Performed single system cooling maintenance. I checked amps, capacitor filter, electrical, cleanliness, drains, temperature difference, refrigerant temperature, washed the outdoor unit with water. The system is cooling within manufacture specifications. The customer and I spoke about the son’s room not cooling very well. I inspected the ducts involving the son’s room. There is a duct feeding what appears to be 3 ducts. This will never work properly. I provided pricing to run a direct duct to the system to feed that room. Per the air sample, the home has higher than normal particulate value. I spoke with the customer about adding an air scrubber to produce negative ions in the home. This will allow the particulates to clump better allowing the filter to catch it. Some particles are too small for the filter to filtrate it. I spoke with the customer about the importance of back-up water safety switches and drain treatment to help keep the home safe from potential water damage. I info