So everyone knows that you are supposed to change your UV bulb at least once a year right? Well thats great that we all know what we are supposed to do, however I want to know the whys.

My UV light is one year old and I replaced that bulb, however the old bulb is still lit and appears to be working. So my question is: Why should we spend 50-100 or whatever it may cost to replace a working UV bulb??? Regardless of "what is recommended"

Below is one article that I found talking about UV life span, from what it says most manufactures define it as when the bulb drops down to 70% of its normal output. If you are like me I bought a larger size UV then what I actually needed so 70% efficiency is actually still very good .....

So why replace a UV bulb when its still working?????????

Preston

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http://www.hvacuv.com/pdf/Introducti...f-UV-Light.pdf

Many factors are associated to the overall lamp life of UVGI Lamps. UV lamp manufacturers have developed
lamp life ratings for certain types of UV lamps based on set operating currents and ambient conditions. The
lamp life rating has been established at a point when the lamps intensity drops to 70% of the lamps original
output. This standard was originally developed for the use of UV lamps for water disinfection, as it has been
found that if intensities drop below the 70% level, then optimum disinfection may not be achieved. This
standard has been adopted for many other UV application, however, to date there has not been a standard
developed specifically for IAQ applications. Some typical lamp life spans are outlined in the table below: