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Envelope test for modular homes in Texas

Archerenergy | Posted in General Questions on

What ach is Texas requiring on modular homes? This is the thermal envelope test or blower-door test.

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  1. GBA Editor
    Martin Holladay | | #1

    Here is a link to a statement on blower-door test requirements in Texas, dated April 17, 2017. I don't see any reference to an exception for modular homes.

    "The 2015 IECC now requires residential occupancies, including detached one- and two-family dwellings and multiple single-family dwellings (townhouses) as well as Group R-2, R-3 and R-4 buildings three stories or less in height, to pass a blower door test. A FINAL INSPECTION CANNOT BE PASSED WITHOUT A TEST REPORT DEMONSTRATING COMPLIANCE.

    "IECC 402.4.1.2 – Testing. Blower door test required. The test is performed after the building is installed. The building or dwelling shall be tested and verified as having an air leakage rating not exceeding the following:
    • Five air changes per hour in Climate Zone 2
    • Three air changes per hour in Climate Zones 3 and 4.
    The test shall be conducted in accordance with ASTM E 779 or ASTM E1827 and reported at a pressure of 0.2 inch w.g. (50 Pascals)."

  2. Archerenergy | | #2

    Very helpful....THANKS...Any requirements for the duct test?

  3. GBA Editor
    Martin Holladay | | #3

    Google is your friend. You can often use Google to answer this type of question.

    Here is a link to a Texas-specific article which should help you: HVAC System Duct Sealing and Testing.

  4. Expert Member
    Armando Cobo | | #4

    Texas is a “home rule” state, so it allows local jurisdictions to make amendments to the energy code, so long as the change does not result in a less stringent code. To amend the state code in non-attainment and affected counties (Read- most populous counties), Energy Systems Laboratory (ESL) of Texas A&M University must first determine whether the amended code is as stringent as the existing state code. Code amendments that are determined to be as stringent as, or more stringent than, state code may be implemented through local ordinance. This authority also allows a local jurisdiction to implement a newer version of energy code, so long as that code is more stringent than the state minimum.
    In North Texas, the North Texas Council of Government, at the request of the building industry, changed the air tightness requirement to ≤4ACH50 from ≤3ACH50, wall insulation to R13+3 form R13+5, but it upgraded the attic insulation to R49 from R38. All this happened because the 2015 IECC “is too hard”.
    The reality is that builders use ≤4ACH50, R13 wall insulation and R38 in the attic and often do not use a HERS Rater. The aggravating part is that building inspectors, raters and verifiers are passing those homes. All of us that work in the efficient housing market in NTX have to deal with all the unethical and corrupt industry.

  5. Expert Member
    Peter Yost | | #5

    Armando has it right: see the "Code Change" tab here:


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