Came out to call for a customers concern about the AC not cooling properly. Customer stated that the thermostat didn’t seem like it was working. I checked system over and found the AC operating properly and refrigerant pressures were good. Advised customer about the type of thermostat and how it can not be as accurate when it’s older. Customer wanted the thermostat replaced with something identical and not digital. I picked up another kind of analog thermostat and replaced it the existing one. Filled gap behind thermostat with tape, and secured it to the wall. Tested new thermostat to make sure it worked properly. Discussed with customer about where to set thermostat during the day. Customers get cold easily so I suggested customer keep it at around 74-76 and see how that works out for them.