The HVAC industry is transitioning to no ODP and very low-GWP refrigerants, best seen in HFOs and HFO Blends. HFO, R-1234yf, has the same operating conditions, thermal stability, capacity, and efficiency as its predecessor R-134a. While mildly flammable, it is typically used as a blend component with other refrigerants to lower GWP even further and can even be classified as A1.