I was called to perform a routine heating maintenance on a residential property. The client had noticed that their heating system was not working as efficiently as it should be. I arrived at the property and performed a thorough inspection of the heating system. I checked the thermostat, the furnace, the air filters, and the ducts. I also checked the gas line and the electrical connections. I found that the furnace was not producing enough heat and that the air filters were dirty. I cleaned the air filters and replaced the furn