When you want clean air in your home, a high-quality air filter generally does the trick for most homeowners. An air filter works by trapping particles in the air as they enter the filter, and are usually a few inches thick at most. Generally, these filters will need to be replaced between 2 to 6 months, depending on the quality of your air.
A UV light built for HVAC systems has a completely different design and purpose. It’s built to combat things like mold, bacteria, and viruses. UV lights are more expensive initially but can last longer than a regular filter before you need to replace a bulb. The best HVAC UV lights will stop germs from entering your home, but can also help keep your unit and ductwork clean. It can’t replace a traditional HVAC filter but works well alongside one to combat things an ordinary filter can’t touch.