Where should HVAC UV light be installed near the evaporator coil?

HVAC UV light should be mounted in the supply plenum just downstream of the evaporator coil, aimed at the coil and drain pan for steady, direct line-of-sight exposure. Most microbial growth starts on the cold, damp coil, so shining UVC there helps keep the surface clean. Technicians in the Boise area often pair this placement with whole-home filtration when better indoor air quality is the goal, and Diamond installs whole-home UV systems that can be combined with filtration as noted on our site.

Look for these placement details during installation:

• Aim at the wet side of the coil and pan; avoid shadows from sheet metal or wiring.
• Respect the lamp’s clearance rules and keep plastics and wire insulation out of the beam.
• Leave clear access for lamp changes and prevent UV spill into the filter area.
• Seal the access panel to stop light leaks.

Always shut off HVAC power and never look at an operating UVC lamp without proper shielding.

Updated: 2026-09-30

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