Another concern was making sure that the system delivered the efficiency its customers were paying for.
In one case, the company did an a/c retrofit for a house in Lake Worth, a suburb of Fort Worth. "This house is 103 years old," Mulholland said, "built out of stone that came from the riverbed. It has been added onto three or four times." The original part of the house, built in 1903, consisted of one room, he said. A 1910 remodel added one more room. A 1930 addition created what is now the rest of the house. The old furnace was installed in a closet.