do trade-offs improve energy efficiency

Executive Summary

Flexibility vs Mandatory RequirementsThe intent of the International Energy Conservation Code (IECC) is to provide flexibility for the use of innovative approaches and techniques to achieve the objective of effective use and conservation of energy over the useful life of buildings. However, the intent is often overcome with mandatory requirements that remove the flexibility promised.

ReactionsWe usually find one of three reactions from adopting jurisdictions to address mandatory requirements within the IECC:

1. Adopt and ignore2. Adopt and amend3. Adopt and enforce

Performance-based Trade-offsPerformance-based trade-offs have been in the International Energy Conservation Code since the 1998 edition. From 1998 through 2003, the IECC provided for the use of a performance-based compliance path using an annual energy use limit established by Standard Reference Design specifications. A Proposed Home was then compared to that Standard Reference Design to demonstrate compliance. In the 2006 IECC, this was incorporated as a cost-based approach using the Standard Reference Design to produce an annual energy use budget that the Proposed Home could not exceed. Infiltration testing was an option in the 2009 IECC that became mandatory in the 2012 IECC. In both the 2009 and 2012 IECC, the use of high performance mechanical systems to achieve compliance for the performance path was eliminated. The cost savings produced by efficient mechanical systems were accounted for in establishing new federal minimum efficiency standards that go into effect in 2015, but those savings are completely ignored when using the current cost-based performance approach in the 2012 IECC.

The AnalysisIBS Advisors was asked to determine if proposed performance allowances for the 2015 IECC would reduce the intended energy efficiency achieved in the 2012 IECC prescriptive compliance path. To assess this impact, over 100 computer simulations were generated on five proposed revisions (RE72-13, RE109-13, RE116-13, RE166-13, and RE170-13) on homes in 19 cities across the 8 climate zones, comparing the energy efficiency produced by the proposed revision of the IECC to that of homes built to the specifications found in the 2012 IECC Standard Reference Design. All five proposals demonstrated either the same or more energy efficiency than homes built to the 2012 IECC performance path.IBS Advisors, LLC! Do Trade-Offs Improve Energy Efficiency?

2

Introduction

The purpose of the building codes is to “establish minimum requirements to safeguard the public safety, health and general welfare through affordability, structural strength, means of egress facilities, stability, sanitation, light and ventilation, energy conservation and safety to life and property from fire and other hazards attributed to the built environment and to provide safety to fire fighters and emergency responders during emergency operations.”1 The International Energy Conservation Code (IECC) further states “This code shall regulate the design and construction of buildings for the effective use and conservation of energy over the useful life of each building. This code is intended to provide flexibility to permit the uses of innovative approaches and techniques to achieve this objective.”2

The challenges of improving energy efficiency in buildings are many, ranging from increased costs of materials, lack of skilled installers, increased labor costs when you do find skilled installers to the additional costs of administration, verification and documentation- all while balancing those additional costs against the housing market recession, the credit market crunch, mortgage industry overhaul, and an increasingly regulatory environment.

The energy code offers three ways to comply: the prescriptive path using the values in Table R402.1.1, the Total UA alternative using Table R402.1.3, or the performance path found in Section 405 which establishes an annual energy budget based on a Standard Reference Design that the proposed home may not exceed. All three compliance paths also require a set of mandatory provisions be met.

Projects that use the performance path to compliance must meet all mandatory requirements in addition to meeting or being lower than the annual energy budget set by the Standard Reference Design, a computer-simulated home that uses specifications from Table R405.5.2(1) of the IECC.

Forcing homes to comply with all the mandatory requirements when using the performance compliance path reduces the amount of flexibility builders have to use

IBS Advisors, LLC! Do Trade-Offs Improve Energy Efficiency?

3

1 2012 International Residential Code®, Section 101.3, http://publicecodes.cyberregs.com/icod/irc/2012/icod_irc_2012_1_par003.htm?bu=IC-P-2012-000002&bu2=IC-P-2012-000019, retrieved September 9, 2013.

