The answer is easy. Call Peoples Energy, give them the address, and they'll tell you exactly what it was last year. Usually they'll make you fill out a form and you have to submit it via fax. Do it, though. The anwer will give you some peace of mind. Multi-unit bldgs can have huge utility bills. If you're about to acquire a building, take Peoples Energy's answer and add 10%. Natural gas prices aren't coming down.