I preformed dryer vent cleaning, before I started I noticed the vent pipe for the dryer vent was detached from the roof where it exits and sending lint into the attic. Client stated they would fix the issue themselves. Preformed maintenance on a 2016 single gas. I tested all electrical components and safeties. All tested within manufacturer specifications. I did notice that the ducts had a sufficient amount of build up in them.client did not have filters at the time of inspection 20x25x4. I provided estimates to have the ducts cleaned. Unit was cooling upon departure.