Are You Struggling with Mold on Your HVAC Coils?

It’s an incredibly frustrating summer problem. You open up your HVAC system to check the evaporator coils, and despite having a germicidal UV lamp operating, you still observe mold or slime building up. This can result in adverse health consequencesopen_in_new, especially for those with allergies, asthma, or respiratory conditions. If your mold problem seems to get worse in the dead of summer when the AC is running constantly, the issue typically isn’t the UV lamp itself. It’s the temperature of the air hitting it.

Here is the blind spot that catches people off guard:

• The Cooling Effect: Standard UV lamps perform best in warm, stagnant air. The exact second your AC kicks on and blasts cold air (45°F to 55°F) across the lamp, its surface temperature plummets.
• The 50% Power Drop: That sudden cold airstream acts like a wind chill. It can cause a standard UV lamp to lose up to half of its germicidal poweropen_in_new right when the system is running the most and needs its protection.
• Optimal Temperature: According to ASHRAE, 90°F to 100°F is the ideal temperature for UV output. Lower temperatures hinder maximum UV output because there are not enough mercury atoms to generate full UV irradiationopen_in_new. Conversely, temperatures higher than 110°F cause UV output to drop and shorten the lifespan of the lamp.