UV Air Purifier vs. Media Filter: What's the Difference and Which Do You Need?

Strengths

• Removes the highest volume of contaminants by mass (dust, pollen, dander, spores)
• Effective for allergy and asthma triggers — addresses the most common IAQ complaints
• No UV bulb to replace; media lasts 6–12 months
• Works with any HVAC system — no electrical connection required
• Lowest cost IAQ upgrade with highest broad-spectrum impact ($400–$700 installed)

Trade-offs

• Does not kill biological contaminants — captures them but organisms may remain viable
• Higher MERV ratings (16+) can restrict airflow in standard residential systems
• Must be replaced on schedule — clogged media worsens system efficiency

Strengths

• Destroys mold at the evaporator coil — prevents coil fouling
• Inactivates airborne bacteria and degrades some viruses
• No particulate capture pressure drop — doesn't affect airflow
• Effective in the high-RH environment of the evaporator coil where mold thrives

Trade-offs

• Does not remove particulates — dust, pollen, and dander pass through unaffected
• Annual bulb replacement required (output degrades 15–20%/year)
• Coil-mounted UV treats only the coil surface, not circulating air broadly
• Supply-plenum UV treats circulating air but requires sufficient air contact time