A few days ago the A/C in our office started to "fail". One of the copper tubes was frozen, and the air going out of the vent wasn't too cold. We called another company who told us that it needed Freon, but actually we had a leak so replacing Freon wouldn't be enough... he said our best bet was to spend $4000 in a new unit. I wanted a second opinion and I called A Star. Philip came, inspected the A/C (both the Air Handler in the office and Condenser on the Roof) and said that everything was alright. No leak. No missing Freon. Apparently everything working OK and the "freeze" could have happened as a one time issue without consequence. He just charged the agreed upon diagnostic charge. A Star saved us from unnecessarily spending $4000 on a new unit. They surely were honest. And Philip was very knowledgeable. I would surely call them from now on.