ARLINGTON, Va. - The Air-Conditioning and Refrigeration Institute has dropped its challenge of a Department of Energy regulation requiring a 30 percent increase in the seasonal energy-efficiency ratio for residential air conditioners and heat pumps.

A lawsuit had been pending in federal court since 2001.

"Due to the likelihood of a long and uncertain legal process, ARI will no longer pursue litigation ... so that manufacturers can prepare for a new, 13 SEER national minimum-efficiency standard," institute President William G. Sutton said.

"Manufacturers face significant challenges in meeting the deadline for the 13 SEER standard, which is less than two years away. The industry needs to know with certainty what the standard will be in order to meet the needs of the marketplace."

The current 10 SEER standard, which went into effect in 1992, will continue to be in place until Jan. 23, 2006, when new equipment must meet the 13 SEER standard.