Whole home water purification systems and point-of-use systems serve different purposes. Whole home filtration systems filter water at the entry point, ensuring purified water throughout the house. This feature is ideal for overall water quality and appliance protection. POU systems, on the other hand, provide targeted filtration at a specific point, like a kitchen tap, offering a higher level of purification for drinking water. While the filters in whole house systems are very fine (typically between 5 to 20 microns), they need to be able to handle the flow rate required by showers, taps, toilets and appliances, so the pores are typically too large to be able to filter out microscopic contaminants like cysts and some heavy metals. It’s usually more effective to use a smaller dedicated undersink point-of-use filter system to achieve this level of filtration.
Ultimately, the choice depends on your specific needs - whole home for comprehensive coverage or POU for focused purification.