These systems are generally considered non effective on cysts. Overall efficiency of these units is determined by the quality of the pre and post-filters employed. A high quality GAC post- filter must be used once again for chemical, chlorine, taste and odor reduction. Annual operational cost is based primarily on the values of the pre and post-filters as the energy requirements to operate the UV lamp is minimal, but there will be a recommended replacement interval and cost for the UV lamp. These systems to not require a storage medium, the water is processed as it is demanded.
Caution again is required while shopping as there are very few UV systems registered as purifiers.
In the process most impurities are left behind or driven off as gases. Also removed are minerals, which is a feature that does not appeal to all. 115 VAC is required for the heating element and units rated as purifiers are quite large. The major complaints about distillers however center on the time and energy they use. Without the use of pre filters cleaning becomes excessive and is another added expense.