The Air Reactors work a bit differently than a typical filter based air purification system which trap contaminants in a filter. The Air Reactors produce super OH Radicals which are propelled out of the machine and into the indoor environment. In early testing it was found that one Model 101 would address up to approximately 12,000 cubic feet of air (1500 sq. ft. with 8 ft ceilings) with adequate concentration of the OH radicals to adequately reduce existing mold and mycotoxins (no active leaks). In the case of an active leak or active mold growth it is recommended that you use two Model 101 for the same 12,000 cu. ft. of air volume. This doubles the concentration of the OH Radicals to ensure they can destroy the mold spores and mycotoxins that are expelled from the mold colony at a rate faster than mold can reproduce or create mycotoxins. Additionally, it has been found that most homes do not have adequate air mixing between levels and therefore it is recommended to have at least one Model 101 on each level (required number of units is always based on the air volume on that level).