Crash Course

1

• Crash Course
• in Building Science
• Why Homes Work And Fail

2
OUTLINE

• Why Building Science is Important
• Building Science Key Components
• Controlling Air Flow
• Controlling Thermal Flow
• Controlling Moisture Flow
• ENERGY STAR Solutions
• Action Plan

3
WHY IS BUILDING SCIENCE IMPORTANT?
4
WHY IS BUILDING SCIENCE IMPORTANT?
We all want a home that is

• Affordable
• Comfortable
• Healthy
• Durable

5
WHY IS BUILDING SCIENCE IMPORTANT?

• For your home to do its job,
• it must separate

The inside
from the outside.
6
WHY IS BUILDING SCIENCE IMPORTANT?

• Wind
• Rain
• Ground water
• Radon
• Uncomfortable temperatures
• Humidity
• Bugs and pests

If those problem areas arent addressed, youre
probably letting in
7
WHY IS BUILDING SCIENCE IMPORTANT?

• To understand how to most effectively keep these
  things out of our homes, lets take a look at
  some key components to high performance homes

8
BUILDING SCIENCE KEY COMPONENTS
9
FORCES ON YOUR HOME
Driving Forces
Pressure
Heat
Moisture
Courtesy of Southface Institute
Stack effect is a convective loop throughout the
entire house cause by differences in pressure.
10
FORCES ON YOUR HOME
Driving Forces always move in the same direction
to

• More
• Pressure
• Moisture
• Heat

• Less
• Pressure
• Moisture
• Heat

11
DRIVING FORCES

• Conditions needed for air leakage
• Holes
• Driving Forces (pressure) Across the Holes

Air will take path of least resistance through
largest hole.
12
FORCES ON YOUR HOME

• Keeping this simple rule in mind, there are three
  major driving forces that need to be controlled

13
BUILDING SCIENCE KEY COMPONENTS
Control Air Flow
Control Moisture Flow(Vapor, Bulk)
Control Thermal Flow
14
HIGH PERFORMANCE HOMES
Affordable Comfortable Healthy Durable
Why
Control Moisture Flow
Control Thermal Flow
Control Air Flow
How
Driving Forces
Stack Effect
Fans
Conduction
Convection
Radiation
Bulk
Vapor
In the sections the follow, well discuss these
components and how they can explain common
problems we see in homes.
What
15
CONTROLLING AIR FLOW
16
CONTROLLING AIR FLOW
Driving Forces
Pressure
Heat
Moisture
Courtesy of Southface Institute
Stack effect is a convective loop throughout the
entire house cause by differences in pressure.
17
HERE ARE THE LARGER HOLES
Access Panels
Chases
Dropped Ceilings
Ceiling fixtures
Window Openings
Sill Plates
Vents
Plumbing Penetrations
Door Openings
Ducts
18
CONTROLLING AIR FLOWCHIMNEY CHASES
Gaps between the chimney and flooring allow
unwanted air flow.
19
CONTROLLING AIR FLOW DUCT CHASES
Gaps between the ductwork and flooring allow
unwanted air flow as well.
20
CONTROLLING AIR FLOWRETURN DUCTS
Nearly every two story home with a central return
has this double problem
A leaky return duct sucks in hot attic air, and
an open bypass allows easy exit of that air.
21
LEAKY RETURN DUCTS
leak
Hot attic air enters your home in the summer!
22
AFFORDABILITY PROBLEMSDUCT LEAKAGE
CONTROLLING AIR FLOWPOOR BOOT CONNECTIONS
Boot connection
23
CONTROLLING AIR FLOW
If air is leaking out, it must also be leaking
in a vacuum cant be created under natural
conditions.
Courtesy of Southface Institute
24
CONTROLLING AIR FLOWONE OUT ONE IN LOTS AIR
FLOW
Homes have many fans inside of them. Lets look
at one that is often ignored the exhaust fan for
clothes dryers.

• 200 cfm (on average)
• 60 minute cycle
• 12,000 cubic feet out
• (from laundry room into dryer ? exhaust outdoors)
• 12,000 cubic feet in
• (from the holes with least resistance)

25
WHERE DOES AIR IN COME FROM?
Average size (2,000sq.ft.) home 18,000 cubic
feet As a result, just running the clothes dryer
for a 60 minute cycle will replace approximately
2/3 of all the air in the home.
Homes often have their laundry rooms situated
next to or near the garage. Dangerous fumes like
carbon monoxide could be pulled into your home
with unwanted air flow.
26
WHERE DOES AIR IN COME FROM?

