Getting the Thermal Envelope Right for All the Green Reasons

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Getting the Thermal Envelope Right for All the
Green Reasons
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About The Dow Chemical Company

• Founded in Midland, Michigan in 1897
• Supplies more than 3,300 products to customers in
  over 175 countries
• Annual sales of 67 billion
• 46,000 employees worldwide
• 34 on Fortune 500 list

Herbert Henry Dow
3
Dows Commitment to The Future

• Reduce our global energy intensity by 25 from
  2005-2015
• By 2025, we aim to have renewable energy provide
  10 of Dows global electrical energy demand
• By 2050, at least 50 of the energy consumed by
  Dow globally will be non-carbon-emitting
• LEARN more at www.dow.com/commitments/goals/energy
  .htm

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Getting the Thermal Envelope Right for All the
Green Reasons

• Setting the Stage
• Green Energy Efficiency
• Essential Element of Energy Efficiency Thermal
  Envelope
• Air infiltration
• Foundations
• Walls
• Roofs
• Putting it all together
• Questions

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WHAT IS GREEN?
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Green Energy Efficiency
Survey of top builders ranking The Importance of
Green Building Benefits in the Builder
Purchasing Decision
Lower Energy Bills
84
66
Make Home a Safer Place
Improve Indoor Air Quality
65
Improve the Environment
57
Reduce Water Usage
51
Reduce Dependence on Foreign Oil
49
Reduce Greenhouse Gases
38
Source NAHBRC Report Implications of the Soft
Housing Market for Suppliers of Building
Products 2007
7
Green Energy Efficiency
Survey of top builders ranking Trends Becoming
More Important to Builders
Energy Efficiency
70
61
Low Maintenance Homes
Design for Aging in Place
58
Green Building
51
Zero Energy Homes
31
Panelized Construction
30
Modular Construction
24
Source NAHBRC Report Implications of the Soft
Housing Market for Suppliers of Building
Products 2007
8
Green Energy Efficiency
Pro-Remodelers What is Green?
Energy Efficiency Benefit
88
Renewable Resource
72
Recycled Content
71
Reduced Indoor Off-gassing
55
45
High Degree of Durability
Manufacturers Environmental Policies
32
Locally Produced
30
Number of LEED Points Delivered
26
6
Other
Source Professional Remodeler Survey Reed
Business Information
9
Green Energy Efficiency
What should home buyers look for first in a green
home? Energy efficiency is the place to start.
www.energystar.gov
..energy efficiency is weighted heavily in a
green building program.
NAHB Research Center
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US Energy Consumption
Industry 25
Buildings48
Transportation 27
Energy Consumption GHG Emissions Build
Operate
Source Architecture 2030
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Dows Commitment to Greenhouse Gas Reduction
Kyoto
Indexed absolute Kyoto emissions
Between 1995-2005 Dow reduced its energy
intensity by 22. By 2015 Dow has committed to
reduce by an additional 25.
If the U.S. reduced its energy intensity by 25
by 2015, it could eliminate the oil equivalent of
all their current imports from the Persian Gulf.
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Reducing CO2 Emission Cost Effective Options

• This assessment by Swedish utility Vattenfall
  shows clearly that some ways to cutting carbon
  emissions are easier and more cost effective than
  others.

Global cost curve for green house gas abatement
measures beyond business as usual, green house
gases measured in GtCO2e1
Approximate abatement requiredbeyond business
as usual, 2030
Biodiesel
Industrial CCS
Waste
Carbon capture and storage (CCS) new coal
Coal-to-gas shift
Medium coal forestation
CCS coal retrofit
Cofiring biomass
Higher-costabatement
Industrialmotor systems
100 50 0 -50 -100 -150
Industrial feedstock substitution
Avoideddeforestation
CCS, enhanced oil recovery, new coal
Low-cost forestation
Livestock
Further potential3
Industrial non-CO2
18
26
33
Cost of abatement, per tCO2e2
Standby losses
550 ppm4
450 ppm4
400 ppm4
Sugarcane biofuel
Water heating
Air-conditioning
5 10 15 20 25 30 35
Abatement beyond business as usual, GtCO2e1 per
year in 2030
Building insulation is the most cost-effective
way of cutting carbon emissions.
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Reducing CO2 Emission Cost Effective Options
U.S. MID-RANGE ABATEMENT CURVE 2030
Residentialbuildings HVACequipment efficiency
CostReal 2005 dollars per ton CO2e
Commercialbuildings HVACequipmentefficiency
Afforestatoionof cropland
Coal power plants CCS rebuilds with EOR
Industrialprocessimprove-ments
Residentialbuildings Shellretrofits
Coal mining Methanemgmt
Fuel economypackages Light trucks
Solar CSP
Active forestmanagement
Distributedsolar PV
Residentialelectronics
Commercialbuildings Combinedheat andpower
Residentialwaterheaters
Commercialbuildings Controlsystems
Nuclearnew-build
Residentialbuildings Lighting
Abatementcost lt50/ton

