New York Times: ENVIRONMENTAL PROTECTION AGENCY rules that take effect on Jan. 1, 2010, are part of a gradual shift to a new class of refrigerants for window units, central air-conditioning systems, heat pumps and the chillers used to cool large residential and office buildings. Some heating and cooling companies are suggesting replacing old equipment now to accommodate the new refrigerants, and some utilities are offering rebates. But there is nothing in the regulations to compel getting rid of an …