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From the Rev. Dr. Dennis S. Tierney, Property Manager

“Breathe on me, Breath of God,
Fill me with life anew,
That I may love what Thou dost love,
And do what Thou wouldst do.”
(Edwin Hatch, 1878)

In July 2020, the diocese prepared and distributed a document about safe practices for churches to follow about air quality in a time of COVID-19. This document updates that information. It is based on a webinar on Indoor Air Quality that was held on July 26, 2021, sponsored by Sheet Metal Workers Union and the National Energy Management Institute and subsequent research.

Air quality matters always, but especially indoors. Adequate ventilation requires mixing new outside air with existing indoor air to provide sufficient oxygen to maintain health and attention on the part of the people gathered. Inadequate ventilation can reduce attention levels and even endanger health over time. Most indoor spaces require enough air circulation to keep CO2 levels below 1000 parts per million. Air circulation is obtained either by opening windows or by introducing outside air through the HVAC system.

Photo by Sigmund on Unsplash

All churches, regardless of the type of HVAC system, can monitor the levels of CO2 by purchasing CO2 monitors. They can be mounted inside the gathering space and will give the ambient levels of CO2. Such monitors are available on-line and cost about $100. One monitor could be used to establish baseline data for several gathering spaces on a church campus.

If a church has a forced air circulation system, the amount of outside air can be increased by adjusting the system. This does increase heating costs, so the amount of outside air admitted to the system needs to be balanced against heating and cooling costs.

Churches with forced air systems should review their filter systems. Air filters come with ratings stated as MERV which stands for Minimum Efficiency Reporting Value. The higher the MERV number, the better the filtration. The presenters at this webinar recommended that churches increase the MERV rating to 13 or higher if their system can accept the higher rating filters. Filters with ratings above 13 are generally only found in surgical operating suite HVAC systems and require special fan systems to prevent damage to the system. It should also be noted that all filters, regardless of MERV ratings must be changed regularly to remain effective.

If a church has a non-forced air system, either radiators or radiant heating, then the amount of outside air can be regulated by opening windows as necessary. Should a church without an air circulation system wish to filter its air, it will need to purchase a portable filter – either a HEPA filter or one with a high MERV rating. The challenge to these systems is the amount of air that can be cleaned. Churches should be careful about matching the machine to the size of the space. These machines work better in ordinary rooms than they do in large spaces like sanctuaries.

Adding a HEPA (High Efficiency Particulate Air) filter machine can improve air quality by removing particulates as small as 0.1 microns. These machines vary in size and noise level but there are machines that can clear a large room (1,600 square feet) in 30 minutes. Some are portable so that one device could be used for multiple purposes. HEPA filters must be changed regularly to maintain the efficacy of the machine.

The current medical data on the size of COVID particles is complex and not completely known. It does appear that some COVID particles are small – less than a micron and, therefore, more prone to remaining in the air than larger particles do. Removing very small particles appears to require a HEPA filter. While no air filtration system is perfect, the percentage of COVID particles in the air can be reduced by good HVAC systems and HEPA filtration devices. A general review of prices for HEPA filter machines suggests a price range under $1,000. One key is selecting a machine large enough to handle a church sanctuary. Measure the dimensions of your worship space to get the number of square feet and then choose your machine accordingly.

Photo by Alex Perz on Unsplash

Finally, churches can obtain professional assessments of indoor air quality by hiring a qualified contractor to perform a site evaluation. These typically cost between $500 and $1,000 depending on the square footage involved or the complexity of the building or buildings involved.

The webinar recommended TABB – Testing, Adjusting, Balancing Bureau, a professional organization of HVAC companies that perform diagnostic tests on air quality. Their website is

In addition to COVID-19 concerns, air quality issues have increased due to climate change. Forest fires appear to be a recurring matter in many communities, and air pollution is also a problem in many communities.

Attending to the air we breathe is a matter for us all. There is only one atmosphere on our planet. Air is no respecter of national or state or community boundaries. We all share one planet; we all share one atmosphere; we all breathe air that is common to us all.

Breathe on Me, Breath of God – Reflections on Safe Church Ventilation in COVID-19 Time (Updated for 2022): An Occasional Paper on Property Management in the Diocese of Olympia Series

2 thoughts on “Breathe on Me, Breath of God – Reflections on Safe Church Ventilation in COVID-19 Time (Updated for 2022): An Occasional Paper on Property Management in the Diocese of Olympia Series

  • February 26, 2022 at 12:23 pm

    Thank you for this information. It seems all businesses would benefit from it as well. It would be a true blessing if it could be disseminated to everyone.
    You explained it so clearly . I appreciate you.

  • February 26, 2022 at 4:28 pm

    UV lights are recommended too, and can be inside air ducts or mounted on a wall.

    ( My field is structural inspections, but have experience with moisture-dection and with air-tightness of building envelopes. )

    We are former members at Trinity Seattle, now at Epiphany in Madrona due to Youth Program.


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