M e m o r a n d u m
FROM:
Michael Baker, SBW
TO:
RTF Staff
DATE:
February 11, 2013
RE:
Phase I Review and Update Recommendations: New Single Family PTCS Ducts Inside
This memo documents the results of DNV KEMA’s detailed review of the UES (Unit Energy Savings)
measure New Single Family PTCS Ducts Inside. This measure has been categorized by the RTF as Proven,
and therefore this memo outlines recommendations consistent with that category. This measure covers
savings from placement of the ducts within the thermal envelope in new construction single family
homes. The measures must be installed in accordance with Performance Tested Comfort Systems
(PTCS) Duct Program specifications. The review focused on the derivation of the measures’ Unit Energy
Savings (UES) and associated documentation.
Summary Recommendation. The status of this measure should be changed to Under Review.
The following recommendations lead to a change in status to Under Review.
1. Workbook needs to be updated to use latest ProCost template which includes Measure Cost and
EUL summary sheets.
2. Verify that the “HCA3” equipment description (7.9 HSPF / 13 SEER) on the “SEEMinput.”
worksheet is correct and revise if it is erroneous.
3. Document the source(s) of the PTCS Heat Pump Control Strategy Weights parameter.
4. Document the source(s) of the Duct Leakage parameters used in the SEEM simulations.
5. Document the source(s) of the Internal Loads and Infiltration parameters.
6. Fill in the UES unit description on the “LookupTable” worksheet.
7. Re-run the measures using SEEM94.
Limitation of Review. We accepted without review the characteristics of the calibrated SEEM models
and the associated climate weighting methods. The SEEM model was not reviewed internally.
Note: The input parameters (worksheet “SEEMinput”) and the workbook’s manipulation of the output
data (worksheets “SEEMoutput” and “Analysis”, and macro “hpmid2”) were reviewed to check for
calculation and consistency errors as well as to document the associated climate and heat pump control
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weightings (external of the SEEM model) and the change in supply and return duct efficiencies between
baseline and measure UEC parameters.
Alterations to Workbook and Documentation.

A sheet called “Summary” has been added to the workbook. This sheet describes how measures
are identified, lists important constants and their sources, describes the savings estimation
algorithm and the associated baseline and efficient case parameters and their sources for each
measure and UES component.
Recommendations for Updates. The RTF should implement the following recommendations:
1) Workbook Structure and Formulas
a) Update workbook with latest ProCost template to include Measure Cost and Effective Useful
Life (EUL) summary sheets. This deficiency causes the measure status to change to Under
Review.
b) The input values used to interpolate an HSPF value of 8.5 need to be verified. The SEEM input
table on the “SEEMinput” worksheet shows a description for the “HCA3” equipment type as
“HSPF7.9/SEER13”; however, the “Analysis” sheet cell equations that use the “hp2mid” macro
(Cells C91:G93 and Cells C100:G102) use an HSPF value of 7.7. Based on the SEEM run names, it
appears that this may just be a typo for the equipment description of “HCA3”. If this is the case,
change the equipment description of “HCA3” to “HSPF7.7/SEER13”. Otherwise, since the SEEM
model used HSPF 7.9; the “hp2mid” macro should also use the value 7.9 as the “low” HSPF input
in order to interpolate correctly. This deficiency causes the measure status to be Under Review.
2) Documentation
a) Document the source of the PTCS Heat Pump Control Strategy Weights. The documentation can
be placed on the measure’s Summary worksheet, under the “Further Explanation and Sources”
section. The PTCS Heat Pump Control Strategy Weights are listed in the SEEM Runs workbooks
(ExistingResidentialManufacturedHome_SEEM94Runs_03a.xlsm, for example) on the
“Constants” worksheet. This deficiency causes a change of status to Under Review.
b) Document the Duct Leakage parameters used in the SEEM simulations. It appears that the
parameters are based primarily on a 2007 study (Residential New Construction Characteristics
and Practices Study, pp 115-117 (NEEA, 2007)) but were modified by Ecotope based on
assumptions. All assumptions and reference sources used should be clearly documented with a
summary of analyses performed, if available. This deficiency causes a change of status to Under
Review
c) Document the source of the Internal Loads and Infiltration parameters. The documentation can
be placed on the measure’s Summary worksheet, under the “Further Explanation and Sources”
section. This deficiency causes a change of status to Under Review.
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3) Measure Definition
a) UES unit description is missing from the “Lookup Table” worksheet, Cells F3:F8. Based on the
model run outputs on the “SEEMoutput” worksheet and calculations on the “Analysis”
worksheet, it appears the active unit is per single family home. Recommend adding the UES unit
description to the look up table to provide clarity. This deficiency causes a change of status to
Under Review
4) UES Savings Estimation Method
a) No changes recommended
5) Input Parameters
a) The measures should be re-run in SEEM94 so that previously used SEEM model runs can be
retired. The review found that this newer version of SEEM (v.0.94 – SEEM94) with updated
infiltration values was approved for use by the RTF on December 13, 2011. This deficiency
causes a change of status to Under Review
Additional Considerations.
1) The measure currently reflects baseline HVAC equipment of a heat pump with a rating of 8.5 HSPF.
This value was established using Energy Trust of Oregon's 'Air Source Heat Pump Market
Transformation Model Development and Market Research. Prepared by Summit Blue Consulting,
LLC. December 29, 2009' and is intended to represent a typical installation when incentives are not
available. The report indicates that the relative percentage of units sold with the different heating
efficiency levels fluctuated up to 10% year of year. Additionally, Energy Trust of Oregon’s ‘Process
Evaluation of the 2009-2010 New Homes Program; prepared by Research Into Action, Inc.
September 2, 2011’ report suggests that builders very often (71%) install high-efficiency HVAC
equipment to meet or exceed new home code. These reports suggest that high efficiency heat
pumps are growing in the new home construction market share and that the heating efficiency
levels for new home construction are consistently rising. That being said, a May 5, 2009 RTF meeting
included a presentation on the Ducts Inside measure savings and showed that savings are very
similar between a SEEM model with a 7.7 HSPF without PTCS controls heat pump and a SEEM model
with a 8.5 HSPF with PTCS controls heat pump. Reevaluating the HVAC Efficiency to ensure the
baseline heat pump heating efficiency level represents a typical single family new construction
installation should be considered; however, it is presumed that the UES differences from this
potential update will not be significant at this moment.
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