Ask what problem the device addresses
A UV device is not a substitute for correcting a source of contamination. Ask the HVAC specialist to explain the intended target, placement and evidence for the particular device, rather than accepting a general “clean air” claim.
Check the system and instructions
Request the manufacturer’s installation and maintenance instructions. Ask the qualified installer how the device fits your equipment and how exposure, access and servicing are managed.
Compare the alternatives
EPA describes source control, ventilation and filtration as parts of indoor-air guidance. Read that guidance before comparing add-ons. This site does not prescribe a UV system or promise that it will prevent illness.