Overview of U.S. Building Energy Regulations
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The document provides an overview of U.S. building energy regulations and codes. It discusses the U.S. DOE building energy codes program and pathways for codes, including prescriptive and performance-based approaches. It also summarizes fenestration requirements in ASHRAE 90.1 and the 2012 IECC, including U-factor and SHGC limits. Challenges in developing codes and standards are outlined, and goals for the new ASHRAE 189.1 standard are presented. The need for integrated programs that consider the entire building lifecycle is discussed.
Overview of U.S. Building Energy Regulations
- 1. IEA Building Envelope Technologies and Policies Workshop, Paris, 17/11/2011 Overview of U.S. Building Energy Regulations Stephen Selkowitz Building Technologies Department Lawrence Berkeley National Laboratory Additional Content Provided by Marc LaFrance, USDOE John Hogan, City of Seattle Tom Culp, Birchpoint Consulting
- 2. Prior Windows Roadmap: U.S. DOE 1
- 3. Window Performance Goals to 2020 2
- 4. Envelope Impacts on Building Energy Consumption Buildings consume 40% of total U.S. energy • 71% of electricity and 54% of natural gas Envelope Does Not Directly Consume Energy • Allocating Impact on End Use Energy is a Challenge 42% 57%
- 5. Envelope – Building Energy Consumption Impacts 57% of Other Loads 12% Heating Computers 23% 2% Appliances 12% Electronics Cooling 7% 13% Water Heating 10% 1/7 US Economy Ventilation Lighting • 133 Billion $/yr 3% 18% • 13.9% US Energy • 3.5% Global Energy 4
- 6. DOE Building Energy Codes Program 5
- 7. Codes and Standards: Pathways • Prescriptive – fixed – Simplest, least costly compliance, most restrictive • Prescriptive – with tradeoffs – Simple to follow, More flexibility, more complexity • Performance Based – Design – Design an “equivalent” building that meets code; then show your building is equal or better – Very flexible, but costly in terms of design – Constraints in terms of operational issues – Requires accurate, useable energy simulation tools • Performance Based – Measured Outcomes – How to account for actual use, occupancy – What if performance does not meet goals? – More pressure on tools to accommodate “reality” 6
- 8. Design Simulation to Code vs Measured Performance LEED Energy Predictions vs Utility Bills A few facts: Measured=Design 1. Various building types, ages, locations 2. Average over all projects not bad Measured EUI 3. Max over-predict by 120% 4. Max under-predict by 65% (kBtu/ft2) 5. Almost all under-predicted for low energy designs (red triangle: EUI <= 40) 6. Uncalibrated simulated results Design EUI (kBtu/ft2) Source: Energy performance of LEED-NC buildings, NBI, 2008
- 9. The Regulatory Ecosystem • National, State, Local – ASHRAE 90 is primary national Code; 3yr update cycle – California: Title 20, 24 Building Codes, updated every 3 yrs • Targets- Net Zero Energy Use by 2025/2030 • Mandatory and Voluntary – US Green Building Council – LEED ratings- broader than energy – US EPA/DOE EnergyStar • Variants: New and Retrofit; Building Type • Continuous Updates and Revisions – time consuming, costly • Codes are “Data Hungry” – Where does it come from? Who certifies it? Can it be shared • Design Operations – Energy Use Disclosure- private, public – Audits every 5 years – Required to Meet Targets? • Education and Training – Architects/Engineers – Code officials – How to address new technologies, systems etc. 8 • Overloading the Building Owner?
