IEA Building Envelope Technologies and Policies Workshop, Paris, 17/11/2011

Stephen Selkowitz

Building Technologies Department

Lawrence Berkeley National Laboratory

Overview of U.S. Building Energy Regulations

Additional Content Provided by

Marc LaFrance, USDOE

John Hogan, City of Seattle

Tom Culp, Birchpoint Consulting

1

Prior Windows Roadmap: U.S. DOE

Window Performance Goals to 2020

2

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%

Envelope – Building Energy Consumption

4

Heating

23%

Cooling

13%

Lighting

18%

Ventilation

3%

Water Heating

10%

Electronics

7%

Appliances

12%

Computers

2%

Other

12%

Impacts 57% of Loads

• 133 Billion $/yr • 13.9% US Energy • 3.5% Global Energy

1/7 US Economy

DOE Building Energy Codes Program

5

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

Design Simulation to Code vs Measured Performance LEED Energy Predictions vs Utility Bills

A few facts: 1. Various building types, ages,

locations 2. Average over all projects not bad 3. Max over-predict by 120% 4. Max under-predict by 65% 5. Almost all under-predicted for low energy designs (red triangle: EUI <= 40) 6. Uncalibrated simulated results

Source: Energy performance of LEED-NC buildings, NBI, 2008

Design EUI (kBtu/ft2)

Mea

sure

d E

UI

(kB

tu/f

t2)

Measured=Design

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.

• Overloading the Building Owner? 8

What Not To Do

• Owners swamped by yet another “program” approach to building energy improvements; numerous discrete (overlapping) programs:

– Audit programs

– Rebate programs

– Benchmark programs

– Commissioning programs

– Retrofit programs

– Load Management programs

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 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)

What’s Needed

DR programs

Renewables programs

LEED programs

EPACT Tax Credit programs

Title 24: Codes and standards

( + Life safety, earthquake, disabled access, ….)

Building Owners Need Integrated Programs for Maximum Market Impact with Lowest Cost and Effort

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

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

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)

13

14

Fenestration: What is required if using the prescriptive path? Note: these are very approximate

Current ASHRAE 90.1-2007

2009 IECC ASHRAE 90.1-2010 2012 IECC

Single glazing? Zone 1

(but may need double glazing to meet SHGC)

Zone 1 (but may need double glazing

to meet SHGC) No

Low-e glazing? Everywhere

(unless use dark tint or reflective in zones 1-3)

Everywhere (unless use dark tint or reflective in zones 1-3)

Everywhere

Thermally broken frame?

Zones 4-8 Zones 4-8 Zones 2-8

(Wide TB needed in zones 4-8)

Argon and/or warm edge spacer?

Zones 7-8 Zones 7-8 Zones 4-8

Triple glazing? Not required Not required

Zones 7-8 Zones 6-8 for heavy

products. Maybe zones 4-8 for

very heavy products if cannot use wider TB 15

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)

2012 IECC Prescriptive Requirements

17

Zone U

vertical

U skylight

SHGC

8,7,6,5,

and

Marine 4

0.32 0.55 NR

4 except

Marine 0.35 0.55 0.40

3 Marine 0.35 0.55 NR

3 except

Marine 0.35 0.55 0.25

2 0.40 0.65 0.25

1 NR 0.75 0.25

U-factor Changes from 2006 to 2012

Climate

Zone

2006 IECC 2009 IECC 2012 IECC

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

hurricane

products)

0.75 0.40

0.65

3 0.65 0.65

0.50 (0.65 for

hurricane

products)

0.65

0.35 0.55

4 except

Marine

0.40 0.60 0.35 0.60 0.35 0.55

5 and

Marine

4

0.35 0.60 0.35 0.60 0.32 0.55

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.

SHGC Changes from 2006 to 2012

Climate

Zone

2006 IECC 2009 IECC 2012 IECC

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

Marine

NR NR NR NR 0.40 0.40

5 and

Marine 4

NR NR NR NR NR NR

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

20

21

22

23