With the official start of summer on Saturday, News 12 Brooklyn asked an expert about buying a new air conditioning unit, and how to keep the one you already have in good shape.

Howard Lupowitz, owner of Mike's Air Conditioning in Canarsie, says you should make sure the unit has enough Btu to cool all of the rooms in your home. He says a window unit is better than a portable unit because it is more energy efficient and is easier to repair.

Lupowitz says it's important to make sure your air conditioner is always clean and free from mold, which can make you sick. Dirty air conditioners can also pull more energy, leaving you with a higher bill.

Residents should always have their AC installed by a professional so that it is properly secured in the window.