With 45% of the total energy use in the UK attributed to space heating and cooling. System efficiency and performance has become an important and essential topic towards building decarbonization. In this research paper, the system volume flow was observed and studied to assess how it impacts the performance of a magnetic side stream filter unit in restoring system efficiency and reducing energy consumption of the system. To mimic a hydronic closed looped heating system, tests were carried out using a purpose-built experimental stainless steel pipe rig allowing for system parameters to be controlled and monitored. To replicate a dirty system, magnetite powder was dosed into the system to emulate system corrosion. This research also introduces the use of infrared (IR) thermography as a means of system performance monitoring and diagnostics and spotting system failure and blockages due to corrosion. The results found that under low velocities the filter was not able to collate any debris and no energy savings were attained. At higher system velocities the filter was more effective at restoring system efficiency to clean conditions, with some cases the system efficiency was restored by up to 96%. However, the results also showed that if the filter is not maintained and cleared properly overtime, it can lead to excessive energy use. IR thermography was accurately able to show that overtime the filter will reach a saturation point and will lead to clogs and blockages around the system. The IR thermography was also able to accurately pinpoint the area of blockages in the system, thus allowing for timely intervention and maintenance.