PotentialGigatons/year
Onshore wind Low penetration
Industry Combinedheat andpower
Industry CCS newbuilds oncarbon-intensivepro
cesses
Onshore wind High penetration
Biomass power Cofiring
Cellulosicbiofuels
Carhybridization
Existing powerplantconversionefficiencyimprove
ments
Manufacturing HFCs mgmt
Coal power plants CCSnew builds with EOR
Residentialbuildings New shellimprovements
Onshore wind Medium penetration
Coal-to-gasshift dispatch ofexisting plants
Commercialelectronics
Natural gasand petroleumsystemsmanagement
Conservationtillage
Wintercover crops
Commercialbuildings CFL lighting
Commercialbuildings LED lighting
Coal power plants CCS rebuilds
Reforestation
Commercialbuildings New shellimprovements
Coal power plants CCS new builds
Fuel economypackages Cars
Afforestation ofpastureland
Source A proposal for GHG Abatement by 2030
McKinsey Company Report
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US Energy Intensity Trends

• Source DOE http//intensityindicators.pnl.gov/tot
  al_highlights.stm

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US Residential Energy Use 1985-2004

• Source DOE http//intensityindicators.pnl.gov/tot
  al_residential.stm

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Conclusions

• Green Energy Efficiency
• Buildings account for almost half of US energy
  consumption
• Building insulation is one of the most
  cost-effective ways to reduce CO2 emissions

Action

• Improve the performance of the thermal envelope

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The Thermal Envelope

• The barrier between indoor and outdoor
  environments
• Heat, Air, and Moisture (HAM)

Source Building Science Corporation
18
The Thermal Envelope

• Foundations
• Basement Walls (insulation interior or exterior)
• Crawl Space (closed)
• Above grade walls
• Roofs

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Heat Loss in Houses

• Approximate Heat Loss From a House
• 38 Air Infiltration
• 22 Basement Walls
• 17 Doors and Windows
• 17 Frame Walls
• 5 Ceilings
• 1 Basement Floor

Source REM/Design calculations
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Air Infiltration

• Typical 2,500 sq. ft. home has ½ mile of cracks
  and gaps that allow air infiltration. (Air
  Barrier Association of America)
• Enough air escapes from a typical house every day
  to fill two Goodyear blimps. Sealing air leaks is
  the first step in a program to improve the energy
  efficiency of your home. (www.urbanoptions.org)

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Air Infiltration

• Benefits of Reducing
• Air Infiltration
• Save Energy and Money
• Reduce Moisture Damage
• Improve Comfort

Source DOE http//www1.eere.energy.gov/consumer/t
ips/air_leaks.html
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The Whole House PictureHow the Savings Add Up
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Air Sealing
24
Air Sealing
25
Reduce Air Leakage
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Air Infiltration

• Conclusion
• Air infiltration is the largest source of heat
  loss in most houses
• In addition to energy savings, air sealing
  improves moisture control and comfort
• Action
• Use Energy Star Thermal Bypass Checklist, NAHB
  Green Building Guidelines, etc., to identify and
  seal air leakage pathways

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Poorly Insulated Basement Walls A Significant
Source of Heat Loss

• 22 of the heat loss in a leaky house comes from
  uninsulated basement walls
• More than 40 of the heat loss in a tight house
  comes from uninsulated basement walls

REM/Design calculations
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Concrete Walls Poor Thermal Performance
8-Inch Concrete

R1


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Building Science Principles

• Moisture in the air condenses into liquid at the
  dew point temperature
• Moisture damage can occur in the presence of high
  relative humidity as well as liquid water
• Heat flows from hot to cold

