We had a new AC system put in last summer. The contractor included a UV bulb between the cooling area and the supply fan. It's supposed to kill bacteria and other nasties in the air.
(The bulb is a Honeywell UV2400XLAM1 – Details here in case you're interested: https://customer.honeywell.com/resources/Techlit/TechLitDocuments/03-00000s/03-00011.pdf)
My question is "when should I replace the bulb?" Other than the obvious answer "when it stops working" I'm wondering if there's a point where (for whatever reason) it becomes less effective. Is it possible that the bulb could still be putting out visible light after it stops putting out UV, which I obviously cannot see?
These things are not cheap (they're around $70) so I'd rather not replace it sooner than I have to.
Thanks!
Best Answer
UV lights in both HVAC and water purification systems should be changed yearly.
This is also in the Honewell spec sheet for the UV2400:
Many systems have a timer and will start beeping and/or flashing a light after 1 year to remind you to replace them.
It's not that they will just stop working after that time, but that their output is reduced over time and they're built so they have an effective output for a year.
Should also be noted that the runtime is cumulative: if you only use this for 6 months of the year (and turn it off the other 6), you can go up to two years. The Honeywell documentation states 9000 hours (1 year = 8760 hours), which is typical of all water treatment UV systems (of which I have installed/serviced hundreds).