The HealthPro Compact features the same advanced micro- and nano-particle filter technologies as the HealthPro and HealthPro Plus but in a smaller housing to make it more convenient in size for small apartments and offices only not upgradeable to HealthPro Plus to include V-5 Cell gas and odor filter. The HealthPro Compact effectively removes every type of particulate air pollutants with the same ultra high efficiency as the larger models including all common allergens microorganism and all types of dust. This makes the HealthPro Compact the ideal choice for allergy sufferers and other health-conscious individuals that need high-efficiency particle removal in a smaller size. (The HealthPro Compact cleans a home or apartment up to 900 square feet just like the larger HealthPro and HealthPro Plus but it is not upgradeable to to include V-5 Cell gas and odor filtration.). The HyperHEPA difference: Most air purifiers only filter particles larger than 0.3 microns in size but 90% of all ultra fine particles are smaller than 0.3 microns. This means that most air purifiers are only filtering 10% of the particles in your air. IQAirs patented HyperHEPA filters are the first filters tested and certified to filter down to 0.003 microns with a guaranteed minimum efficiency of over 99.5%. This allows your HealthPro to capture the ultra fine particles that other air purifiers miss.