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

HVAC UV light should be installed on the air-leaving (downstream) side of the evaporator coil with an unobstructed line of sight to the coil surface and drain pan. This placement targets the most common issue—microbial growth on the cold, damp coil that can create odors and reduce efficiency. For durability and access, mount the fixture so the lamp runs parallel to the coil face, with enough clearance to replace the bulb without disturbing refrigerant lines. In our day-to-day work around the Lexington area, placing the lamp just past the coil keeps the coil drier and cleaner between maintenance visits.

Use these quick placement cues:

• Downstream of the coil, not upstream, to bathe the wet side and pan.
• Direct line of sight to coil fins and pan; avoid shading from brackets or wiring.
• Lamp parallel to coil face; secure to the plenum, not to insulation.
• Leave a service panel path for bulb changes and include a safety interlock if provided.

Always shut off power and avoid UV exposure, or have a licensed HVAC technician perform the installation.

Updated: 2026-10-26

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