Safety check on a gas system from 2016 using air filter 20*25*1 but capable of doing 20*25*4. Customer showed me the thermostat and how he uses it, normally keeps it at 74 sometimes his wife will turn it down to 72 but for the most part it’s set to 74. His electric bill is never over $200 and his only concern is that there is dust in the house. During my inspection I checked temperatures, checked electrical connections and components, checked for dirt buildup in the system, and tested overall performance of the system. I did find dirt buildup in the ductwork and some on the blower wheel, I showed the customer and informed him that this explains the dust in the house. For now he wishes to leave it alone but would like an estimate to get the ductwork cleaned. On the outside unit I found a burning and arcing contactor, customer stated that they do get power flickers or power surges. He requested an estimate to add surge protection to the system. As far the contactor he will keep an ey