• Basement wall below grade can be cooler than 53º
  year round condensation
• Basement wall above grade can be much colder than
  53º for a few months per year condensation
• Insulate the basement wall so that surfaces
  exposed to indoor air are kept above the dew
  point temperature

65º Temp 65 RH 53º Dew-point temp
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Insulating Basement Walls

• Most basements are considered conditioned space,
  which means the basement walls should be
  insulated (not ceiling)
• Insulate on the exterior of the basement wall
• Insulate on the interior of the basement wall

Building Science Corporation
31
Exterior Basement Insulation

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Exterior Basement Insulation

• Full height insulation on the exterior of the
  basement wall
• Keeps interior of basement wall warm which
  reduces potential for condensation
• Protects the waterproofing membrane
• Some products also assist water drainage
• Insulation exposed above grade must be protected
  from damage

Source Building Science Corporation
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Insulate Foundation Wall Above Grade
When insulation is cut off at grade, more than
30 of the heat loss through the basement wall
can occur through the top 12 that is not
insulated
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Brush-On and Trowel-On Coatings Provide Durable,
Attractive Protection for Insulation Exposed
Above Grade
10 year old brush-on coating over insulation
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Interior Basement Insulation

• Insulate the basement wall so that surfaces
  exposed to indoor air are kept above the dew
  point temperature
• Most common methods of insulating interior of
  basement wall violate this principle moisture
  problems
• Studs batts or vinyl faced blankets can allow
  water vapor to reach the cold basement wall and
  condense

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Interior Basement Insulation

• A layer of foam plastic insulation against the
  interior of the basement wall keeps water vapor
  away from the cold basement wall
• The surface of the foam facing the basement is
  warm enough to reduce the potential for
  condensation

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Interior Basement Insulation
Some foam products can be left exposed to the
interior of the basement
38
Interior Basement Insulation
Drywall can be installed directly over the foam
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Rim Joist
Air Infiltration
Condensation
Air Infiltration
8 basement wall
Sill Seal
40
Interior Basement Insulation

• The same principles apply to rim joists air seal
  and insulate using a method that reduces heat
  loss AND reduces condensation
• Spray foam is a good choice

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Basement Systems
42
Crawl Spaces

• Build crawl spaces like a mini-basement

43
Vented vs. Closed Crawl Space
Closed R-10 rigid on wall
Vented R-19 batt under floor
Source Advanced Energy
Source Advanced Energy
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Problems with Vented Crawl Spaces
Source The Healthy Building Company
45
Problems with Vented Crawl Spaces
Source The Healthy Building Company
46
Problems with Vented Crawl Spaces
Source The Healthy Building Company
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Vents Do NOT Keep the Crawl Dry
Framing70-78º F
Ducts 55-65º F
H2O pipes 55-65º F
Floor 65-70º F
Source Advanced Energy
Source Advanced Energy
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Applied Building Science Principles
Crawl Space Research on Houses in North Carolina
49
Closed Crawl Space Energy Savings
50
Vented Crawlspace
RH
Dates
Advanced Energy
51
Sealed Crawlspace
RH
70
Dates
Advanced Energy
52
Closed Crawl Space System
Termite inspection strip
Spray foam insulation for rim joist
Sill Seal
Fire rated foam board
Continuous duty fan
6-mil polyethylene vapor sheet sealed at all
seams
Gravel / aggregate floor with drain
Poured concrete footer CMU block
53
Above Grade Walls
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CONVENTIONAL WALL

• FRAMING
• 2X4 16 OC
• CAVITY INSULATION
• R-13 BATTS
• SHEATHING
• OSB
• WATER RESISTIVE BARRIER Housewrap
• AIR BARRIER
• Housewrap

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Problems with Conventional Walls

• Thermal bridging through framing
• Excessive framing
• Inefficient cavity insulation
• Air infiltration through cracks and holes
• Condensation in wall cavity
• Rotting of wood sheathings and framing

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Start With the End in Mind
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If We Dont Obey the Wooden Rule, It Gets Ugly
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OSB Housewrap Not The Ideal Sheathing Solution

• Housewrap R-0
• Housewrap does not reduce thermal bridging
• Housewrap over OSB not best air barrier
• Wood still susceptible to moisture damage

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25 of a Typical Stud Wall is Not Insulated and
Studs Act as Thermal Bridges
25
of the Surface Area is Wood!
Winter
Interior
Exterior
Summer

• Heat flow increases with temperature differential
  (?T)