- 10. Building Owners Need Integrated Programs for Maximum Market Impact with Lowest Cost and Effort • Owners swamped by yet another “program” approach to building energy improvements; numerous discrete (overlapping) programs: – Audit programs DR programs – Rebate programs Renewables programs – Benchmark programs LEED programs What Not – EPACT Tax Credit programs – Commissioning programs Retrofit programs Title 24: Codes and standards To Do – Load Management programs ( + Life safety, earthquake, disabled access, ….) For New Buildings: The “determine performance goals, use integrated design approach with state-of-the-art smart systems, construct and commission, operate to meet targets” Program For Existing Buildings: The “benchmark your energy use and set goals, actively monitor end use What’s Needed and indoor environmental quality, diagnose and fix problems as they arise - > take operational and/or investment actions to meet goals, and actively monitor feedback, re-evaluate benchmarks in light of costs…” Program “IT management” problem; Build these programs around a single shared “life-cycle” Building Information Model (BIM)
- 11. Framework for Codes • Base Energy Codes – 2012 IECC – ASHRAE 90.1 – California Title 24 • Green Codes – ASHRAE 189.1 – International Green Construction Code (IECC) • Voluntary – LEED 2012 – Energy Star 10
- 12. Goals for Standard 189.1 • Establish mandatory criteria in all topic areas: - one “problem” with existing rating systems is that they contain few mandatory provisions - consequently, a designer can achieve “points” & claim that they have a “green building”, but still make no improvements in some areas • Provide simple compliance options: - another critique of existing rating systems is the need for extensive calculations (e.g. energy) • Complement green building rating programs: - Std 189.1 is not intended to compete with green building rating programs
- 13. Challenges • Using normative (code) language • Determining the stringency for a “minimum” standard • Identifying standards or regulations to cite (could not reference guidelines) • Coordinating with other U.S. National initiatives U.S. Federal agencies Memo of Understanding, American Institute of Architects, National Conference of Mayors • Creating something that is enforceable by AHJs (authority having jurisdiction)
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- 16. Fenestration: What is required if using the prescriptive path? Note: these are very approximate Current ASHRAE 90.1-2007 ASHRAE 90.1-2010 2012 IECC 2009 IECC Zone 1 Zone 1 Single glazing? (but may need double (but may need double glazing No glazing to meet SHGC) to meet SHGC) Everywhere Everywhere Low-e glazing? (unless use dark tint or (unless use dark tint or Everywhere reflective in zones 1-3) reflective in zones 1-3) Thermally broken Zones 2-8 Zones 4-8 Zones 4-8 (Wide TB needed in frame? zones 4-8) Argon and/or warm Zones 7-8 Zones 7-8 Zones 4-8 edge spacer? Zones 7-8 Zones 6-8 for heavy products. Triple glazing? Not required Not required Maybe zones 4-8 for very heavy products if cannot use wider TB 15
- 17. International Energy Conservation Code (IECC) • 2012 IECC completed last fall. • 30% increase in stringency over 2006 IECC – New minimum skylight area requirements in large spaces – Low-e everywhere – Increased use of thermal break, argon, warm edge spacers – Triple glazing in the north – Removed allowance for monolithic hurricane impact- resistant products in zone 1 – Tighter air leakage requirements – Recognizes dynamic glazing – Includes on-site renewable energy (BIPV, rooftop PV)
- 18. 2012 IECC Prescriptive Requirements U U Zone SHGC vertical skylight 8,7,6,5, and 0.32 0.55 NR Marine 4 4 except 0.35 0.55 0.40 Marine 3 Marine 0.35 0.55 NR 3 except 0.35 0.55 0.25 Marine 2 0.40 0.65 0.25 1 NR 0.75 0.25 17
- 19. U-factor Changes from 2006 to 2012 Climate 2006 IECC 2009 IECC 2012 IECC Zone Vertical Skylight Vertical Skylight Vertical Skylight 1 1.20 0.75 1.20 0.75 NR 0.75 2 0.75 0.75 0.65 (0.75 for 0.75 0.40 0.65 hurricane products) (0.65 for 3 0.65 0.65 0.50 0.65 0.35 0.55 hurricane products) 4 except 0.40 0.60 0.35 0.60 0.35 0.55 Marine 5 and 0.35 0.60 0.35 0.60 0.32 0.55 Marine 4 6 0.35 0.60 0.35 0.60 0.32 0.55 7 and 8 0.35 0.60 0.35 0.60 0.32 0.55 Blue indicates change from previous version.
- 20. SHGC Changes from 2006 to 2012 Climate 2006 IECC 2009 IECC 2012 IECC Zone Vertical Skylight Vertical Skylight Vertical Skylight 1 0.40 0.40 0.30 0.30 0.25 0.30 2 0.40 0.40 0.30 0.30 0.25 0.30 3 0.40 0.40 0.30 0.30 0.25 0.30 4 except NR NR NR NR 0.40 0.40 Marine 5 and NR NR NR NR NR NR Marine 4 6 NR NR NR NR NR NR 7 and 8 NR NR NR NR NR NR Blue indicates change from previous version. Note that 2009 IRC has higher 0.35 SHGC, different than 2009 IECC
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