INTRODUCTION It is well documented (Oranski 2012) that there are many benefits to continuously removing dirt from HVAC water systems. However@ the debate on how to apply@ how much to apply@ and what type of filtration continues. This paper will compare on a broad scale the advantages and limitations of barrier filtration vs. non-barrier filtration. Also@ the comparison brings into discussion the types of solids typically present in HVAC water systems and filtration types best suited to remove them. The results of this comparison will be applied to the specific application types on HVAC water systems so the reader can quickly determine which technology will help achieve energy and water savings within a framework of physical space and lifecycle costs.