2 2012 International Energy Conservation Code®, Section 101.3, http://publicecodes.cyberregs.com/icod/iecc/2012/icod_iecc_2012_re1_sec002.htm?bu=IC-P-2012-000014&bu2=IC-P-2012-000019, retrieved September 9, 2013

http://publicecodes.cyberregs.com/icod/irc/2012/icod_irc_2012_1_par003.htm?bu=IC-P-2012-000002&bu2=IC-P-2012-000019




http://publicecodes.cyberregs.com/icod/iecc/2012/icod_iecc_2012_re1_sec002.htm?bu=IC-P-2012-000014&bu2=IC-P-2012-000019




innovative approaches and techniques to come in at or under the annual energy use budget established by the Standard Reference Design.

For example, total duct leakage testing is mandatory in the 2012 IECC. However, total duct leakage is calculated differently than duct leakage to the outside, and it is duct leakage to the outside that carries a direct energy penalty.

If the concern is about the quality of the duct system installation, total duct leakage would be an appropriate measurement. If the concern is about the impact of duct leakage on the energy efficiency of the home, duct leakage to the outside is the only duct sealing test that provides the needed information.

Total duct leakage test results must be treated as duct leakage to the outside in the modeling software since there is no way to determine how much of the total leakage will be to the outside and how much will leak inside the home’s thermal envelope. This provides an unfair penalty for contractors forced to use total duct leakage measurements for energy code compliance.

The commercial section of the 2012 IECC establishes a baseline efficiency of the commercial Standard Reference Design mechanical equipment, using the current federal minimum standards for the types of equipment proposed. However, that same concept doesn’t apply to residential buildings.

When the Department of Energy evaluates an energy code to determine expected energy savings and cost-effectiveness pursuant to their statutory requirements under the Energy Policy Act (EPACT), the evaluation is based primarily on net life-cycle cost analysis of a code change (defined as the present value of all costs and benefits summed over the period of analysis).3 Under the 2012 residential IECC, the energy savings from high efficiency mechanical equipment are eliminated from consideration, and the focus instead is on improvements to the thermal integrity of the building thermal envelope. However, we are rapidly approaching the point of diminishing returns on building thermal envelope improvements and it is becoming less cost-effective the further we move down that path.

This unforgiving approach to a performance-based compliance path has a direct impact on achieving cost-effective energy efficiency, creates an additional burden on the


4

3 Todd Taylor, Nick Fernandez, Robert Lucas, “Methodology for Evaluating Cost-Effectiveness of Residential Energy Code Changes” (Pacific Northwest National Laboratory, April 2012)

adopting jurisdictions that enforce the requirements, and creates challenges on the verification side.

What Really Happens

If the contractors are denied the flexibility promised in the intent statement of the IECC, the patterns established with the adoption of the 2009 IECC which had mandatory requirements for air leakage and duct sealing will continue. We have witnessed three solutions to the mandatory requirements dilemma when following the performance path.

The first solution is to adopt the code, and ignore enforcing those provisions or delay the implementation for a significant amount of time.

This option clearly will not provide any improvement in energy efficiency and is a disservice to the community and country. It also underscores the difference between adoption and enforcement- a difference experienced far too frequently in the field.

The second solution jurisdictions have taken is to amend the code during adoption and strike the references to mandatory requirements, often substituting another metric for determining compliance such as a rating system.

This option creates another set of challenges beyond the additional cost to amend the code. These challenges lie in the substitutes chosen to demonstrate equivalent levels of energy efficiency. Some jurisdictions use an energy rating system and require the homes meet or exceed a certain level of energy efficiency, while others use national green building programs such as ICC 700, the NAHB National Green Building Program, or the USGBC’s LEED for Homes program. There is also a proliferation of local green building programs that are being used to demonstrate equivalent energy efficiency. Some jurisdictions, such as the State of Texas, allow the Environmental Protection Agency’s ENERGY STAR® New Homes program as an alternative compliance option.

These choices for alternative compliance that substitute for mandatory requirements are a reflection of the need to change these requirements from mandatory to prescriptive so that trade-offs can be used in the performance method in a consistent way that provides flexibility and innovation, while improving the energy efficiency of the home.

The third option is the adoption and enforcement of the code as written, which can increase the cost of construction because of the lack of flexibility to meet the energy


5

budget requirement using innovative approaches and techniques. This can also lead to increased costs to the adopting jurisdiction to both administer and document compliance. The costs to upgrade computer programs, train staff, and track documentation can be significant, according to one code official interviewed,

Performance-Based Trade-offs

Performance-based trade-offs rely on certain requirements in the current (2012) IECC being changed from mandatory to prescriptive. The annual energy budget produced by the Standard Reference Design reflects the prescriptive requirements, so a proposed home using the performance compliance path would still have to use the same or less energy than a home built following the prescriptive or Total UA compliance path.

