Building Efficiency What is desirable/possible? How do we achieve it?

Ceiling/Roof Combination of air sealing and insulation thickness Huge range in conventional buildings

Infiltration/Ventilation Build tight, ventilate right Buildings have ~ factor of 10 variation in their air exchange rates Reduce ventilation to what is needed for occupants Use HRV or economizer Do energy efficient fans reduce ventilation load?

Implicit space heating Internal gains More lighting means less heating But what about cooling?

What about cooling? Can we heat efficiently without compromising cooling? Overhangs Spectral selective glazings Dehumidification Radiant barriers Issue is peak, not absolute amount of cooling

Water heating Central problem is first cost Natural gas water heater (~$500) Electric water heater (~$100) Gas is faster and cheaper Safety issues? Does insulating the tank make a difference?

Lighting TypeEfficacy (lumens/W) CRILifetime (1000 hours) Incandescent Fluorescent Mercury HPS SOX180~ Metal Halide~100<

Other technologies Daylighting LEDs/OLEDs Microwave lights Challenge is balancing maintenance, safety comfort, capital cost, first cost, efficiency

Misc. = 87 TWh in 1995 (residential)

Do appliances consume energy when they are off? Which appliances? How much?

Summary Energy efficiency in buildings needs to address Efficiency of equipment Efficiency of building (envelope) But behavior plays a large role Take back effect Energy conservation or load shifting? Worker productivity/health costs dwarf savings by technology improvements Over-optimistic predictions

So what? Efficiency is a good thing Not without consequences Need to think about comfort, health, productivity How do we achieve it Laws (energy codes) Voluntary regulation What are the barriers to building efficient buildings? (Amory Lovin’s article on web page – please read first 20 pages) LEED critique also on web page

Regulating efficiency Appliance standards htmhttp:// htm Energy codes General idea is that society benefits Lower air pollution Less distribution issues

Voluntary Regulation People want to do the right thing Enhance corporate image Save operating costs Not as clearly demonstrated More productive employees Lower health care costs

Energy Codes

Austin energy code Conventional Energy Code Compliance Checklist Glazing percent of gross wall area:15%18%20%25% Exterior wallsR-13 Floors over unconditioned spaceR-11 R-13 Attics and knee wallsR-26R-30 Glazing U-factor (max) Low-e glass with Solar Heat Gain Coefficient (SHGC) of 0.40 or less must be installed on the windows; 2.Primary water heater and furnace equipment must not be an electric-resistant heating system and meet NAECA standards; 3.Duct connections must be properly sealed with mastic or approved UL-181A/B tape; and 4.Caulking and weather-stripping must be properly installed

Regulated efficiency Builders typically don’t like additional codes Save dramatic amounts of energy Improve quality of buildings Very cost effective Why aren’t building codes more widespread?

Voluntary Regulation People want to do the right thing Enhance corporate image Save operating costs Not as clearly demonstrated More productive employees Lower health care costs

Example – LEED v2.1 The LEED (Leadership in Energy and Environmental Design) Green Building Rating System™ is a voluntary, consensus-based national standard for developing high- performance, sustainable buildings.Green Building Rating System™

LEED™ V.2 Begins to define “green building” Tool to introduce, promote and guide an integrated building design process LEED will standardize green design in U.S. and institutionalize integrated design practices A compendium of green design elements Designed to capture environmental, economic, and human health benefits Created for and based on the US commercial market Self-assessing system for green buildings

LEED™ V.2 LEED Categories Sustainable Sites Water Efficiency Energy & Atmosphere Materials & Resources Indoor Environmental Quality Bonus Points Certification Levels LEED Certified pts. Silver pts. Gold pts. Platinum 52+ pts. Innovation Credits4 pts. Accredited Professional1 pt. TOTAL POINTS69 pts.

Examples of LEED™ credits Energy Efficiency (pg. 33 in PDF) CFC reduction (pg. 32 in PDF) Do you think a system like LEED™ is a good idea? What problems/issues do you foresee?

Challenges Multiple incentives in construction Greenwashing Substantial fraction of building impact comes from operation

Who conducts the orchestra?

Greenwashing A building that is less sustainable than it appears to be. “Green” sells

Green design REI Flagship Store (Seattle, WA) Many green design awards Energy efficient operation Sustainable material use

Greenwashing Does not meet state energy codes % above lighting code Mechanical code violations Significant design errors Conventional materials for major construction components Overbuilt

Further questions How does LEED prevent greenwashing? Can greenwashing be prevented? Do voluntary rating systems work?

Operation LEED doesn’t address operation and maintenance issues: Scarcity of measured data Commissioning Pilot standards currently being developed

Predictions Energy and water use projections are often significantly biased We overpredict savings/peak reduction LEED™ does not verify energy savings Take back effect Law of unintended consequences

Additional LEED Concerns Value engineering of LEED points Trading off between quantities that can’t be compared Who is at the table?