Don’t Be Spooked by RESNET® Chapter 8 on Windy Days

Have you ever done a blower door test on a windy day and the reading jumps around?  Kinda spooky sometimes what pressures can do to a house.spooky house

Some of the typical workarounds were to use the time average function, or set the blower door in a door to the garage (with overhead door open) and do your best to guess which reading you should take.

Those days are over! Earlier this year RESNET released changes to Chapter 8 that requires 5 baseline readings with time average of 10 seconds each and no more than a 10 Pa range in order for a test to comply with single point procedures.

Everyone should take the time to download the appropriate software for their equipment.  You are not required to use the software if your tests meet the criteria above and your elevation is less than 5000 feet, and the temperature difference between inside and outside is less than 30 degrees.  Otherwise you are required to use a RESNET approved software program for adjustments to your results.

If you ever come across these scenarios it would benefit you to comply with RESNET and download the software to your computer and think about how this fits in your process.  The following are the most commonly used programs approved for RESNET testing.  If anyone has other suggestions please feel free to provide…Blower Door Test

These programs will also have the ability to run the above single point test automatically and take the thinking out of doing the baseline readings. This will streamline your process and make sure you’re prepared for when the single point is not allowed due to windy conditions.

In the case that a home fails the single point criteria you have many options.  Here are a couple:

  1. You can run the multipoint test with an automated setup using your computer and various connections.  A report is issued with an adjusted CFM50 based on the results.
  2. If the automated test is not an option (for whatever reason), you can manually take the required CFM results at various pressure readings in accordance with the RESNET procedures. Then manually plug those readings into the software to get your adjusted reading.

Please see the attached 2 pager on this procedure from the RESNET standards HERE.  I’d recommend printing this out and including it in your kit if you don’t have the right setup for automated multipoint.

On a side note, did you know that the wind can affect the rotation of the earth? 

Glenn Pease

Glenn Pease
EPS Program Manager
EnergyLogic, Inc.



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