In order for these trade-offs to be used in the performance path, the measures may be independently verified and tested by persons approved by the code official. This provides the code official with a more rigorous approach, particularly for air leakage and duct sealing, that permits third party verification with the builders bearing the brunt of the implementation costs.

Under the 2012 IECC, the energy efficiency gains produced by high-performance HVAC and service water heating systems are completely ignored, neutralized by the Standard Reference Design specifications having the same efficiency as the equipment installed in the proposed home.

It hasn’t always been this way. The 1998, 2000, and 2003 IECC’s used an annual energy use approach as a compliance path. This approach used a Standard Reference Design with fixed mechanical equipment efficiencies. This provided builders credit for using advanced HVAC and water heating equipment to help them achieve the annual energy use goal.

The 2004 Supplemental IECC and the 2006 IECC incorporated that same philosophy into the simulated performance alternative. This approach had mandatory requirements for airsealing, but no testing was required. There were also mandatory requirements for HVAC systems, duct insulation and airsealing, pipe insulation, dampers on ventilation systems, and HVAC sizing. No duct testing was required. These codes also established a cost-based energy budget for the proposed home based on the Standard Reference Design which included in the specifications for mechanical equipment the prevailing federal minimum efficiencies.IBS Advisors, LLC! Do Trade-Offs Improve Energy Efficiency?

6

The 2009 and 2012 IECC used the same cost-based approach to energy performance, but neutralized efficiencies gained by installing advanced HVAC and service water heating systems. This approach has led to many jurisdictions reacting to the inflexible requirements by adopting and ignoring, or adopting and amending to provide the flexibility needed to cost-effectively deliver energy efficient homes to the market during an economic downturn.

IBS Advisors works with builders, code officials, inspectors, and verifiers and the idea of trade-offs is attractive, particularly restoring trade-offs that had been in place from 1998-2009. But as an energy efficiency advocate, we need to ask if those trade-offs result in a home that is more energy efficient.

The Analysis

To answer that question, IBS Advisors conducted an analysis of specific proposed revisions that provide flexibility through trade-offs to achieve the annual energy budget set by the Standard Reference Design. The analysis employed a software tool accredited to perform calculations that demonstrate compliance with the IECC performance path. The procedures for verifying the software tool were produced by the National Renewable Energy Laboratory (NREL) and the Florida Solar Energy Center (FSEC) with support from the US Department of Energy. REM/Rate™ (v14.3) was used to conduct the analysis.

The methodology is similar to that used by Philip Fairey, Florida Solar Energy Center, in his report “Analysis of HERS Index Scores for Recent Versions of the International Energy Conservation Code (IECC)4” published January 11, 2013 and revised February 21, 2013.

Single story, 2000 ft2, 3 bedroom, wood frame homes were configured to simulate the 2012 IECC Standard Reference Design in 19 cities across the eight IECC climate zones. Following Philip Fairey’s methodology, the window areas of the proposed homes were configured to allow an analysis of one of the proposed revisions regarding window areas. This particular configuration allows a best and worst case orientation.


7

4Philip Fairey, “Analysis of HERS Index Scores for Recent Versions of the International Energy Conservation Code (IECC)” (Florida Solar Energy Center, February 2013), http://www.resnet.us/uploads/documents/FSEC-CR-1941-13_R01.pdf, retrieved September 9, 2013

http://www.resnet.us/uploads/documents/FSEC-CR-1941-13_R01.pdf




This methodology also included an attached garage. The foundations of the proposed homes had slab-on-grade in Climate Zones 1-2, vented crawlspaces in Climate Zones 3-4, and unconditioned basements in Climate Zones 5-8. The utility pricing was generated by state-based pricing taken from the Energy Information Administration website for both electricity and natural gas.5

This analysis produced more than 100 energy models to independently analyze five specific proposed revisions to the IECC. Those five are: RE72-13, RE109-13, RE116-13, RE166-13, and RE170-13.

In each model, the computer simulation used the specifications for the Standard Reference Design and values from the prescriptive Table R402.1.3 of the 2012 IECC. The only thing that changed in each iteration was the component under analysis.

