Healthy Buildings

Providing Insight Through Integrated Understanding of Energy Use
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Air Filters: MERV 1-16

The simplest and probably most cost-effective recommendation for your workplace is to upgrade your filters to a minimum of MERV-13+ air filters (ASHRAE Standard 52.2-2017)​. MERV Filters: Minimum Efficiency Reporting Value has a scale goes from 1 to 16. 16 is the most efficient in terms of capturing particulate matter.

HEPA filters

All HEPA air filters must meet a minimum efficiency of 99.97% at 0.3 microns, which means that if 10,000 particles of dust, pollen, mold, bacteria and or any airborne particles with a size of 0.3 micron or greater enter, then 9,997 particles would be captured in the filter (U.S. Dept. of Energy). HEPA filters also can reduce the air flow and are more expensive than the MERV filters, so again consult before installing.

Air Purification Systems

More comprehensive and costly recommendations are one of the air purifications systems in the marketplace. Below we will explore some of the subtleties surrounding the purification systems. Keep in mind, in all our consultations, we endorse what we believe is best for our clients based on data and results rather than pushing a specific brand for the sake of loyalty.

UV-C Light Systems

  • UV energy inactivates viral, bacterial, and fungal organisms so they are unable to replicate and potentially cause disease​
  • Types of disinfection systems using UV-C:​
  • In-duct air disinfection​
  • Upper-air disinfection​
  • In-duct surface disinfection​
  • Portable room decontamination
GPS Bipolar Ionization

  • High voltage electrodes create ions in the air that react with airborne contaminants, including viruses.​
  • Ions combine on surface of a​ pathogen and robs it of the hydrogen​ necessary for them to survive.

Bi-polar ionization is the of the most effective technologies for air decontamination. Since the ions generated with the system will be passed along within the airstream, the effectiveness to reduce certain pathogens can be very effective.

Installing both UV and Ionization systems in a single system has no significant downside other than the additional costs. Both can work independently and they will not counter the effectiveness of the other. Both technologies have similar effect on viral, bacteria and fungus organisms.

UV-C systems are most effective for surface decontamination. A short period of time of exposure to the UV-C light to improve effectiveness is needed, so constant exposure of a cooling coil or drain pan in an AHU system will be the best benefit. The engineered solution for UV-C includes the analysis of coil dimensions, the thickness of a coil so that UV-C light can penetrate the depth of the coil and proper UV irradiance levels to all surfaces are obtained.

Overall, both systems have varying effectiveness depending on the contaminant. Both systems have been tested in national laboratories with published results. Neither solution have 100% guaranteed results, but both have success in reducing various particulates, pathogens and other VOCs.

Health Performance Indicators


HPIs can be divided into four quadrants according to the timing of
indicators and what they measure

The top half of the grid above highlights examples of HPIs you should track among your workforce, while everything on the bottom half points to HPIs you should track in your building. There are a handful of tools you can use to get started, like real-time sensors to monitor CO2 as a proxy for ventilation rates, and particle sensors to let you know if a nearby pollution source is impacting your building. More granular testing will be required for other measurements, such as air and water sampling techniques.