Shipments of gas-powered furnaces and central air conditioners increased in November 2010 while some water heater shipments declined, according to new figures from the Air-Conditioning, Heating and Refrigeration Institute.

Shipments of gas warm-air furnaces were up 11 percent from year-ago levels to 257,414 units. For the year, shipments were up 13 percent to 2,183,205 units, compared with 1,940,077 units shipped during the first 10 months of 2009.

Central air conditioners and air-source heat pumps were up slightly – 0.2 percent – to 4,826,685 units, up from a revised total of 4,814,764 shipped in November 2009. However, year-to-date shipments decreased 2 percent to 3,213,150 units, down from the revised 3,282,649 total.

Shipments of residential gas water heaters during November dropped 6 percent from year-ago figures. But shipments of commercial gas water heaters increased 5 percent and commercial electric heaters increased 16 percent.

The AHRI represents most of the major U.S.-based HVACR manufacturers.