The IQAir Replacement HyperHepa Filter for the HealthPro Series is a remarkable filter capable of filtering even the smallest of particles. The IQAir HyperHepa Filter should be changed every two to five years with normal use. IQAir’s HyperHEPA filtration is tested and certified to filter down to 0.003 (0.000000118 of an inch) microns in size with a guaranteed minimum efficiency of over 99.5%. This is 100 times smaller than what can be achieved by ordinary HEPA technology. (This is literally smaller than the smallest virus or bacteria.) There are no particles smaller than 0.003 microns, as anything smaller becomes a gas. This means that IQAir’s patented HyperHEPA can remove all particle sizes, down to the very smallest particles that can be measured, and it does so at an efficiency rating that has never before been achieved in a home air cleaner. IQAir’s HyperHEPA filter has received the official H12/H13 certification. This gives you the cleanest, freshest air that has ever been possible in your home.