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Positive Pressure and Humidity in Attic

suect | Posted in General Questions on

I was advised by an energy rater that I have positive pressure in the home through taking measurements of the supply registers and return registers on our one story home in Texas.  He stated this may lead to moisture in the walls as well as the attic.

I have consulted our HVAC company that did measurements alone just prior to the filter and then in the supply. His conclusion is the measurements are fine.

My observation is the humidity and temperature in the foam insulated attic is similar during inactivity or limited HVAC activity, but as it begins to work more frequently the humidity climbs in the attic.  I am also noticing a subtle odor.

main level humidity is 48-52% throughout the day and night. Attic humidity is up to 62% when it climbs.

Something seems off to me, I sense the energy auditor is onto something.  Any thoughts?

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  1. walta100 | | #1

    To my ear it sounds like you are trying to have your cake and eat it too.

    It sounds like you started to condition your attic but stopped after you insulated the roof but before you removed the old insulation from the attic floor and connected the attic air to the house air.

    You need to connect the attic and house enough that both have similar temp and humidity readings.


  2. suect | | #2

    The home was insulated originally with foam. I purchased this and have noticed a differential between the two areas.

    Trying to get assistance locally but there are mixed opinions as to the cause.

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