Came to residence for prepaid MSC tune-up on a '10 ac system. Equipment functional upon arrival. Upon inspection of the outdoor condenser, we found all components and measurements are within manufacturer specifications. Moving inside, we found the 20x25x1 filter was dirty and replaced it. The thermostat was having some issues as it is pretty old and the cool button on the side is broken. The homeowner is considering upgrading. We also found the furnace is one of the ones under recall/warranty for potentially bad secondary heat exchangers. We inspected the secondary heat exchangers and found them in good condition, but they will need to be monitored for a few years. We also found the humidifier pad is degraded and in need of replacement, and the humidifier drain line is very clogged and needs to be cleared/replaced. Homeowner said she will likely schedule for a return visit for that in mid April. The blower wheel is also dirty and should be cleaned soon. The homeowner will likely wait