One way to tell if your air conditioner is leaking Freon is through smell. If it emits a chemical smell, then there might be a leak, and you'll need to get your AC repaired as soon as possible. You can also check for leaks visually by looking for discoloration or puddles of liquid on the floor near the AC unit. Finally, you can test for leaks by using a special tool that registers escaping Freon. If you have any suspicions that your AC is leaking, contact an HVAC specialist for help.