Spurred by lower operating costs, building owners this year are expected to nearly reach the halfway point in the replacement of comfort cooling chillers that use chlorofluorocarbons - the refrigerants that were banned from production in the United States at the end of 1995 because of concerns that CFCs erode the Earth's protective ozone layer.

According to a survey by the Air Conditioning and Refrigeration Institute (ARI), by the end of 2001 approximately 40,560 of the 80,000 CFC chillers in service in the early 1990s will still use CFCs.

New, non-CFC chillers reduce electricity costs, according to ARI, because they can be at least 40% more efficient than the CFC units installed two decades ago. During 2000, there were 3,235 CFC chiller replacements and 913 conversions to non-CFC refrigerants to bring the year-end total to 35,664 chillers (45%) that no longer use CFCs.