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Pressure Pan and Room To Room Pressure Diagnostics
Pressure pans can be your best friend and can work wonders in home performance diagnostics. You can get insight into weird air barriers and attic connections without ever having to remove drywall. Want to know if air sealing is cost effective but don’t want to shoot arrows in the dark by tearing out massive amounts of drywall to find leaks you aren’t even sure where the source is coming from? Turn to pressure pans and room pressure diagnostics.
This can be messy but only because the house connections are “messy,” the basics remain the same in every home. The idea is we always depressurize a home to -50 Pa WRT the outside and if we measure one zone to be -40 Pa, the other zone (that is not measured) is the difference between the two (50 - 40 = 10 Pa). If you measure zonal pressures to be -38 Pa, -39 Pa, -41 Pa and -38 Pa all along the same archway that spans the length of the house that tells you the archway likely has one large air barrier on top of it. If you measure another soffit in the kitchen that has a zonal pressure of -25 Pa, that soffit is likely not connected to your hallway archway soffit. However if you measure a wall chase along a corner bedroom to be -40 Pa, that may be the same air barrier as your archway. Now you can draw an air barrier map for your install crew or for a third party contractor so they know exactly where to remove drywall or look in the attic to cap and seal the connections. Zonal pressure become even more useful in balloon framed 3 story houses with cubby closets where there is no accessible attic and you need to rely on pressure mapping to find which walls are inside, which are outside and which ones are connected. By constantly practicing, being curious and taking those extra readings you will start to become a zonal pressure expert and truly help your clients in tight situations. Unfortunately, there is no short cut here; you just need to stay curios and practice, practice, practice.
3a. Applied diagnostics and troubleshooting