heat flow - certainteed · !introduction to heat flow Œ conduction: transfer of heat between...

Heat FlowHeat Flow

The Art of Building Science

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!Introduction to Heat Flow!Introduction to Heat Flow

!Heat always flows from a region ofhigh temperature to a region of lowertemperature

!Introduction to Heat Flow!Introduction to Heat Flow

� Conduction: Transfer of heatbetween materials of differenttemperatures while in direct contact

! Three modes of heat flow

!Introduction to Heat Flow!Introduction to Heat Flow

� Conduction: Transfer of heatbetween materials of differenttemperatures while in direct contact

� Convection: Transfer of heat dueto the motion of gas or liquid overa surface

! Three modes of heat flow

!Introduction to Heat Flow!Introduction to Heat Flow

� Conduction: Transfer of heatbetween materials of differenttemperatures while in direct contact

� Convection: Transfer of heat dueto the motion of gas or liquid overa surface

� Radiation: Transfer of heat fromone object to another due toelectromagnetic waves

! Three modes of heat flow

Benefits of ControllingHeat Flow in a HouseBenefits of ControllingHeat Flow in a House

!Occupant comfort

!Energy efficiency

Heat FlowScientific Principles

Heat FlowScientific Principles

Heat Transfer Problems & SolutionsHeat Transfer Problems & Solutions

!Roof/ceiling system

!Walls

!Windows

!Basements

!Crawlspaces & Slabs

Roof/Ceiling

Systems

Roof/Ceiling

Systems

Roof/Ceiling System ProblemsRoof/Ceiling System Problems

!Ceiling surfacecondensationand staining

Roof/Ceiling System ProblemsRoof/Ceiling System Problems

!Underside of roofdeck deterioration

Roof/Ceiling System SolutionsRoof/Ceiling System Solutions

!Cathedral ceilinginstallation

Roof/Ceiling System SolutionsRoof/Ceiling System Solutions

!Properly support& protect kneewall insulation

InsulationInsulationSheathingSheathing

Roof/Ceiling System SolutionsRoof/Ceiling System Solutions

!Properly insulaterecessed lighting

Infrared View

Roof/Ceiling System SolutionsRoof/Ceiling System Solutions

!Insulate attichatch

Roof/Ceiling System SolutionsRoof/Ceiling System Solutions

!Install atticbaffles tomaintaininsulationeffectiveness

Wood Stud

Walls

Wood Stud

Walls

Wood Stud Wall Insulation ProblemsWood Stud Wall Insulation Problems

!Uncomfortable occupant space

!Cold surfaces promote condensationand staining

Wood Stud Wall System SolutionsWood Stud Wall System Solutions

!Qualityinstallation

Wood Stud Wall System SolutionsWood Stud Wall System Solutions

!Avoid insulationvoids

Infrared View

insulation void

near top plate

VoidVoid

VoidVoid

Wood Stud Wall System SolutionsWood Stud Wall System Solutions

!Blow-In-BlanketSystem (BIBS)

Wood Stud Wall System SolutionsWood Stud Wall System Solutions

!Avoid insulationcompression

Compressed battCompressed batt

Wood Stud Wall System SolutionsWood Stud Wall System Solutions

!Properly insulatearound plumbingand electricalpenetrations

Poor fitPoor fit

CompressedCompressed

VoidVoid

Wood Stud Wall System SolutionsWood Stud Wall System Solutions

!Use insulatingsheathings toincrease overallR-value

WindowsWindows

Window ProblemsWindow Problems

!Uncomfortable interior space due toradiation heat flow

Window ProblemsWindow Problems

!Uncomfortable interior space due toradiation heat flow

!Condensation due to cold window surfaces

Window ProblemsWindow Problems

!Uncomfortable interior space due toradiation heat flow

!Condensation due to cold window surfaces

!Ultra-violet light exposure: Sunlightdegrades interior furnishings

Window System SolutionsWindow System Solutions

Install high performance windowsLook for the NFRC label

Window System SolutionsWindow System Solutions

! Frame type

! Glazing type

! Gas Fill

! Low-E coatings

Install high performance windowsLook for the NFRC label

Window System SolutionsWindow System Solutions

Energy Star recommended maximums

U-factor � Like R-value,indicates thermal performance

0.75Southern Zone

0.40Central Zone

0.35Northern Zone

U-factor

Lower is better

Window System SolutionsWindow System Solutions

Energy Star recommended maximums

Solar Heat Gain Coefficient �Indicates efficiency in preventingsolar radiation from heating house

0.40Southern Zone

0.55Central Zone

AnyNorthern Zone

SHGC

Lower is better

Window System SolutionsWindow System Solutions

Installation is Critical!

Even the best windowswill perform poorly

unless they areinstalled correctly.

BasementsBasements

Below Grade BasementInterior ProblemsBelow Grade BasementInterior Problems

!Occupant comfort

!Energy efficiency

Below Grade BasementInterior SolutionsBelow Grade BasementInterior Solutions

!Finished walls �Fill entire spacewith unfacedinsulation betweenfoundation wall andinterior sheathing

Below Grade BasementInterior SolutionsBelow Grade BasementInterior Solutions

!Unfinished walls �Use perforated firerated facing

Perforated FSK facing

Perforated PSK facing

Below Grade BasementInterior SolutionsBelow Grade BasementInterior Solutions

!Ceilings

� Conditioned space�Insulation improves sound control

� Semi-conditioned space�Insulation improves energy efficiency& comfort

Crawlspaces

and Slabs

Crawlspaces

and Slabs

Crawlspace ProblemsCrawlspace Problems

!Floor surface temperatures above crawlspace

!Energy efficiency above crawlspace

Crawlspace SolutionsCrawlspace Solutions

!Ventedcrawlspace �minimum R-19should be installedin the floor/ceilingcavity for coldclimates

Crawlspace SolutionsCrawlspace Solutions

!Unventedcrawlspace�floor/ceilingcavities or wallsshould be insulatedin warm-humidclimates

Slab SolutionsSlab Solutions

!Some climates may require slab edgeinsulation

� Check your building codes

Pay Attention

to Details

Pay Attention

to Details

Pay Attention to DetailsPay Attention to Details

!Align air andthermal barriersin dropped ceiling

Pay Attention to DetailsPay Attention to Details

!Properlyinsulatebathrooms tokeep tub andshower surfacescomfortable

VoidsVoids

Compression

Compression

Insulate here to finish job

Pay Attention to DetailsPay Attention to Details

!Insulate, sheathand air sealkneewalls overgarages

Pay Attention to DetailsPay Attention to Details

!Don�t miss insulatingaround ALLirregular details

� Bay windows

� Overhangs

� Dropped soffits

� Any irregular walls, etc.

Control

heat flow��for comfort

and energy

efficiency.

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