You can tell a UV light in your HVAC system is working by visible signs (most have an indicator LED or viewing port that shows a blue/violet glow), bulb age (UV-C bulbs lose effectiveness after about 9,000 hours of use), and noting that musty odors, allergen issues, or coil mold haven’t returned. A technician can confirm with a UV meter during maintenance.
Quick checks
- Check the indicator LED on the ballast
- Look through the viewing port for a blue/violet glow
- Note the bulb installation date (replace yearly)
- Listen for the ballast hum
- Confirm during annual HVAC service
We test and replace UV bulbs during our annual Mainstream Maintenance Plan visits, and full indoor air quality service.
