Performed Fau maint on 2016 Lennox System. Cycled system for heat. Checked electrical and system components. Temperature split between supply and return is in range. Blower wheel and evaporator coil is within range. Replaced filter with filter provided by homeowner. Brushed off any dust that was inside of the filter cabinet. Homeowner stated that she noticed more dust than usual. Homeowner previously was Using a humidifier inside the bedroom and living room without filtration, which in return caused the return ducts to her fairly dirty . Recommended adding a whole home air purification system to help with the dust inside the home that the humidifier has caused. Homeowner said she is going to try a new humidifier that comes with its own filter. Cycled system, system is fully operational upon departure.