Returning to Church

Hi All,

I volunteered to be co-chair of my church's "returning to church" committee. (I'll never learn!) We are following state and national guidelines, and will probably start with meeting outside for services. But I want to help us prepare for the day when we will move back inside for worship.


The church is Peace Lutheran in Danville, California. Hot and dry climate. It is a big, well lit, open space. It has great acoustics and the space is used for choral group performances, jazz concerts, and art shows. At capacity, I think it could hold about 250 people. I'm sure there will be 50 at most when we return to the building for worship.

My question is this: How can we adjust the HVAC system to move virus particles away from people and to the outside? I've read some case studies of churchs and restaurants and I know that without proper ventilation, the virus particles can migrate from one section/group of people to another and stagnate for a time. I understand that the amount of particles in the air and the time of exposure are the critical elements in determining if one will be infected. An hour or two in a restaurant or church with bad ventiation can lead to multiple infections.

I'm thinking that the position and capacity of the supply and return vents is crucial. I've been writing and editing articles about building science in Building Performance Journal (formerly Home Energy) for a couple of decades, but I'm no HVAC expert. 

What do you think? If it were your meeting hall—for worship, a wedding, family reunion—what would you do?

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  • Jim, IAQ Radio just posted this interview with Bill Bahnfleth, Penn State Professor & ASHRAE Past President. Bill is the chair of ASHRAE's new COVID-19 taskforce and Penn State's facilities staff are relying upon him for Covid19 compliance guidance. They're grappling with the same issues you have with your church.

    IAQ Radio - Episode 586 Blog - Bill Bahnfleth, PhD, PE – Penn State Professor & ASHRAE Past Preside…
    ASHRAE Pandemic Task Force, Mechanical Systems and Covid19 Bill Bahnfleth, PhD, PE is a professor at Penn State University, a past president of ASHRA…
  • Thanks Diane, I'll pass this on to our committee.

  • Jim, Healthy Indoors Magazine has been running a series of articles and video shows about the various aspects of dealing with the COVID-19 pandemic.  You can access those at

    COVID-19 Archives | Healthy Indoors
  • Can we say way to much missing info... how is your system setup now, layouts, package system or???

    In reality there should be no stagnation, air should be flowing everywhere especially when the place is packed. As for viruses - unless you are exhausting all that conditioned air out, it will recirculate. You want to catch it with a filter where the particles will die or maybe consider UV. But that all gets down to what you have & how it is laid out. 

    • Yes, you can say there is too much missing information. I'll dig for some details.


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