With the temperatures on the rise, Brooklyn hardware store owners say air conditioners are selling like hot cakes, but to save money, they say customers must know what they need.

John Scalon, an air conditioning specialist at the Pelham Bay Home Center, says that before buying an air conditioning unit, people should know the size of the room, the size of the window and the required voltage.

Experts also say that buying the cheapest air conditioner model will cost more in the long run because they are less energy-efficient.

?It'll be spinning around like a race track, costing you more money in a couple of weeks for anything you may have saved to begin with,? says Bernard Harrigon, of Mazzone Hardware Center.

Customers are advised to look for models with the Energy Start logo, which means the appliance will use up to a quarter less energy that a conventional model.

Besides pricey air conditioners, fans are also an option, especially on cooler days, because they use far less energy.

Con Edison says one strategy to cut the electric bill by 40 percent is to alternate between the air conditioner and the fan throughout the day. Con Edison also recommends not to set the air conditioner below 78 degrees.