How to Choose the Right Air Purifier: A Guide to Cleaner Indoor Air
Most people spend 90% of their time indoors, yet indoor air can often be two to five times more polluted than outdoor air. If you want to know how to improve indoor air quality, this blog will help you determine the next steps for choosing the best air purifiers. To find the most effective indoor air purification system, it’s important to choose the best air purifiers for your specific living situation.
HEPA vs. EPA Filters: What’s the Difference?
For single room-level air purification, we recommend HEPA13 or EPA12 purifiers. These are generic names for filtration types that are manufactured by many different brands. HEPA filters are high efficiency particulate air (HEPA) filters, and HEPA13 filters are in the highest tier of HEPA filters in terms of efficacy. They’re able to capture the smallest particles, including those that are only 0.1 microns. Because of this, they’re able to capture a high percentage of total air pollutants, removing 99.97% of indoor air toxins, and are considered medical-grade filters. HEPA13 filters work by using 3 main mechanisms for filtration: diffusion, interception, and inertial impaction. In diffusion, small particles collide with gas molecules and are diverted from their airflow path, leading them into the path of the filter fibers. In interception, the particles following the airflow lines become captured by the filter fibers. Inertial impaction uses quick changes in airflow and the principles of inertia to trap larger particles, which are unable to change direction as quickly as the airflow and become trapped in the filter fibers.
EPA filters, or Efficiency Particle Air filters, are used in filtration systems and are able to remove a high percentage of air pollution in homes, usually around 99.95%. They use the same air filtration mechanisms as HEPA filters. Both filtration types are especially effective at capturing nanoparticles, like viruses, which are even smaller than microparticles. The physics used in diffusion, interception, and inertial impaction are what make HEPA and EPA filters so effective in capturing such small particles, even though the particles themselves are even smaller than the gaps between the filter fibers. The one key difference between HEPA filters and EPA filters is the effectiveness - EPA filters tend to capture around 99.95% of particles, while HEPA filters capture around 99.97% of particles. So, HEPA filters are more effective than EPA filters, but EPA filters do tend to be more cost effective due to this discrepancy.
HVAC Filtration Systems for Whole-Home Air Quality
If you’re in the market for building-level HVAC integration, we recommend electrostatic in-duct filtration. This type of filtration system cleans air filtering through your house’s heating and cooling system by using static electricity to capture particles. Rather than passively collecting particles that flow through the filter, electrostatic in-duct filtration attracts particles and is able to capture a higher percentage of air pollution in homes. These filters tend to be better at capturing larger particle sizes, like pet dander and dust, and effectively filter out 99% of particles down to 0.3 microns. However, they tend to struggle with particle sizes smaller than 0.3 microns, like the bacteria and viruses that HEPA and EPA filters are so effective at capturing.
Another good option for building-level HVAC integration is bipolar ionization if the unit is able to convert resultant ozone back into oxygen. Bipolar ionization devices are meant to be paired alongside existing HVAC systems. These devices work by splitting molecules into positively and negatively charged ions. The ions then cluster around particles floating in the air, and make them big enough to then be captured by the HVAC system. The ions not only make nanoparticles bigger, they also physically alter certain viruses and pathogens. They can alter the protein coating of viruses and other pathogens, which is essential to the infection process, essentially deactivating them and removing their ability to make us sick. Bipolar ionization systems would be great to use in buildings that already have HVAC systems with electrostatic in-duct filters. With this combination, you’d be able to effectively capture a wide range of particle sizes without over-stressing your HVAC system.
Choosing the Best Air Purifiers for Your Space
Between HEPA13 or EPA12 filters, electrostatic in-duct filtration, or bipolar ionization, hopefully this blog will help you understand the pros and cons of each recommended indoor air quality system and how to improve indoor air. Use this blog and the table below as guides to determine your individual air filtration needs and choose the best air purifiers.
For more information on indoor air quality, check out our blog on the essentials of indoor air quality, or our blog on the impact of indoor plants on air quality. For more information and recommendations for healthy home improvements and to join a like-minded community, subscribe to our newsletter for blog and podcast updates.
