How can Improving Indoor Air Quality (IAQ) Help Reduce the Spread of COVID-19?

Until we find a vaccine or an effective antiviral treatment, COVID-19 (coronavirus) will continue to be a major health and safety hazard, particularly in enclosed spaces where its spread is more likely to occur. Many Americans work in large office buildings and nearly 60 million Americans live in apartment buildings, which puts them at an elevated risk of being exposed to infectious aerosols like coronavirus.

To help facilities install the appropriate and effective technologies in the fight against COVID-19’s spread, EN-POWER’s engineers and lighting experts can help you implement an indoor air quality program through our CDC strategy, which encompasses UV-C lighting, air filtration, and mechanical ventilation improvements. 

The CDC strategy is the infectious aerosol reduction method approved by the American Society of Heating, Refrigeration, and Air-Conditioning Engineers’ (ASHRAE) to help reduce the spread of COVID-19 in buildings, and encompasses three key principles:

Clean infected surfaces and spaces.

You should:

  • Clean and disinfect high-use surfaces with the use of EPA-approved products. The Center for Disease Control and Prevention offers this very helpful site on best cleaning and disinfection practices.
  • Ultraviolet germicidal (UVG) lighting is a widely-recognized cleaning method that utilizes UV-C light to disinfect viruses, mold, and bacteria to sanitize air. UV-C products have been used in air handling systems, elevators, and operating rooms to disinfect. However, not every product is appropriate for every application. Be sure to discuss your specific needs with EN-POWER so we can analyze what would be effective for your building.

Dilute the air in buildings to reduce the concentration of potential COVID aerosols.

You should:

  • Increase the supply of fresh air, increase mechanical exhaust ventilation, and minimize the recirculation of air within a space. All three are key to reducing transmission of viral droplets in buildings
  • Replace filters on a consistent schedule. However, keep in mind this alone will not prevent the spread of airborne viruses. Regularly maintaining the equipment to check all components are working is of paramount importance to ensure the delivery of fresh air into spaces.
  • Review the performance of your mechanical ventilation system to ensure proper and optimal operation, including exhaust fans, air-handlers, and their respective control systems and components. Our commissioning (Cx), controls, and mechanical engineers can advise how to integrate a dilution strategy and ensure your mechanical systems are performing properly so you have the best indoor air quality.

Contain airborne viruses.

Simply explained, if you can smell a neighbor’s cooking or smoking, a virus can be transmitted from one apartment to another. Containment can mean sealing up ducts or redesigning ductwork to prevent the cross-spread of air between spaces. You should:

  • Conduct an evaluation of your building’s mechanical ventilation system by doing air flow measurements and camera inspections to determine its condition and vulnerability.
  • Implement a targeted ventilation strategy where your fans exhaust equally to balance the flow of air for each space. Balanced air flow from each register will ensure exhausted air travels to its intended location, helping to prevent transmission between spaces.
  • Hire experienced engineers to design an upgrade to your ventilation system. EN POWER’s engineers have upgraded several hundred mechanical risers to achieve balanced exhaust ventilation. Click here to read about our strategy for improving IAQ and some of our projects.


Frequently Asked Questions (FAQ)


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Can COVID-19 (coronavirus) spread through apartments?

In a well-documented case in 2003, SARS (a virus in the same family as COVID-19) was proven to spread between apartment ventilation systems. In fact, about 33% of the cases in the building were from apartments that were vertically arranged. This is notable since most multifamily buildings have vertically arranged exhaust ventilation systems. If you can smell a neighbor’s cooking or smoking, a virus can be transmitted from one apartment to other apartments.

Is ultraviolet light (Ultraviolet Germicidal Irradiation, UVGI) effective to kill coronavirus?

Yes, but not every product or installation method is appropriate for every application. Certain types of ultraviolet light, UV-C, products have been used in air-handling systems, elevators, and operating rooms to disinfect. However, be sure to discuss your specific needs with lighting experts like EN-POWER so we can analyze what would be effective for your building.

Are filters in ventilation systems effective to prevent the spread of COVID-19? What kind of filters are effective?

Somewhat – but if used as the only mitigation strategy, filters will be ineffective in reducing transmission. Filters in mechanical ventilation systems must be one component of an overall strategy for mitigating the transmission of infectious aerosols. Properly installed high-efficiency filters (MERV-13 or greater) are a line of defense that can be easily implemented; however, our industry is still reviewing their full ability to filter (i.e., contain) COVID-19. Review your air-handling systems’ manuals to determine the highest rated MERV filter that you can install.

HEPA filters installed in portable air cleaners are also a part of the overall strategy for mitigating transmission. Again, they cannot be a sole line of defense, even when installed strategically.

What about other products, like ionizers or ozone generators? Can I use them to reduce infection?

No. Many other products are yet to be proven effective in reducing transmission in real-world applications.

I see COVID-19 transmission can be reduced by increasing air flow in buildings. Won’t increasing fresh air or exhaust ventilation also increase my building’s energy use?

It depends. Implementing a targeted ventilation strategy can reduce overall energy consumption while optimizing how much fresh air (i.e., dilute) is supplied to a building. However, building codes mandate a minimum fresh air requirement and, unfortunately, many buildings bypass fresh air dampers or reduce outdoor air supply in order to control air supply temperatures more easily. In the age of COVID-19, this practice is very ill-advised.

Read one of our case studies to learn how we helped a large multifamily facility reduce their energy bills, while also improving ventilation for all of their apartments.

How can I demonstrate to my residents I’m doing something about COVID-19?

Work with a qualified engineering consultant like EN-POWER to implement a strategy of Clean-Dilute-Contain (CDC) to help prevent the spread of COVID-19 in your building. EN-POWER can provide handouts to share with your residents describing what you’re doing to help keep them safe.

What should you do next?


Integrating CDC (Clean-Dilute-Contain) strategies into building operations is how we will start to build resiliency in our built environment. We at EN-POWER GROUP are collaborating with trade leaders and technical committees in order to support our clients through the COVID-19 paradigm. Reach out to us if you have any questions about how to implement these strategies in buildings.