If you're living with leaky ductwork, you might as well just put a hole through your wallet. Improperly sealed ducts can lead to the loss of as much as 30 percent of the heated air that passes through, which means that you may be paying for a whole lot more heat than you're getting. Before you switch on the furnace this fall, take some time to identify any leaks in your ductwork. Call in a pro to test your system and make any necessary repairs. A little investment now can save you money and energy later.