• Carbon Monoxide poisoning is a leading cause of
  unintentional poisoning deaths in the U.S.
• Unintentional CO exposure accounts for an
  estimated 15,000 emergency department visits and
  500 unintentional deaths in the U.S. each year.
• Health effects of CO exposure include
• disorientation
• unconsciousness
• long-term neurological disabilities
• coma
• cardio respiratory failure
• death

Morbidity and Mortality Weekly ReportCenters for
Disease Control and Prevention
27
CONTROLLING AIR FLOWONE OUT ONE IN LOTS AIR
FLOW

• Heres another example
• 1,500 cfm
• 30 minute cycle
• 45,000 cubic feet out
• 45,000 cubic feet in

28
WHERE DOES AIR IN COME FROM?

• Your kitchen fans could be pulling dangerous
  fumes through your fireplace in the living room.

29
CONTROLLING AIR FLOWFANS/PRESSURES IN HOMES
Exhaust CFM
Clothes Dryers 150 250
Bath Exhaust Fans 50 100
Kitchen Exhaust Fan 100 1,500
Whole-House Fans 2,500 5,000
Central Vacuums 100
Fireplaces (pull in air for combustion) up to 400
Stack Affect (convection loop) 15 - 30
All these add up to 10,000s cubic feet of air
passing through walls, floors and roof
assemblies.
30
CONTROLLING THERMAL FLOW
31
CONTROLLING THERMAL FLOW
Driving Forces
Pressure
Heat
Moisture
Courtesy of Southface Institute
32
CONTROLLING THERMAL FLOW

• Heat can flow in and out of your home in several
  different ways
• Conduction
• Convection
• And Radiation

33
CONTROLLING THERMAL FLOWCONDUCTION

• Conduction is where heat energy is transferred
  from molecule to molecule by direct contact.

By sitting on a cold rock, your body heat will
transfer from you, to the rock through conduction.
34
CONTROLLING THERMAL FLOWCONVECTION

• Through convection, heat in a gas or liquid is
  transferred by the circulation of currents from
  one region to another.

35
CONTROLLING THERMAL FLOWRADIATION

• Through radiation, electromagnetic rays are
  emitted from the surface of an object due to its
  higher temperature as compared to its
  surroundings.

36
CONTROLLING THERMAL FLOW

• Mean Radiant Temperature (MRT) dominates comfort.
  
• (40 gt than ambient temp.)

So in other words If you lose control of surface
temperatures, you lose control of comfort!
Remember the conduction example we used earlier
if you sit on a cold rock, the heat from your
body will be transferred to the rock.
37
CONTROLLING THERMAL FLOWSURFACE TEMPERATURES
TOO COLD
Condensation on a window could be an indication
of temperatures that are too low to ensure
comfort.
38
CONTROLLING THERMAL FLOW
Most insulation is NOT an air barrier
39
CONTROLLING THERMAL FLOWTHE AIR BARRIER
EXPERIMENT
Consider your winter coat without the outer layer
(air barrier). The warm air your body heat
creates would flow out of your insulation, making
you very uncomfortable.
The lining keeps us warm, but the shell acts as a
separate air barrier and is needed to stop cold
air from flowing through the fibrous insulation.
40
CONTROLLING THERMAL FLOWWHY ALIGN THE AIR
BARRIER?
Without air barriers on all sides of insulation,
dropped ceilings are the perfect example of
unwanted air flow.
41
CONSIDER THE FORCES OF AIRFLOW ON YOUR HOME
Driving Forces
Pressure
Heat
Moisture
Courtesy of Southface Institute
Stack effect is a convective loop throughout the
entire house cause by differences in pressure.
42
CONTROLLING THERMAL FLOWWHY ALIGN THE AIR
BARRIER?
Heres an common example of air barrier
misalignment.
Dropped ceiling
43
CONTROLLING THERMAL FLOWWHY ALIGN THE AIR
BARRIER?
The air barrier (in this case, the drywall)
doesnt insulate, so radiation will heat the
surface of the dropped ceiling, warming the air
inside.
70o F
44
CONTROLLING THERMAL FLOWWHY ALIGN THE AIR
BARRIER?
The warm surface of the dropped ceiling created a
convective loop through the fibrous insulation
lining the attic.
70o F
45
CONTROLLING THERMAL FLOWWHY ALIGN THE AIR
BARRIER?
As warm air flows into the attic, cold air flows
back out (into the dropped ceiling) and lowers
the temperature.
46
CONTROLLING THERMAL FLOWWHY COMPLETE THE AIR
BARRIER?
Cold attic air
30o F
When convection loops are allowed between the
inside air and the attic, you lose control of
surface temperatures
30o F
50o F
70o F
Cold outside air
Warm inside air
70o F
This affects your comfort!
47
CONTROLLING THERMAL FLOWWHY COMPLETE THE AIR
BARRIER?
Infrared cameras like the one shown here can tell
us where air barriers or insulation are
misaligned or missing, by showing differences in
wall temperatures.
48
CONTROLLING THERMAL FLOWWHY COMPLETE AIR
BARRIER?
Here is a infrared image depicting the convection
loop within dropped ceilings which we just
discussed. Notice the misalignment of air
barriers by the differences in shading in this
thermal image.
Darker shades depict lower temperatures where
cold attic air is passing through fibrous
insulation.
49
CONTROLLING THERMAL FLOWINSULATION AIR BARRIER
The Bathtub is a common place to leave out air
barriers. This can cause major comfort problems
where tubs are situated next to exterior walls,
but is easily remedied with proper planning for
construction installation.
50
CONTROLLING THERMAL FLOWTUB WITHOUT AIR
BARRIER REVEALED
Bathtubs on exterior walls, like this one,
facilitate large amounts of conduction, allowing
heat to escape your home in the winter.
51
CONTROLLING THERMAL FLOWINSET STAPLING
MISALIGNMENT
Inset stapling of air barriers into interior
walls, as shown on the left, is one example of
misalignment, causing gaps and voids in the
insulation. This can cause comfort problems in
the home by allowing unwanted air flow.
52
CONTROLLING THERMAL FLOWBONUS ROOM OVER GARAGE
Summer
Conditioned Room
Garage Ceiling
Without proper insulation and an air barrier in
the floor, hot air flows in during the summer
53
CONTROLLING THERMAL FLOW BONUS ROOM OVER GARAGE

