is used in certain industrial applications due to its efficient thermodynamic properties, it's toxic and requires careful handling and specific infrastructure that is not typical for residential or light commercial systems. Freon, often used as a generic term for a range of refrigerants, specifically refers to older types of HCFCs like R-12 and R-22, which are being phased out due to environmental regulations.