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Merge pull request #160 from NREL/assembly_eff_r_values
Adding effective R-value lookup
2 parents e26fcc5 + e5eaf54 commit 5f69767

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‎MANIFEST.in

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recursive-include hescorehpxml/schemas *.xsd
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recursive-include hescorehpxml/schemas *.xsd *.json
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recursive-include hescorehpxml/lookups *.csv
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‎docs/source/translation/zone_floor.rst

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@@ -139,27 +139,25 @@ Floor insulation above basement or crawlspace
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If the foundation type is a basement or crawlspace, for each frame floor above
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the foundation, a weighted average using the floor area and R-value are
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calculated. The area is obtained from the ``Area`` element. The R-value is the
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sum of the ``FrameFloor/Insulation/Layer/NominalRValue`` element values for
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each frame floor. The effective R-value is looked up in the following table.
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calculated. The area is obtained from the ``Area`` element.
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.. table:: Floor center-of-cavity effective R-value
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The floor R-value can be described by using ``NominalRValue`` or ``AssemblyRValue``.
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If a user wishes to use a nominal R-value, ``NominalRValue`` elements for all layers need to be provided.
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Otherwise, ``AssemblyRValue`` elements for each layer need to be provided.
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================= ==================
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Insulation Level Effective R-value
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================= ==================
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R-0 4
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R-11 15.8
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R-13 17.8
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R-15 19.8
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R-19 23.8
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R-21 25.8
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R-25 31.8
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R-30 37.8
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R-38 42.8
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================= ==================
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If nominal R-value is used, the R-value is the sum of the ``FrameFloor/Insulation/Layer/NominalRValue`` element values
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for each frame floor. The nearest discrete R-value from the list of possible R-values for that floor type
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is used to determine an assembly code.
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Then, the assembly R-value of the corresponding assembly code from the lookup table is used.
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The lookup table can be found at `hescorehpxml\\lookups\\lu_floor_eff_rvalue.csv
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<https://github.com/NREL/hescore-hpxml/blob/assembly_eff_r_values/hescorehpxml/lookups/lu_floor_eff_rvalue.csv>`_.
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Then a weighted average R-value is calculated by weighting the U-values by area.
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If assembly R-value is used, the discrete R-value nearest to assembly R-value
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from the lookup table is used. The lookup table can be found at `hescorehpxml\\lookups\\lu_floor_eff_rvalue.csv
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<https://github.com/NREL/hescore-hpxml/blob/assembly_eff_r_values/hescorehpxml/lookups/lu_floor_eff_rvalue.csv>`_.
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When more than one HPXML ``FrameFloor`` element must be combined into one floor
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construction for HEScore, a weighted average assembly R-value is determined by weighting the U-values by area.
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.. math::
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:nowrap:
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R_{eff,avg} &= \frac{1}{U_{eff,avg}} \\
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\end{align*}
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The effective R-value of the R-0 insulation level is then subtracted.
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.. math::
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R = R_{eff,avg} - 4.0
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Finally, the nearest insulation level is selected from the enumeration list.
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Then the discrete R-value nearest to the weighted average assembly R-value from the lookup table is used.
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‎docs/source/translation/zone_roof.rst

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@@ -209,72 +209,42 @@ HPXML v3
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Radiant Barrier
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***************
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If the ``Roof/RadiantBarrier`` element exists and has a "true" value, the attic
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is assumed to have a radiant barrier and no roof deck insulation is assumed
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according to the construction codes available in HEScore.
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If the ``Roof/RadiantBarrier`` element exists and has a "true" value and roof deck insulation R-value is 0,
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the attic is assumed to have a radiant barrier according to the construction codes available in HEScore.
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If the ``Roof/RadiantBarrier`` element exists and has a "true" value but roof deck insulation R-value greater than 0,
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the roof will be modeled as a roof with no radiant barrier.
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.. _roof-rvalues:
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Roof R-value
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************
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R-values for the roof deck are added up by summing the values of the
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``Layer/NominalRValue``. If the roof construction was determined to have
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:ref:`rigid-sheathing`, an R-value of 5 is subtracted from the roof R-value sum
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to account for the R-value of the sheathing in the HEScore construction.
