Are all HEPA filters the same

No, research suggests some air purifiers won’t effectively remove the amount of airborne pollutants as needed, yet they may be sold as having HEPA filters or having HEPA-like filters. It is important that the HEPA filter in your air purifier is a ‘true’ HEPA filter as defined by the Australian Standards, or other international Standards such as the US Dept. of Energy (DOE) and the European Standards (EN). To meet these Standards, they must have minimum filtration efficiency of 99.97% removal of tiny particles that have a size of 0.3 microns.

Both AUS5500 and AUS9500 Winix models have certified HEPA filters.