I was called to a home to fix a broken air conditioner. Upon arrival, I found that the unit was not cooling the house. I checked the thermostat and found that the temperature was set to 70 degrees, but the unit was not producing any cool air. I checked the air filter and found that it was dirty, so I cleaned it and the unit started cooling again. I also checked the refrigerant levels and found that they were low, so I added more refrigerant and the unit started cooling properly. The customer was very happy with the service and thanked me for my help.