The frequency of changing a UV lamp for effective indoor air quality improvement depends on how you are using the system. Typically, a UV lamp being used primarily to disinfect the air circulating through a home or small office should be replaced every 9000 hours or approximately every 12 months. For people with respiratory conditions or other acute sensitivities, we strongly recommend keeping to an annual lamp replacement schedule for the best control of airborne microorganisms and allergens.
Replacing a lamp before it literally “burns out” may seem wasteful but not when it comes to UV light. After the first year, all UV lamps by their fundamental design will have lost nearly half of their germicidal effectiveness. That’s why, for air disinfection – where the target organisms are moving with the airstream and have a short exposure time – it is critically important to keep to your one-year replacement schedule.
However, if your UV lamp is being used more for keeping the HVAC components clean of mold and other bio-growth, then the lamp can be replaced every two years – its maximum lifespan. This saves money (and the environment). UV lamps used for component irradiation have a stationary target: the mold or microbes that try to colonize on them. Therefore UV exposure time is much longer so less intensity is needed to prevent growth.
A UV lamp should not be kept running after 3 years. The UV system should just be turned off until the lamp is replaced, because it effectiveness is spent and it will simply waste energy. The excessive energy consumed by an aging lamp can cause the power supply to overheat, potentially causing a complete system failure.
Always remember to heed all warnings and never look at an operating UV lamp.
If you have questions or it’s time to change your lamp, contact your HVAC contractor. They are your primary source for expert consultation because they have direct experience with your particular HVAC system.
