R-410A is a chlorine-free refrigerant that meets the U.S. EPA's newest, most stringent environmental guidelines. R-410A was developed as an alternative to R-22 (Freon), which will be phased out over the coming years in response to international environmental concerns.
R-410A contains no chlorine, so it’s not damaging to the atmosphere’s ozone layer. As an added benefit, Lennox laboratory analysis and independent testing have shown that R-410A allows higher heat transfer than R-22, resulting in more efficient operation. So choosing an air conditioner with R-410A not only makes sense environmentally—it also makes sense from an economic standpoint.*
Learn more about the difference between R-22 and R-410A refrigerants
*http://www.itpaystolivesmart.com/residential/cs_whyr410a.asp