The Results

Proposal RE72-13 revises Sections R402.4, R402.4.1.1, and R402.4.1.2, with corresponding International Residential Code (IRC) sections, and creates a new section R402.4.1.3, all changing the air infiltration limits from mandatory to prescriptive, while requiring installation performance and testing requirements to be mandatory. The prescriptive leakage rate proposed is 5 ACH50 (Air Changes per Hour at a 50 pascal pressure difference, 0.20 inches w.g.) in Climate Zones 1 and 2, and 3 ACH50 in Climate Zones 3-8, and the ventilation requirements remain as written in the current code. The tested home must still meet the annual energy budget produced by the prescriptive Standard Reference Design, but the builder has the flexibility to comply using currently accepted trade-offs such as improvements to the building thermal envelope.

The results of the analysis in the following table show this proposed change will result in a home that is just as or more efficient than a home built to the minimum prescriptive requirements. The home was modeled with 1 ACH over the prescriptive limit (Climate Zones 1-2, 6 ACH; Climate Zones 3-8, 4 ACH). In an analysis of 1,465 tested homes, the average infiltration rate was 3.68 ACH so there is high confidence these simulated values are appropriate.


8

5 http://www.eia.gov/electricity/monthly/epm_table_grapher.cfm?t=epmt_5_6_a ; http://www.eia.gov/dnav/ng/ng_pri_sum_dcu_nus_m.htm

http://www.eia.gov/electricity/monthly/epm_table_grapher.cfm?t=epmt_5_6_a

http://www.eia.gov/electricity/monthly/epm_table_grapher.cfm?t=epmt_5_6_a

http://www.eia.gov/dnav/ng/ng_pri_sum_dcu_nus_m.htm




CITY CLIMATE ZONE RE72-13 % COST IMPROVEMENT IN HEATING, COOLING, SERVICE WATER HEATING

COMPARED TO 2012 IECC

Miami 1A 5%

Orlando 2A 0%

San Antonio 2A 0%

Phoenix 2B 0%

Charlotte 3A 0%

Dallas 3A 0%

Oklahoma City 3A 0%

Las Vegas 3B 0%

Baltimore 4A 0%

Kansas City 4A 0%

Richmond 4A 0%

Philadelphia 4A 0%

Chicago 5A 0%

Pittsburgh 5A 0%

Denver 5B 0%

Minneapolis 6A 0%

Billings 6B 0%

Fargo 7A 0%

Fairbanks 8 0%

Proposal RE109-13 keeps mandatory duct leakage testing (except for duct systems and air handlers located entirely within the building thermal envelope) by revising Sections R403.2 and R403.2.2 (and corresponding IRC sections). This proposal restores flexibility by making the duct leakage limit of 4 cfm per 100 square feet of conditioned floor area prescriptive rather than mandatory. The home will still have to meet the annual energy use budget established by the prescriptive Standard Reference Design.


9

The analysis as shown in the following table indicates this proposed change will result in a home with equal or better energy efficiency than a home built to the minimum prescriptive requirements. The homes were modeled with 5 cfm per 100 square feet of conditioned space total as duct leakage, 1 cfm over the prescriptive limit. In an analysis of 1,633 duct system leakage tests, the average duct leakage rate was 5% of the conditioned floor area.



Miami 1A 4%

Orlando 2A 0%

San Antonio 2A 0%

Phoenix 2B 0%

Charlotte 3A 0%

Dallas 3A 0%

Oklahoma City 3A 0%

Las Vegas 3B 0%

Baltimore 4A 0%

Kansas City 4A 0%

Richmond 4A 0%

Philadelphia 4A 0%

Chicago 5A 0%

Pittsburgh 5A 0%

Denver 5B 0%

Minneapolis 6A 0%

Billings 6B 0%

Fargo 7A 0%

Fairbanks 8 0%


10

Proposal RE116-13 revises Sections R404.3.2.2 and Table R405.2(1) (and the corresponding IRC Section and Table) to permit either leakage to the outside or total leakage to be measured during the post-construction duct leakage test, while maintaining the 4 cfm per 100 square feet of conditioned floor area limit. It also provides a mechanism to allow credit for duct systems that are tested and are tighter than the prescriptive Standard Reference Design.

If duct leakage to the outside is not allowed, the computer-simulation model must assume leakage to the outside is the same as total duct leakage. Since those values are calculated differently, the resulting impact on energy use produced by those calculations is also different. Duct leakage to outside carries a direct energy penalty, and is the only duct leakage measurement that can be modeled with an impact on the energy use of the home.

