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
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
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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”
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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.
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• 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
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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)
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
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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