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Cavity Insulation is Limited
Is this wall insulated?
Window
The yellow areas show how little of the opaque
wall is covered by cavity insulation.
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CAVITY INSULATION CHOICES
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Signs of Thermal Bridging
Centex Homes-Apex, NC 2002
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Cavity Insulation is Limited
A layer of insulating sheathing covers the entire
opaque wall area, insulating wood framing and
areas not covered by the cavity insulation
Window
Insulated sheathings cover everything
Many foam sheathings can be installed as
water-resistive barriers
65
Advanced Framing

• Stacked framing
• Single top plate
• Two stud corner
• Insulated headers
• No header at non-bearing wall
• Drywall clips

Source Building Science Corporation
66
Advanced Framing Benefits

• Lower Cost
• Reduced Framing
• Framing factor reduced from 25 to less than 20
• Deeper cavity depth for higher insulation value

Source Building Science Corporation
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Advanced Framing Case Study

• Wood Frame Wall Summary
• 2x4 2x6 REDUCED
  16 oc 24 oc BY
• 8 Studs, pieces 1403 665 -52
• Bd Ft 5186 3082 -40
• COST 2749 1632 -40

Source Building Science Corporation
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High Performance Wall System

• 2X6 advanced framing vs. 2X4
• Critical air seal
• Optimum cavity insulation
• High R-value, air seal
• Continuous insulation sheathing
• SIPS, ICF

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Roofs, attics

• Consider making the attic part of the conditioned
  space
• Allows ducts in conditioned space to save energy
• Increased living area

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Cathedral Ceiling (vented)
Interior ceiling application (section view)
EXTERIOR
INTERIOR
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Cathedral Ceiling (unvented)
Interior ceiling application (section view)
EXTERIOR
INTERIOR
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Putting It All Together
50 Total Energy Reduction (1,500 ft2 house over
basement) Advanced Framing - less
1000 Insulating Sheathing - wash 95
Furnace - add 200 Simplified Ductwork -
less 500 Basement Insulation - add
1000 Cavity and Roof Insulation - add
250 Heat Exchanger - add 1000 Air Sealing
- add 250 16 SEER a/c - add
450 Tankless DHW - add 575 Compact
Fluorescent Lighting - add 250 Energy Star
Appliances - add 750 Approximately 3,500
more
Source Building Science Corporation
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Putting It All Together
50 Total Energy Reduction (1,500 ft2 house over
basement) Costs Approximately 3,500
more Financed For Approximately
25/month Saves 75/month in Utilities Cash
Flow is 50/month positive
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Benefits to the Builder by Going GREEN!

• Differentiation and marketability
• Less callbacks, enhanced reputation and quality
• Feature the essential elements of Green Building
• Save energy
• Improved indoor environmental quality
• Resource efficiency
• Water conservation
• Energy star
• Qualify for Federal Energy Efficient Tax Credit
  (2000)
• Maintain affordability

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Energy Efficiency
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Insulated Sheathing
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Thermal Bridging..Lets see it again!
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Extreme Air Infiltration Package
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Evaluating Insulations Effectiveness

• Must be in contact with an air barrier on all six
  sides
• Knee walls exposed to attics
• Band areas exposed to joist cavities
• Dropped ceilings
• Cantilevers
• Third Party Inspection-HERS rater

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Properly Size HVAC Equipment

• Perform and verify Manual J
• Downsize HVAC Equipment where appropriate
• Manual J Introduction - When equipment is
  oversized, efficiency is reduced, operating costs
  increase, and control over space conditions is
  lessened.

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Other Energy Efficient Highlights

• Low E, Argon Gas filled windows .32 U-Value
• 94 efficient natural gas furnace
• HERS rating on every home
• Blower door test on every home
• Duct blasting on every home

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Indoor Environmental Quality Safety, Lighting,
Comfort, Noise
Resource Efficiency Durability, Control
Moisture, Quantity of Materials
Water Conservation Toilets, Shower Heads,
Lavatories, Washing Machine
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Selling Green

• Home buyers appreciate added value in their homes
• People want to save money
• They want increased resale value
• Clients want increased comfort and a quieter
  environment
• People want their homes to be healthier and safer
  for their families
• People want to do their part to protect the
  environment and conserve natural resources for
  future generations
• BOTTOM LINE..
• The region is ready for GREEN, are YOU?

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