• Next-Gen Corsi-Rosenthal Box

    Quiet air purifiers that actually clean your air

    High airflow, low noise, and no proprietary filters. Simple systems designed to run continuously, so you don’t have to think about it.

    High airflow, low noise, and no proprietary filters. Simple systems designed to run continuously, so you don’t have to think about it.

    Find Your Kit

Simple by design

CleanAirKits are designed to be straightforward, effective, and easy to set up.

Most customers choose the DIY kit option, which arrives flat-packed and assembles in minutes with no tools required.

Prefer something ready to go? Pre-assembled options are available for a more plug-and-play experience.

Always On Safety

Since a Clean Air Kit is not loud and power hungry like most HEPA purifiers, it can always be running. And if it's always running, it's always adding a layer of protection for you and your family from smoke, molds, pollen & airborne pathogens like Colds, Flu, Measles, Strep, RSV, and Covid.

This corresponds to the pandemic HVAC best practice of continuously running furnace fan circulation with MERV13 or MERV14 filtration.

  • Scientifically Optimized

    We tested dozens of fan & filter combos to create unprecedented efficiency in: Price, Energy, Noise.
    Want a quick sizing rule for meeting ASHRAE 241 Control of Infectious Aerosols in homes & classrooms?
    One PC fan per room occupant

  • 3M Virus + Allergen Filters

    In EPA tests, a MERV13 CR Box drew down 97% of bio-aerosols in 30 minutes and 99.4% in 60 for a 3000 cb ft chamber. 3M Filtrete have the highest airflow amongst MERV13 brands, enabling a compact design with 1" thick filters. Replace with Filtrete 1900 or 2200 @ 6-12 months

  • Silent Pressure Fans

    Not all fans can pull thru MERV13. We identified the best value "High Static Pressure" fans from popular gaming PC vendors like CoolerMaster

  • Easy Slip-In Filter Changes

    Foam weatherseal and pre-tensioner bungees keep filters snug. Guards slide off & filters slide out and back in for replacement every 6-12 months.

Contagion Risk decays exponentially with faster air cleaning

March 2022: Study of 10,441 Italian Classrooms with varying mechanical ventilation up to 6 ACH.

  • Large Capacity

    Choose clean air delivery rates up to 500 cfm -- comparable to the largest HEPA purifiers and C-R cubes. Lowers viral concentrations substantially within classrooms and dining rooms.

  • Quiet on Full

    Clean Air Kits produce 5-10x less noise than HEPA purifiers at max capacity.

  • One Speed Design

    Speed controls defeat the efficacy of most HEPAs -- people turn them down to quiet where air cleaning slows. We have just one speed: silent full blast!

  • Unprecedented Energy Efficiency

    Decades of competition has driven amazing silence + efficiency in PC fans. Our fan banks use 6-16W -- comparable to a LED bulb!

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Trusted by air quality professionals

  • The PC Fan #CorsiRosenthalBox


    “I’m now a convert to PC fan CR boxes. The airflow and noise levels are incredibly impressive, especially for everyday spaces. These are unbelievably quiet.”

    Joey Fox
    HVAC Engineer,
    Indoor Air Quality Chair,
    Ontario Society of Professional Engineers

  • “I think PC fans are the future of portable air cleaners. Noise is the biggest challenge, and these designs solve that problem incredibly well. The airflow and sound levels are genuinely impressive.”

    Joey Fox
    HVAC Engineer,
    Indoor Air Quality Chair,
    Ontario Society of Professional Engineers

  • “Standalone HEPAs or Corsi-Rosenthal boxes are an effective way to reduce airborne virus exposure. Filtering viruses out of the air lowers the chance of inhalation — simple logic.”

    Kim Prather, PhD
    Distinguished Professor, UCSD
    Director NSF Center for Aerosol Impacts
    on Chemistry of the Environment

  • “3M testing found the Corsi-Rosenthal Box performs exceptionally well at capturing airborne particles, including viruses.”

    Fortune: A DIY air purifier that costs
    under $100 to make is taking Americas
    classrooms by storm

  • “A C-R box combines strong airflow with effective filtration to clean more air in shared spaces. What it may lack in filter efficiency compared to some HEPA systems, it makes up for in total clean air delivery.”

    Fortune: A DIY air purifier that costs
    under $100 to make is taking Americas
    classrooms by storm

  • “Cleaner indoor air has major health benefits beyond COVID-19, including reducing airborne pathogens, wildfire smoke, and other pollutants we encounter every day.”

    Kim Prather, PhD
    Distinguished Professor, UCSD
    Director NSF Center for Aerosol Impacts
    on Chemistry of the Environment

  • To lower inhalation dose of virus-laden respiratory aerosol particles (a major key to suppressing the mortaility and mobidity associated with COVID-19) the three Rs must be advanced from where they are now. Remove, Reduce, Remediate.

    Richard Corsi, PhD PE (Texas)
    Dean of Engineering, UC Davis

  • Appropriate combos of Remove, Reduce, & Remediate are what many of us called layered risk reduction (or layered inhalation dose reduction) back in Spring 2020. Not rocket science. For those who still care about reducing the spread of COVID-19, it all still applies, folks.

    Richard Corsi, PhD PE (Texas)
    Dean of Engineering, UC Davis

  • "I am thrilled to be part of something that is so accessible to people around the world, helping to protect children in school and families in their homes, all the while inspiring children about the power of STEM."

    Richard Corsi, PhD PE (Texas)
    Dean of Engineering, UC Davis