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The roof R-value can be described by using ``NominalRValue`` or ``AssemblyRValue``.
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If a user wishes to use a nominal R-value, ``NominalRValue`` elements for all layers need to be provided.
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Otherwise, ``AssemblyRValue`` elements for each layer need to be provided.
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Starting from HPXML v3, multiple roofs are allowed to be attached to the same
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attic, if the attic has more than one ``Roof`` element with roof insulation, the
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insulation values are combined by first selecting the nearest roof
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center-of-cavity R-value for each roof area from the table below.
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.. table:: Roof Center-of-Cavity Effective R-values
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+-------------------+---------------------+------------+----------+--------------+---------------+
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|Exterior |Composition or Metal |Wood Shakes |Clay Tile |Concrete Tile |Tar and Gravel |
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+-------------------+---------------------+------------+----------+--------------+---------------+
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|R-value |Effective R-value |
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+===================+=====================+============+==========+==============+===============+
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| **Standard** |
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+-------------------+---------------------+------------+----------+--------------+---------------+
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|R-0 |2.7 |3.2 |2.2 |2.3 |2.3 |
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+-------------------+---------------------+------------+----------+--------------+---------------+
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|R-11 |13.6 |14.1 |13.2 |13.2 |13.2 |
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+-------------------+---------------------+------------+----------+--------------+---------------+
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|R-13 |15.6 |16.1 |15.2 |15.2 |15.2 |
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+-------------------+---------------------+------------+----------+--------------+---------------+
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|R-15 |17.6 |18.1 |17.2 |17.2 |17.2 |
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+-------------------+---------------------+------------+----------+--------------+---------------+
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|R-19 |21.6 |22.1 |21.2 |21.2 |21.2 |
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+-------------------+---------------------+------------+----------+--------------+---------------+
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|R-21 |23.6 |24.1 |23.2 |23.2 |23.2 |
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+-------------------+---------------------+------------+----------+--------------+---------------+
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|R-27 |29.6 |30.1 |29.2 |29.2 |29.2 |
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+-------------------+---------------------+------------+----------+--------------+---------------+
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|R-30 |32.6 |33.1 |32.2 |32.2 |32.2 |
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+-------------------+---------------------+------------+----------+--------------+---------------+
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| **w/ Radiant Barrier** |
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+-------------------+---------------------+------------+----------+--------------+---------------+
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|R-0 |5 |5.5 |4.5 |4.6 |4.6 |
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+-------------------+---------------------+------------+----------+--------------+---------------+
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| **w/ foam sheeting** |
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+-------------------+---------------------+------------+----------+--------------+---------------+
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|R-0 |6.8 |7.3 |6.4 |6.4 |6.4 |
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+-------------------+---------------------+------------+----------+--------------+---------------+
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|R-11 |17.8 |18.3 |17.4 |17.4 |17.4 |
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+-------------------+---------------------+------------+----------+--------------+---------------+
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|R-13 |19.8 |20.3 |19.4 |19.4 |19.4 |
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+-------------------+---------------------+------------+----------+--------------+---------------+
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|R-15 |21.8 |22.3 |21.4 |21.4 |21.4 |
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+-------------------+---------------------+------------+----------+--------------+---------------+
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|R-19 |25.8 |26.3 |25.4 |25.4 |25.4 |
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+-------------------+---------------------+------------+----------+--------------+---------------+
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|R-21 |27.8 |28.3 |27.4 |27.4 |27.4 |
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+-------------------+---------------------+------------+----------+--------------+---------------+
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Then a weighted average is calculated by weighting the U-values by area. This averaged Center-of-Cavity Effective
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R value is combined from all roofs attached to the same attic. The highest weighted roof construction type is selected
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to represent properties of the attic.
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If nominal R-value is used, the R-value is summed for all insulation layers. If the roof construction
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was determined to have :ref:`rigid-sheathing`, an R-value of 5 is subtracted from the roof R-value sum
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to account for the R-value of the sheathing in the HEScore construction.
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The nearest discrete R-value from the list of possible R-values for that roof type
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is used to determine an assembly code.
