It doesn't matter if you own your own home or rent — looking for and fixing leaks in air vents is an inexpensive fix that will save you cash come bill time. Up to 30% of your air conditioning can escape through vents that might have a gap or split. So save yourself some cash and check them out for yourself.
Although newer condos and apartments probably have sealed vent systems that live inside walls and floors, many older homes will have exposed duct work somewhere in the basement ceiling that can be easily accessed. Try lighting a stick of incense and hold it near the joints in your air conditioning ventilation system. If the smoke wavers, you know there is a small air leak.
Look for foil tape at your local hardware store and simply wrap it around the pipes or ductwork. It's as simple as that! It can save you big bucks come your next bill and let you enjoy all of your air conditioning without letting it escape!