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Multi-Family Energy Measures
Webinar Series
November 10, 2010
Envelope Efficiency
2 October 2009
Sponsored by PG&E
“PG&E” refers to Pacific Gas and Electric Company, a subsidiary of PG&E Corporation. © 2010 Pacific Gas and Electric Company. All rights reserved.
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Program Description
Public service program:
Cash Incentives
Energy Design Assistance
Project Roundtable
Educational Opportunities
Program Coordination
Facilitate energy efficient design and construction in new multi-family
housing through cash incentives and design assistance
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Eligible Customers
Multi-family buildings in PG&E service territory:
3 or more attached units
New construction
Exceed 2008 Title 24 Standards by at least 15%
Complete construction and verification by December 31, 2015
Example building types: apartments, condos, townhomes, single-room occupancy, dormitories, assisted living*
* Please contact HMG if you are unsure of the eligibility of your project.
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Program Process
Participant provides HMG with:
– Completed application
– Title 24 documentation
– Architectural plan-set (+MEP)
– Service territory verification
– W9 Form
HMG conducts a plan review to verify energy measures, estimated savings, % better than Title 24
Project enrolled, receives ‘Letter of Enrollment’
Third party HERS verification conducted during construction to ensure energy measures installed*
HMG verifies any changes to project since enrollment and ensures as-built still exceeds Title 24 by at least 15%
Project completed and incentives paid
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*Note: the program verification protocols are in addition to any HERS measures on your Title 24
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Incentive Information
Developer Incentives: $100 per unit plus incremental incentives based on energy savings
HERS verification incentive: $60 per unit (max of $12,000 per project)
Energy Consultant Incentives:
$50 per unit (max of $10,000 per project)
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Envelope Efficiency
Section 1
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Envelope Efficiency
Multi-Family Buildings
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Flows in Buildings
Heat moves from hot to cold
Air moves from higher to lower pressure
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Some Fundamentals
Heat Transfer
– Heat transfer is always from the hot to cold.
Picture Source, Beodom.com
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Some Fundamentals
Heat Transfer Mechanisms - Conduction
Picture Source: mikecurtis.org
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Some Fundamentals
Heat Transfer Mechanisms – Conduction
– Good Conductors – Rapid transfer
– Poor Conductors – Slow transfer
Picture Source: mikecurtis.org
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Some Fundamentals
Heat Transfer Mechanisms - Convection
Picture Source: mikecurtis.org
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Some Fundamentals
Heat Transfer Mechanisms - Radiation
Picture source: mikecurtis.org
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Air Leakage
Exfiltration – leakage indoors to outdoors
Infiltration – leakage from outdoors to indoors
Conditions for air infiltration or exfiltration
– Pressure difference (high to low)
– Penetrations in building envelope (holes and cracks)
Driving forces
– Temperature differences (stack effect)
– Wind
– Mechanical systems
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Multi-family Buildings
Many potential sources for air infiltration and air leakage
Dropped ceilings, plumbing chases, porches, chimneys
Vertical shafts (elevators, stairs, pipes, wires, steel columns
Horizontal cavities (floors, ceilings, recessed lights)
Ventilation and Indoor Air Quality
Shafts linking kitchen and bathroom exhaust systems to outdoors
Corridor and lobby ventilation
Picture Source: Residential Energy. Krigger and Dorsi
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Reducing Heat Flow
Insulate to reduce conduction
Control air flow to reduce infiltration/convection
Provide shading/select windows to control heat absorbed
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Controlling Air Flow
Designed and Un-designed holes
– Vents and chimneys (designed)
– Access doors, furred walls, dropped ceilings, bottom plate to subfloor connections, wiring-plumbing penetrations, shafts, lighting, etc.
