Hi folks, as states begin to "open back up" following widespread shut downs due to COVID-19, we understand that several programs are disallowing the use of blower door testing moving forward due to the (obvious) concerns presented by moving a large amount of air around, which the coronavirus seems to really like. I was wondering if there had been any discussion, either with BPI or any other organization, about providing specific guidance on this issue?  For example, not conducting blower doors may conflict with WAP guidelines but frankly it does not yet feel safe to use a blower door in occupied spaces, particularly in those dwellings that may be more dense than single-family housing.

Thanks for your consideration...

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  • Hello,

    There is a reference to a document we had posted to our website in the conversation below.  We have been refining the document and there is a new one posted to our website.  https://energyconservatory.com/blower-door-testing-during-covid-19-...

    I wish I could tell you it provides "The Answers"  - but it does not.  That said, it supports the general discussion and comments made by Paul related to each person should assess risks and their tolerance.  It also agrees that the risks (for tester and occupants) for single family homes with no shared walls to other envelopes can be understood fairly well.  It also offers a couple of suggestions for how to minimize risk during a test and a reminder to disinfect equipment per CDC guidelines between homes.  Hope it helps frame up some context as people make decisions...

    Blower Door Testing During COVID-19 - Guideline from TEC Minneapolis - The Energy Conservatory | Bl…
    Blower Door Testing During COVID-19 We have had quite a few people ask us about testing during the COVID-19 pandemic.  We are not qualified to say wh…
  • Emily,

    Thank you for raising this question for the community. The Building Performance Association will be issuing a statement shortly, based on the best available scientific evidence and guidance. Spoiler alert, a blower door test in a single family home is not expected to pose any health risk to either the residents or the assessor. In fact, using the blower door to flush the home with outside air prior to running the test is recommended. This does not address concerns of the assessor entering the home in the first place, which is a separate issue.

    Also, many organizations are creating comprehensive guidance for "openning back up". The Association is reviewing several of these documents and trainings and will post links as well as compare/contrast. Importantly, the ad-hok committee doing this work is linking recommendations to primary sources, such as CDC guidance, so that professionals can make informed judgements and can track updates as CDC, OSHA and others update their recommendations.

    Best regards,


  •  Thanks all.  I appreciate the resources that have been shared from TEC and elsewhere.  I would be interested in a paper if Paul is working on one, or if anyone else develops a policy they are willing to share.  In the meantime, great discussion!

  • Hi, Emily,

    NASCSP is collecting a lot of resources: https://nascsp.org/coronavirus-resources/ including several states' safe back to work plans and protocols for others to draw from.

    I don't want to downplay the severity of the pandemic, but I believe in terms of BD testing, the issue has become muddied. This is by and large a worker safety issue. If we begin with the assumption that we wouldn't be entering homes with confirmed infections, and that anyone could be an asymptomatic carrier, we have these facts:

    • If anyone in the household is shedding virus, there is almost no way to prevent household transmission unless severe control methods are taken (which they wouldn't be doing if they didn't know they were infected, and if they did know they were infected, we wouldn't be entering the home in the first place).
    • Ventilating the home (removing any airborne particles) is absolutely the best thing we can do for worker safety - it won't harm the clients or prevent household transmission for reasons mentioned above.
    • As long as everyone, including residents, wears face coverings prior to running the BD, that will greatly reduce the introduction of additional virus particles into the home during the energy audit.
    • As long as everyone stays out of the fan flow, it's unlikely they would be at increased risk of infection. But several workers wear full PPE and either flush the home first (by running BD with windows open) or conduct the test from outside, bringing the residents outside, too. The discussion re: pressurization vs. depressurization continues.

    Over the course of several discussions with my network, we have landed on the general consensus of: No BD testing without a policy, and here are elements of a solid policy. Very few are advocating halting BD testing but continuing with work. If we are that concerned and can't develop safe work protocols, we probably shouldn't be entering people's homes, so should hold off on assessments and production until a policy is crafted (at whatever level).

    I know this isn't exactly answering your question, but thought it might be helpful if you end up in the position where you are part of a team developing policies/protocols.




    Coronavirus Resources
    • This is great, thank you Kelly.  I am in agreement that this is primarily a worker safety issue.  I hear what Paul and the others are saying, but I also know that this novel coronavirus is more contagious than many other viruses we know about, and whose behavior is more well-documented. This discussion is definitely helpful.

      • I have drafted a short/sweet position statement on this issue that I have sent to a couple of people for internal review.  I do continue to wonder what people think the blower door would do that would be the difference between being safe in a home and not.  I agree with Kelly - if we are concerned enough about the blower door then we are probably too fearful to be going into homes and doing anything else.

        • Paul, to this statement, "I do continue to wonder what people think the blower door would do that would be the difference between being safe in a home and not." I don't know how valid it is, but the concern I've heard is that it could stir up or otherwise reintroduce virus particles to an airborne status that had previously settled. Someone mentioned it on our last trainers' call as a liability issue. I'd be interested, as well, to hear if there are any other specific concerns. 

          And look forward to reading your short/sweet paper when it's ready.

          • Yes, I had to leave the call before getting into that discussion.

            Given that the virus is viable for not more than a few days on any surface (with many surfaces being hours) then what we are talking about here is concern about cases where there is an asymptomatic person in the home but who does have the virus.  If that is the case then the indoor air (where the virus can survive for a few hours) also contains the virus.  This is part of why wearing masks is so important.

            If the air has virus in it then the best thing we can do is purge it as quickly as possible.  The way that the virus has "stuck" to surfaces may make it more or less hard to re-suspend the virus, but if we have enough airflow veloicty over the surface to cause resuspension then we will essentially get it back into the air and it will make its way to and out the fan.  So, again, don't sit with your face right in front of the fan.

            I understand people's fears.  This virus has been horrible and we should absolutely take it seriously.  But I do not see the science being consistent with not doing blower door tests.

            I may need to add some to my short/sweet paper to make these additional points.  That will make it a medium-length/sweet paper.  :-)

            • Hi Paul and Kelly, thanks for the informative and engaging discussion. 

              I work for a WAP agency in Bellingham, WA. Personally, I agree with you Paul - the benefits of removing stale/possibly virus containing air from the home with the blower door definitely seems to outweigh the risks. 

              At this time, our program is opting not to do Blower Door tests, primarily to avoid overall time spent at cleint's house, and the time required to move and disinfect the equipment. Personally, the safety of time savings seems overall latteral or equivalent to the safety gains of running the blower door to change out the air in the house - it doesn't seem like there's enough data right now for this to be anything more than a judgement call by individual agencies. 

  • Let's assume that we are only going to homes if people are not knowingly infected.  A blower door can basically purge the entirety of the indoor air in 2-3 minutes.  Seems like a good thing, yes?  I understand that there may be concerns in attached dwellings, but I have yet to understand what the real concern is for single-family detached.  Just don't stick your face right in front of the fan.

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