A vacuum with a HEPA filter is a compromise.

• HEPA filters remove tiny, invisible particles from indoor air. Without them we would not have computer chips, modern pharmaceuticals, or space exploration.
  

• The HEPA filter can remove many contaminants that are recirculated by conventional vacuums, but not all. About half of all harmful contaminants get past HEPA filters; those between .3 and .2 microns in size.
  
  
• Also, to stop smaller particles, HEPA filters must constrict airflow, so that even with a new, clean filter the vacuum does not perform as well. HEPA filters clog quickly and reduce vacuum efficiency even further.
  
  
• HEPA filters are expensive; often over $100 just for one filter. They cannot be cleaned like many filters, but must be replaced several times a year.
• Finally, HEPA filter vacuums often do not filter well. Many leak dirty air around the HEPA filter. Besides, the HEPA filters fracture easily as the vacuum is dragged and bumped through the home, so the filter itself can often fail.
  
  
• HEPA filters are great for their intended purpose. But filter experts say HEPA filters were never designed for vacuum cleaners and should not be expected to perform properly in such machines.