Block infiltration and convection pathways to attics and crawlspaces
Seal leaky joints in walls, floors and ceilings
Seal attic doors
Seal ductwork in unconditioned space
Balance pressures within house
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Controlling Air Flow
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Envelope Efficiency
The Building Envelope or Building Enclosure
– Separates the outdoor environment from the indoor environment
Thermal Boundary
Home Energy Partners
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Envelope Efficiency
Create the thermal boundary
– Thermal boundary around a building is the line that slows down and/or stops heat from moving between unconditioned to conditioned spaces
Install insulation correctly
– No compressions, voids or gaps
– Rim joists between floors insulated
– Maintain contact between air barrier and insulation
Insulate and seal
– Knee walls, behind bath tubs, skylight wells, soffits
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Insulation
Fibrous insulation – Blankets
– Batts
– Loose-fill
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Insulation
o Fills irregular spaces
o Flush with air barrier
o No cutting and splitting
o But, must allow to dry
Source: Doug Beaman, Douglas Beaman Associates
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Insulation
Blown-in-Blanket
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Insulation Spray foam
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Insulation
Rigid foam panels – Insulating concrete forms
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Insulation
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Insulation
High Rise ICF Building – 15 Stories – Ontario, Canada
– See article by Joseph W. Lstiburek, High Rise Igloos
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Insulation
High Rise ICF Building – R-16 to R-25
– Each unit isolated from adjacent units
– Complex aesthetics possible
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Insulation
Rigid foam panels – Structural Insulated Panels
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Windows, Glass Doors
Glass windows and doors:
– Can account for 25% of heating load
– Can account for 50% of cooling load
Window Characteristics:
– Glass Assembly
– Sash
– Frame
– Rough Opening
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Windows, Glass Doors
Windows with lower U-factors minimize heat loss in heating dominated areas
Windows with lower solar heat gain coefficients minimize heat gain in cooling dominated areas
– SHGC = amount of solar energy allowed through the window
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Windows, Glass Doors
Whole window performance
Labels required for inspection
The only reliable way to:
– Determine window properties
– Compare products
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Windows, Glass Doors
Manufactured Products – Most common
– NFRC labeled (National Fenestration Rating Council)
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Windows, Glass Doors
Window technologies: – Double or triple paned glass
– Inert gas fill (e.g., krypton, argon, nitrogen)
– Low-emissivity (LowE) glass films or coatings
– Window tinting
– Insulated frames
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Windows, Glass Doors
Glass or Patio Doors
– Lose heat much faster
– LowE coatings available
– The frame is an important consideration Metal with thermal break
Insulated frames
Swinging doors have a tighter seal than sliding
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Windows, Glass Doors
High Rise Glass – Manufactured
– Site built
Use NFRC label or use the CEC Default tables for U-factors and SHGC numbers
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Site Built Fenestration
Component Modeling Approach (CMA)
New concept:
– Build based on predefined & certified components
– Simulate energy performance (rather than using default values)
For more information:
– www.h-m-g.com/CMAProgram.aspx
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Windows and Glass Doors
Select based on NFRC* performance values
Design appropriate shading devices
If you can’t shade, then minimize SHGC**
Minimize U-factors, e.g. dual pane glazing
Better windows can help reduce heating and cooling equipment size – saving first costs
In mild, coastal areas glazing with very low SHGC values can increase heating energy usage
* NFRC = National Fenestration Ratings Council ** SHGC = Solar Heat Gain Coefficient
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Building Envelope – Framing
Advanced Framing Techniques: Optimum Value Engineering (OVE)
– Minimizes materials used
– Resulting in improved energy performance
– Lower labor costs
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Building Envelope – Framing
Image from “The American Cottage Builder” published in 1854
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Building Envelope – Framing
Advanced Framing Techniques: Optimum Value Engineering (OVE)
– Wall and floor framing at 24” on center
– Modular layout
– Single top plate Exterior, bearing and
interior walls
– Right sized headers
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Building Envelope – Roofs
Cool Roofs
– A cool roof reflects the sun’s heat back to the sky instead of transferring the heat to the building
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Building Envelope – Roofs
Cool Roof - Terms
– Reflectance: the ability of a material to bounce back solar radiation
– Emittance: the ability of heat to escape from a surface once it is absorbed
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Building Envelope – Roofs
Solar Reflectance Index – combination of reflectance, emittance and solar radiation (formula by Lawrence Berkeley National Laboratory)
– Standard white = 100
– Standard black = 0
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Building Envelope – Roofs
Cool Roof products
– Ref = Reflectance, Emi = Emittance, SRI = Solar Reflectance Index, A = Aged
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Building Envelope – Roofs
The Green Roof – Long life span
– Better air quality
– Great insulation
– A cooler environment
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Building Envelope – Roofs
The Green Roof
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In Summary
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Upcoming Trainings
Sources & Methods of Energy Efficient Multi-Family Financing
– Webinar: Wednesday, December 8, 2010
Energy Measures Series: Domestic Hot Water Measures & Concepts
– Webinar: Wednesday, January 12, 2011
CMFNH HERS Verification Overview
– Webinar: Tuesday, January 25, 2011
Register: multifamily.h-m-g.com/training/
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Title 24 Resources
2008 Building Energy Efficiency Standards: http://www.energy.ca.gov/title24/2008standards/
CEC Blueprint: http://www.energy.ca.gov/efficiency/blueprint/
– Sign up for newsletter here
Energy Efficiency Hotline:
– title24@energy.state.ca.us
– Phone: 916-654-5106 or 1-800-772-3300 (toll free in CA)
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Design Resources
DOE Building America Program
– www.buildingamerica.gov
EPA ENERGY STAR® Program
– www.energystar.gov
US Green Building Council
– www.usgbc.org
Energy Design Resources (Savings By Design)
– www.energydesignresources.com
American Society of Heating, Refrigeration and Air Conditioning Engineers
– www.ashrae.org
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Energy Efficiency Resources
California Association of Building Energy Consultants – www.cabec.org
Home Energy Magazine – www.homenergy.com
Title 24 Energy Standards – www.energy.ca.gov/title24/2008standards
Title 24 Energy Standards – www1.eere.energy.gov/buildings
Gas Appliance Manufacturers Association – www.gamanet.org
National Fenestration Rating Council
– www.nfrc.org
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Renewable Energy Resources
Solar Ratings & Certification Corporation – www.solar-rating.org (SRCC)
California Solar Energy Industries Association – www.calseia.org (CalSEIA)
Energy Efficiency & Renewable Energy Office – www.eere.energy.gov (EERE)
National Renewable Energy Laboratory – www.nrel.gov (NREL)
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Thank you!
Heschong Mahone Group
916.962.7001
Linda S. Murphy, CEA, CEPE
murphy@h-m-g.com
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