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Then, the assembly R-value of the corresponding
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assembly code from the lookup table is used. The lookup table can be found
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at `hescorehpxml\\lookups\\lu_roof_eff_rvalue.csv
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<https://github.com/NREL/hescore-hpxml/blob/assembly_eff_r_values/hescorehpxml/lookups/lu_roof_eff_rvalue.csv>`_.
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If assembly R-value is used, the discrete R-value nearest to assembly R-value
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from the lookup table is used. The lookup table can be found at `hescorehpxml\\lookups\\lu_roof_eff_rvalue.csv
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<https://github.com/NREL/hescore-hpxml/blob/assembly_eff_r_values/hescorehpxml/lookups/lu_roof_eff_rvalue.csv>`_.
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If the attic has more than one ``Roof`` element, a weighted average assembly R-value is determined
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by weighting the U-values by area.
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Then the discrete R-value nearest to the weighted average assembly R-value from the lookup table is used.
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Starting from HPXML v3, multiple roofs are allowed to be attached to the same attic.
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If the attic has more than one ``Roof`` element with roof insulation,
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a weighted average R-value is calculated using assembly R-value for each ``Roof``,
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whether nominal R-value or assembly R-value is used.
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The weighted average is calculated by weighting the U-values by area.
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.. math::
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R_{eff,avg} &= \frac{1}{U_{eff,avg}} \\
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\end{align*}
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If the house has more than two attics specified, the attics of the same roof
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types are combined. Therefore, the same weighted average calculation is
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performed (taking roof-level averaged R as :math:`R_{i}` and attic area
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determined in `attic area`_ as :math:`A_{i}`) to combine multiple attics.
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Then the R-0 effective center-of-cavity R-value (:math:`R_{offset}`) is selected
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for highest weighted roof construction type for the attic represented in the
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calculation and is subtracted from :math:`R_{eff,avg}`.
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.. math::
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R = R_{eff,avg} - R_{offset}
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Finally the R-value is rounded to the nearest insulation level in the
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enumeration choices for the highest weighted roof construction type for the
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attic is included in the calculation.
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Then the nearest discrete R-value to the weighted average R-value from the lookup table is used.
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The lookup table can be found at `hescorehpxml\\lookups\\lu_roof_eff_rvalue.csv
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<https://github.com/NREL/hescore-hpxml/blob/assembly_eff_r_values/hescorehpxml/lookups/lu_roof_eff_rvalue.csv>`_.
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Attic R-value
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*************
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Determining the attic floor insulation levels uses the same procedure as
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:ref:`roof-rvalues` except the lookup table is different. The attic floor
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center-of-cavity R-values are each R-0.5 greater than the nominal R-values in
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the enumeration list.
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:ref:`roof-rvalues` except the lookup table is different.
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If nominal R-value is used, the attic floor center-of-cavity R-values are each R-0.5 greater
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than the nominal R-values in the enumeration list.
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If assembly R-value is used, the lookup table at `hescorehpxml\\lookups\\lu_ceiling_eff_rvalue.csv
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<https://github.com/NREL/hescore-hpxml/blob/assembly_eff_r_values/hescorehpxml/lookups/lu_ceiling_eff_rvalue.csv>`_
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is used.
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If the primary roof type is determined to be a cathedral ceiling, then an attic
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R-value is not calculated.
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<Walls>
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If an attic has knee walls specified, the area of the knee walls will be added
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to the attic floor area. The knee walls center-of-cavity R-value is R-1.8 greater
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than the nominal R-value. The knee walls center-of-cavity R-value will be reflected
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to the attic floor area.
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The knee walls R-value can be described by nominal R-value or assembly R-value.
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If nominal R-value is used, the knee walls center-of-cavity R-value will be reflected
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in the area weighted center-of-cavity effective R-value of the attic floor.
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This averaged center-of-cavity effective R value is combined from all knee walls
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The knee walls center-of-cavity R-value is R-1.8 greater than the nominal R-value.
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If assembly R-value is used, the knee walls assembly R-value will be reflected in
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the area weighted assembly effective R-value of the attic floor.
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The averaged center-of-cavity or assembly effective R value is combined from all knee walls
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and attic floors attached to the same attic. The highest weighted attic floor
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construction type is selected.
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construction type is selected.
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