Arrived at the customer's home to perform gas furnace maintenance. I completed the checklist, including checking the thermostat, gas pressure, and combustion analysis. I also cleaned the burners, inspected the heat exchanger, and tested the ignition system. I replaced the air filter and checked the electrical connections. I tested the thermostat and adjusted the temperature as needed. I also provided the customer with tips on how to maintain their furnace and answered any questions they had.