Recent Review: I came home late on a Friday evening, it was 85 degrees in the house, the thermostat was set at 72. Guardian had installed the our heat pump 8 years ago. I called around 6:00 PM, they arrived within 1/2 hour. The compressor had overheated and shut down. Guardian discovered it was a fault TXV value freezing up, stopping theflow of freon to cool the compress. After the unit was thawed out, the A/C was working again, but the TXV valve would need replaced. Lennox was closed so he couldn't check on the part until Monday. On Monday, he found the part approximately 45 miles away. He drove to pick up the value (at no charge) and replaced Monday afternoon. Great service, they will always be the first to be called.