HEPA stands for High Efficiency Particulate Air. HEPA filters remove at least 99.97% of particles 0.3 microns in diameter. The question is, does having a HEPA filter on a vacuum cleaner make the vacuum cleaner HEPA certified, and the answer is NO. While a filter may pass as HEPA, the vacuum cleaner itself can leak air that is not passed through the filter. This leakage is due the quality of materials used to manufacture the body, body component seals and the quality of the assembly process. Let’s look at each one.

1. Quality of materials. Vacuum cleaner motors generate heat which will warp the plastic body and allow air to leak out before it passes through the filter. Miele has solved this problem by using ABS 28 (football helmet) plastic that holds up to the heat generated by the motor.

2. Body Component seals. Due to the pressure created by forcing air through an exhaust filter, a vacuum cleaner’s body components should have three separate seals; one motor seal and two housing seals. Some manufactures will use a foam type of seal that is glued on. The best seals are molded rubber fitted along body seams.

3. Quality of assembly process. Vacuum cleaner body parts can be ‘snapped together’ or bonded with screws.

Manufactures have the option of obtaining a Vacuum Cleaner HEPA certification for any or all of their models. This certifies the whole vacuum as HEPA not just the filter. The filtration standard used is EN-1822, the world’s most stringent standard. To date, the Miele Company is the only manufacture to have their vacuums rated and approved as HEPA.

Another aspect of HEPA filtration for vacuum cleaners is the pre HEPA filtration supplied by the disposable bag and motor filter. For the HEPA filter to work at its best, air must flow through the filter. This ‘airflow’ can be restricted by poor quality disposable bags and motor filters. Machines without bags or ‘bagless’ vacuums are the least efficient at maintaining air flow and have filters that clog easily. Manufacture’s that claim their bagless vacuums ‘never loose suction’ do not make the claim their vacuums don’t loose airflow. Vacuum cleaners with high quality cloth disposable bags maintain the best airflow, even as the bag fills up.