Product review (2 stars): Save the money for something else.
Update: moved to three stars.
Does seem to help out in coolers & dehumidifier-things that are 100% emptied. Utterly useless in my Sears, Holmes, and Laslo humidifiers. Laslo has a circulation over the filter [with viewer]. This product increased build up on filter, viewer.

Definitely DOES NOT EXTEND FILTER LIFE, NOR DOES IT CLAIM TO.

Doesn't seem to do much. A routine 409- about the same amount of disinfectant still necessary- tried the "freshener" kind too. It's 2 stars tops.