The Aprilaire Model 5000 is an industry leader amongst air filtration devices, able to reliably block particles as small as 1.0 to 0.3 microns in size, smaller than any particles blocked by the Merv 13 or Merv 11. Just like the Merv 13, the Model 5000 also blocks 98% of particles larger than 1 micron in size, keeping them from contaminating your air stream. Unlike many other types of air filtration devices, Aprilaire’s Model 5000 operates in complete silence.