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

The HVAC UV light for coil treatment should be installed in the supply plenum just downstream of the evaporator coil. This location keeps the wet coil surfaces and drain pan in direct exposure, where microbial growth most often starts.

On horizontal or A‑coil cabinets, techs get better results when the bulb has clear line‑of‑sight to both the coil face and the pan rather than trying to light the entire plenum volume. In homes around Brighton, our technicians often mount the UV assembly on a serviceable panel to make future lamp changes quick and clean.

• Aim the lamp at the coil and condensate pan with unobstructed line‑of‑sight.
• Place it after the coil rather than before the filter or in the return.
• Provide gasketed mounting and enough clearance for safe bulb service.
• Tie power to an interlock or switch so the lamp shuts off when the door is opened.

Have a licensed HVAC pro install the unit and check for light leaks to protect eyes and nearby plastics.

Updated: 2026-10-02

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