AHRI announced that combined U.S. factory shipments of central air conditioners and air-source heat pumps for May totaled 631,716, down 14 percent compared with the same month a year ago.

The Air-Conditioning, Heating and Refrigeration Institute also said that for the year to date, combined shipments totaled 2.4 million, a 9 percent drop compared with the same period last year.

Heat pump shipments for May totaled 183,804, down 8 percent from the same month a year ago. For the year so far, heat pump shipments totaled 768,422, a 5 percent drop compared with the same period last year.

U.S. factory shipments of gas warm-air furnaces in May totaled 156,208, a 23 percent drop compared with the same month a year ago. Oil warm-air furnaces for the same month totaled 2,860, a 20 percent drop compared with May 2007 totals. For the year to date, gas furnace shipments totaled 820,922, an 18 percent drop compared with the same period last year. Oil furnace shipments for the year to date totaled 19,308, a 26 percent drop compared with the same period last year.

A total of 17,303 vent-free room heaters were shipped in May 2008, an 81 percent increase compared with the same month last year. For the year-to-date, 33,957 units have been shipped, a 28 percent increase compared with the same period last year.

Residential electric water heater shipments for May totaled 354,395, a 2 percent drop from the same month a year ago. Residential gas water heater shipments totaled 335,156, a 9 percent drop compared with shipments for the same month last year. For the year-to-date, 3.5 million residential gas and electric storage water heaters have been shipped, an 8 percent drop compared with the same period a year ago.

Commercial gas water heater shipments for May totaled 7,317, dropping 5 percent compared with the same month last year, while commercial electric water heater shipments totaled 5,786, jumping 6 percent compared with the same month a year ago.

Electric water heater shipments are 7 percent ahead of total shipments of this product during the same period last year. Commercial gas water heater shipments for the year so far are up 0.4 percent, compared with the same period a year ago.

May gas logs and insert product shipments totaled 9,789, a 39 percent drop compared with the same month last year. Gas fireplace shipments for May totaled 1,948, a 37 percent drop compared to the same month last year.