Upon arrival customer stated they noticed white smoke coming from only one vent in house this morning from downstairs unit, inspected vent found no signs or smell of smoke , vents are dusty, with no return or supply grills , cycled tstst to heat mode, unit started up, heat coming from all vents and no signs of smoke, went into attic, inspected filters, recommend replacing, customer will pick up filters and replace themselves, pulled out apco and inspected supply plenum, no issues, made sure duct they seen smoke from was attached with no issues as well, explained to customer not sure why the one vent would have been smoking and not all vents downstairs, customer will keep eye on vent and send video if it does it again, customer wanted upstairs supplied tstat installed, customer is aware no warranty on tstst, installed new nest tstat configured and set up on customer phone, cycled heat and ac mode to make sure both modes are working, recommend duct cleaning but customer wants to wait du