Came out to perform preventative maintenance on furnace. Met with customer at front door and we began to discuss the maintenance, filter needing changed, thermostat operation and any issues. Customer stated that she had a filter waiting for me to change, and had questions about thermostat set temperatures and where/how to set them based on comfort level. Changed customer supplied filter. Inspected blower assembly, motor, electrical components, burners, flame sensor, hsi, safety switches, evaporator coil, heat exchanger and overall condition of system. Checked thermostat operation, wiring, amps, temperature rise and gas pressure. System is operating properly. Customer was dealing with some bad allergies and we discussed air purification and the benefits from it. After discussing it over with her, customer approved installation of an air scrubber in the system. This will help combat allergies and significantly reduce pathogens in air of the home. Installed the unit and went over warranti