The following table indicates that the analysis shows that this proposed change will not decrease the energy efficiency of the proposed home and will provide the contractor with flexibility to meet the required annual energy use budget. These homes were modeled with 4 cfm per 100 square feet of conditioned floor area as duct leakage to the outside and compared them to the 2012 IECC requirement of maximum total duct leakage of 4 cfm per 100 square feet of conditioned space.



Miami 1A 6%

Orlando 2A 1%

San Antonio 2A 1%

Phoenix 2B 0%

Charlotte 3A 0%

Dallas 3A 0%

Oklahoma City 3A 0%

Las Vegas 3B 0%

Baltimore 4A 0%


11



Kansas City 4A 0%

Richmond 4A 0%

Philadelphia 4A 0%

Chicago 5A 0%

Pittsburgh 5A 0%

Denver 5B 1%

Minneapolis 6A 0%

Billings 6B 0%

Fargo 7A 0%

Fairbanks 8 0%

Proposal RE166-13 restores the flexibility found in the 1998-2006 IECC, allowing contractors to use cost-effective and innovative advances in HVAC and service water heating equipment efficiencies to meet or be lower than the annual energy use budget produced by the prescriptive Standard Reference Design. It does this by using the same fuel type for heating, cooling, and water heating as the proposed home, and specifying the prevailing federal minimum efficiency standards for each type of equipment in the Standard Reference Design.

The current method neutralizes the gains found in technological innovations in mechanical equipment by specifying the same fuel type and level of efficiency in the Standard Reference Design as is used in the Proposed Home. This does not provide any incentive for contractors to install high performance equipment and, if a federal tax credit for building energy efficient homes references these codes (2009 and 2012), it will result in a significant economic loss to builders because they will not be able to achieve a 50% savings in heating and cooling required by the tax credit.

The analysis indicates that restoring flexibility by adopting this proposed change will result in homes that exceed the energy efficiency of homes built to the prescriptive Standard Reference Design. The models used the same component U-factors as the IBS Advisors, LLC! Do Trade-Offs Improve Energy Efficiency?

12

Standard Reference Design and only varied in the mechanical equipment as shown in the table below. The models also optimized the location of the systems when possible; in Climate Zones 3 & 4 they were installed in the vented crawlspace, and in Climate Zones 5-8 they were installed in the unconditioned basement.

CLIMATE ZONES HEATING COOLING SERVICE WATER HEATING

EQUIPMENT LOCATION

1 & 2 Baseline 8.2 HSPF Air Source Heat Pump

14 SEER Air Source Heat Pump

0.945 EF, 50 gallon electric storage water

heater

Vented Attic, DWH in garage

1 & 2 Efficient 8.6 HSPF Air Source Heat Pump

16 SEER Air Source Heat Pump

0.95 EF, 50 gallon electric storage water

heater


3 & 4 Baseline 80 AFUE gas furnace 14 SEER Air Conditioner

0.60 EF, 50 gallon gas storage water heater


3 & 4 Efficient 92 AFUE gas furnace 16 SEER Air Conditioner


Vented Crawlspace, DWH in garage

5 Baseline 80 AFUE gas furnace 14 SEER Air Conditioner



5 92 AFUE gas furnace 14 SEER Air Conditioner


Unconditioned Basement

6-8 Baseline 80 AFUE gas furnace 13 SEER Air Conditioner



6-8 92 AFUE gas furnace 13 SEER Air Conditioner


Unconditioned Basement

These efficiencies were selected based on what will be the federal prevailing minimum efficiencies for each type of equipment with an effective date in 2015.6


13

6 http://www.gpo.gov/fdsys/pkg/CFR-2012-title10-vol3/pdf/CFR-2012-title10-vol3-sec430-32.pdf, retrieved September 11, 2013; http://www1.eere.energy.gov/buildings/appliance_standards/product.aspx/productid/72, retrieved September 11, 2013

http://www.gpo.gov/fdsys/pkg/CFR-2012-title10-vol3/pdf/CFR-2012-title10-vol3-sec430-32.pdf

http://www.gpo.gov/fdsys/pkg/CFR-2012-title10-vol3/pdf/CFR-2012-title10-vol3-sec430-32.pdf

http://www1.eere.energy.gov/buildings/appliance_standards/product.aspx/productid/72

http://www1.eere.energy.gov/buildings/appliance_standards/product.aspx/productid/72

This analysis shown in the following table clearly indicates that energy efficient mechanical systems will create a cost-savings to the consumer and produce significant gains in energy efficiency that will carry us past the point of diminishing returns of building thermal envelope improvements.


