"It is expensive, and it's a hassle, and we were pretty hot for a week," said Laura Rosales of Chino Optometry Center.
Rosales says she first noticed something was wrong when it grew uncomfortably warm inside the place where she works, the Chino Optometry Center.
"It was really stuffy inside, and normally it's really, really cool, but we didn't think that it was because they stole our air conditioning," she said.
Thieves have stolen A.C. units from a U.S. Ban, the Inland Empire Escrow and even churches like Living Word Assembly.
Authorities are unsure exactly why the A.C. units are being stolen.
"It's a possibility that it's being used for scrap, but again that's speculation, we're really not sure what they're doing with the units," said Michelle Van Der Linden from the city of Chino. "What we're really asking for is the community's help in reporting any suspicious activity they see."
Anyone with information is urged to call the Chino Police Department at (909) 628-1234.