Technician arrived to perform a promo tuneup on two trane furnaces. Technician adjusted gas pressure, checked amps, checked temperature differential, Checked static pressure, cleaned flame sensor, checked filters and insured proper operation. Customer was curious about a thermostat issue, but wants to buy his own for us to install. While checking filters, technician noticed dirty ductwork and made estimates for the customer on getting them cleaned and sanitized. Customer will call us in the future for thermostat installation and possible duct cleanings. Payment was collected for tuneup and both systems are heating properly at this time.