Foundation Insulation¶
Table of Contents
Determining the primary foundation¶
HEScore permits the specification of two foundations.
The two foundations that cover the largest area are selected.
This is determined by summing up the area of the FrameFloor
or
Slab
elements (depending on what kind of foundation it is).
Area
elements are required for all foundations unless there is only one
foundation, then it is assumed to be the footprint area of the building.
If there are more than two foundations, the areas of the largest two are scaled
up to encompass the area of the remaining foundations while maintaining their
respective area fractions relative to each other.
Foundation Type¶
Once a foundation is selected, the HEScore foundation type is selected from HPXML according to the following table.
HPXML Foundation Type | HEScore Foundation Type | |
---|---|---|
Basement | Conditioned=”true” | cond_basement |
Conditioned=”false” or omitted | uncond_basement | |
Crawlspace | Vented=”true” | vented_crawl |
Vented=”false” or omitted | unvented_crawl | |
SlabOnGrade | slab_on_grade | |
Garage | unvented_crawl | |
AboveApartment | not translated | |
Combination | not translated | |
Ambient | vented_crawl | |
RubbleStone | not translated | |
Other | not translated |
Warning
For foundation types that are not translated the translation will return an error.
Foundation wall insulation R-value¶
If the foundation type is a basement or crawlspace, an area weighted average
R-value is calculated for the foundation walls. The area is obtained from the
Area
element, if present, or calculated from the Length
and Height
elements. The R-value is the sum of the
FoundationWall/Insulation/Layer/NominalRValue
element values for each
foundation wall. For each foundation wall, an effective R-value is looked up
based on the nearest R-value in the following table.
Insulation Level | Effective R-value |
---|---|
R-0 | 4 |
R-11 | 11.6 |
R-19 | 16.9 |
Then a weighted average R-value is calculated by weighting the U-values by area.
The effective R-value of the R-0 insulation level is then subtracted.
Finally, the nearest insulation level is selected from the enumeration list.
Slab insulation R-value¶
If the foundation type is a slab on grade, an area weighted average R-value is
calculated using the value of ExposedPerimeter
as the area. (The units work
out, the depth in the area drops out of the equation.) The R-value is the sum
of the Slab/PerimeterInsulation/Layer/NominalRValue
element values for each
foundation wall. For each slab, an effective R-value is looked up based on the
nearest R-value in the following table.
Insulation Level | Effective R-value |
---|---|
R-0 | 4 |
R-5 | 7.9 |
Then a weighted average R-value is calculated by weighting the U-values by area.
The effective R-value of the R-0 insulation level is then subtracted.
Finally, the nearest insulation level is selected from the enumeration list.
Floor insulation above basement or crawlspace¶
If the foundation type is a basement or crawlspace, for each frame floor above
the foundation, a weighted average using the floor area and R-value are
calculated. The area is obtained from the Area
element. The R-value is the
sum of the FrameFloor/Insulation/Layer/NominalRValue
element values for
each frame floor. The effective R-value is looked up in the following table.
Insulation Level | Effective R-value |
---|---|
R-0 | 4 |
R-11 | 15.8 |
R-13 | 17.8 |
R-15 | 19.8 |
R-19 | 23.8 |
R-21 | 25.8 |
R-25 | 31.8 |
R-30 | 37.8 |
R-38 | 42.8 |
Then a weighted average R-value is calculated by weighting the U-values by area.
The effective R-value of the R-0 insulation level is then subtracted.
Finally, the nearest insulation level is selected from the enumeration list.