14

Proposal RE170-13 revises Table R405.5.2(1) and the corresponding IRC Table, fixing the window area of the prescriptive based Standard Reference Design at 15% of the conditioned floor area. Using a fixed window area for the specifications of the Standard Reference Design based on the conditioned floor area of the Proposed Home allows homes with a lower window-floor area ratio (WFA) to receive credit for good design and provides a penalty for homes that use more than 15% WFA. In this proposal, the Standard Reference Design specified glazing is equally distributed in the four cardinal directions of North, South, East, and West and have prescriptive, climate-zone based U-factors and Solar Heat Gain Coefficients specified in the Standard Reference Design.

The window to floor area ratio in 3,000 homes built in Alabama, Louisiana, North Carolina, New Mexico, Tennessee, and Texas was analyzed. The average WFA ratio was 12.5%. The computer simulations had the glazing distributed unevenly in order to model best and worst orientation. A WFA of 12.5% was used with 35% of the glazing oriented North, 15% oriented East, 35% oriented South, and 15% oriented West. This provided a best case orientation of North and a worst case orientation of East. Additionally, the computer simulations had the same interior shade fraction as the Standard Reference Design and had no overhangs in order to provide a strict comparison based on orientation and glazing distribution. The window performance was based on the specifications for the Standard Reference Design in Table R402.1.3 of the 2012 IECC. The impacts on cost improvements are shown in the following table:

CITY CLIMATE ZONE RE170-13, BEST ORIENTATION, 12.5% WFA

% COST IMPROVEMENT IN HEATING, COOLING, SERVICE

WATER HEATINGCOMPARED TO 2012 IECC

RE170-13, WORST ORIENTATION, 12.5% WFA



Miami 1A 9% 8%

Orlando 2A 4% 3%

San Antonio 2A 3% 1%

Phoenix 2B 4% 2%

Charlotte 3A 3% 2%

Dallas 3A 4% 3%

Oklahoma City 3A 1% 0%


15

CITY CLIMATE ZONE RE170-13, BEST ORIENTATION, 12.5% WFA



RE170-13, WORST ORIENTATION, 12.5% WFA



Las Vegas 3B 3% 1%

Baltimore 4A 4% 3%

Kansas City 4A 3% 2%

Richmond 4A 2% 1%

Philadelphia 4A 4% 3%

Chicago 5A 3% 2%

Pittsburgh 5A 1% 0%

Denver 5B 5% 3%

Minneapolis 6A 1% 0%

Billings 6B 2% 1%

Fargo 7A -1% -2%

Fairbanks 8 0% -1%

The analysis shows a benefit provided for energy efficient design in all but two climate zones when compared to a fixed glazing area in the Standard Reference Design that represents 15% of the conditioned floor area of the Proposed Home.

Conclusion

Based on the analysis, approval of proposals RE72-13, RE109-13, 116-13, 166-13, and 170-13 will result in homes that are equally or more energy efficient than homes built to the prescriptive Standard Reference Design of the 2012 IECC. The homes under these proposed revisions will still have to meet or be lower than the annual energy use budget established by the prescriptive-based Standard Reference Design, ensuring both energy efficiency and flexibility to use innovative approaches and techniques to achieve that efficiency.


16

About the author:

Brett Dillon is the Managing Director of IBS Advisors, LLC, a consulting firm located near San Antonio, Texas. He was one of two subject matter experts hired by the US Green Building Council to develop their LEED for Homes Green Rater™ curriculum, and is a LEED Faculty™ member. He is also the Chair of the RESNET ANSI Standards Development Committee and serves on the RESNET Board of Directors. A former 4th generation builder, Brett combines his passion for sustainability and affordable housing into the work of his firm. A RESNET-credentialed HERS Rater Trainer and Quality Assurance Designee, he works with HERS Raters, builders, utility companies and local governments to instill sustainable practices into the built environment.


17


18

do trade-offs improve energy efficiency

Documents

iecc performance

conservation of energy

iecc standard reference

intended energy efficiency

annual energy use limit

annual energy use budget

performance path

proposed home