I found Vader AC through the DWP AC optimization program. We were able to make an appointment very quickly and two very professional young men, Armando and Kevin, came on time. They explained everything they were going to do, were polite and pleasant and knowledgeable. It took about 90 minutes to do all the work. When they finished, they showed us what they had done, explained how to use the Nest thermostat that was installed and made sure we didn’t have any questions before they left. We recommend this company without reservation.