April 25 , 2012

The U.S. Department of Energy (DOE) published a Request for Information (RFI) on Building Energy Codes Cost Analysis (Docket No. EERE

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- 0046 ) 1 in the Federal Register on September 13, 2011. (76 FR 56413.) The notice sought public input on how DOE may improve the methodology DOE intends to use for assessing cost

- effectiveness (which includes an energy savings assessment) of changes to residential building energy codes. DOE supports the development of the International Code Council’s (ICC) International Energy Conservation Code (IECC), the national model code adopted by or forming the basis of residential energy codes promulgated by a ma jority of U.S. states, as well as other voluntary building energy codes. DOE performs a cost

- effectiveness analysis of proposed modifications to the codes as part of that support. DOE also performs an analysis of cost

- effectiveness of new code versions. 2

The RFI identified several specific areas for public comment. In response to the comments received, DOE revised the methodology by which DOE intends to assess quantitatively the energy efficiency and cost

- effectiveness of residential energy codes

. DOE h as modified the methodology in several areas to improve overall energy and economic calculations

. Careful consideration was given to each public comment. While many responses to comments are reflected in the cost analysis methodology, not all comments, including those beyond the scope of this r equest, could be accommodated. S ignificant changes can be summarized as follows : Climate Locations : DOE originally proposed to use 15 climate locations in its analysis , representing the various code climate zones and moisture regimes. DOE is expanding the number and distribution of weather locations to include a set of 119 locations , providing more specific geographical coverage , and allow ing aggregat ion directly from state

- level results to both zonal and nationa l averages. Weather Data : The RFI proposed reference to revision 2 of Typical Meteorological Year data (TMY2) for its energy simulation analyses. DOE will use TMY3 data files, based on more recent record years than previous revisions. Multi

- family Protot ype Building : The originally proposed methodology assumed a two

- story multi

- family building. Public comments indicated a three

- story prototype may be more representative of the average multi

- family building . T he methodology was modified to accommodate t his request. Replacement of Efficiency Components : The originally proposed methodology made no explicit assumptions surrounding the replacement of features over the life of the analysis

. DOE is expanding the methodology to account for these replacements through a like

- for

- like assumption

. Measures with a service life less than the overall analysis period will be assume d replaced with pr oducts of identical efficiency.

1 Federal Register Docket: http://www.regulations.gov /#!documentDetail;D=EERE

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- 0001 2 Additionally, DOE is statutorily required to evaluate whether updates to the IECC would result in increased energy savings as compared to the prior version. (42 U.S.C. 6833(a)(5)(A)) The statutorily requi red determination is based solely on an assessment of energy savings. To the extent a quantitative analysis would be required for such a determination, DOE would rely on the energy savings portion of the methodology.Mortgage Insurance : The RFI did not include the expen se of mortgage insurance. Comments

indicated this type of insurance may be required when less than a 20% down payment is applied. As the methodology proposed only a 10% down payment, a modification was made to include this insurance expense within the ca lculation.
The DOE methodology is based on a life

- cycle economic assessment over the life of the building. The assessment will also analyze cash flows and payback periods from the homeowner perspective, in addition to an estimate of energy savings. DOE i ntends to use this methodology to evaluate impacts of existing codes, as well as in proposing future code changes. National analyses will include an estimate of energy savings. In addition, state and zonal analyses will in clude the econo mic assessment. The DOE methodology will also be updated over time to accommodate significant changes, such as shifting economic conditions and the availability of newer data sources.

The residential cost analysis methodology is available on DOE’s energy codes website 3 . A pplications of the method are expected to be posted in the following weeks , includ ing assessments of the 2009 and 2012 editions of the IECC , followed by ongoing concepts DOE is investigating for potential in the 2015 IECC code cycle.
For additional information or questions, p lease to contact Michael Erbesfeld ( michael.erbesfeld@ee.doe.go v , ( 202 ) 287

- 1874 )

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Building Energy Codes U.S. Department of Energy

3 DOE Building Energy Codes website: http://www.energycodes.gov/development/residential