I am ready to purchase new Carrier high-efficiency furnace (96.6%) and air conditioning (15 SEER) units. Another contractor who carries the American Standard equipment, advised me to stay away from the Carrier A/C's because of the new Puron (R410) refrigerant. He pointed my to a website (www.icorinternational.com), that warns of the R410 having issues when the outside temperature exceeds 90 degrees. Is there any truth to this warning? Should I be concerned? Any advice would be greatly appreciated. Thanks.