Replacing the bulb every six to nine months will maintain the mold spore "kill rate" at quite nearly 100%.

In cities such as AUstin, mold is a year round problem. As a result, we recommend that you leave the light on 24 hours a day, year round, and wipe the bulb off every 30 days. With such usage, the UV light bulb will be extremely effective for about nine months. After that, although it will still put out the same visible light, the wavelength for its "germicidal" potency will be reduced.

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