Winter
Conditioned Room
Garage Ceiling
and out during the winter.
54
CONTROLLING THERMAL FLOW BONUS ROOM OVER GARAGE

Improperly installed insulation can drop due to
gravity. This is a common problem in deep
cavities in your home.
55
CONTROLLING THERMAL FLOW BONUS ROOM OVER GARAGE

Heres another example of misalignment due to
dropped insulation.
56
CONTROLLING THERMAL FLOW BONUS ROOM FLOOR
PROBLEM
Courtesy of Fort Collins Utilities
57
CONTROLLING THERMAL FLOWCONDUCTION THROUGH
FRAMING
inside
outside
RippleCraft Log Homes
Thermal bridging occurs when materials that are
poor insulators (i.e. wood) come in contact with
each other as shown here, allowing heat to
radiate through.
58
CONTROLLING THERMAL FLOWCONDUCTION THROUGH
FRAMING
The infrared image on the right shows thermal
conduction where several wood studs are lined up
next to each other, rather than leaving room for
insulation. Notice the cooler temperature where
the studs are, indicating that heat is escaping
more easily through the wood.
59
CONTROLLING THERMAL FLOW
Ice damming, as shown here, is a direct result of
warm indoor air leaking from the house into the
attic. The warm air melts the snow which freezes
again when it drips to the cooler attic eaves.
Courtesy of Building Science Corp.
60
CONTROLLING MOISTURE FLOW
61
CONTROLLING MOISTURE FLOW
Driving Forces
Pressure
Heat
Moisture
Courtesy of Southface Institute
62
CONTROLLING MOISTURE FLOW

• While keeping the rain from leaking in your home
  is important, most moisture damage comes from air
  flow, because
• ALL air carries moisture.

63
CONTROLLING MOISTURE FLOW
Example 4 x 8 Sheet of Gypsum Board
Air leakage will ultimately lead to moisture
problems for your home. This is the volume of
water that enters a 1 square inch hole in your
home over the course of one heating season.
1 in. sq. hole
30 quartswater
Interior at 7F
64
CONTROLLING MOISTURE FLOWWHY MOISTURE IS A
PROBLEM
All action happens at surfaces
This means condensation on your windows, walls,
insulation, etc.
Lets take a look at how this happens
65
CONTROLLING MOISTURE FLOWWHY MOISTURE IS A
PROBLEM

• The dew point is the temperature at which air
  must be cooled for water vapor to condense into
  water.

The dew point changes based on the relative
humidity in the air
66
CONTROLLING MOISTURE FLOW
So, at a given relative humidity, and a given
barometric pressure, if the outside temperature
drops to the dew point (F), you will see
moisture, or dew, develop.
67
BUT HOW DOES THIS AFFECT MY HOME ON THE INSIDE?

• Great question!
• Holes and cracks allow inside warm air to reach
  an exterior sheathing surface.
• If the outside surface is below the 45F dew
  point, moisture will condense out of the air.

68
CONTROLLING MOISTURE FLOWACTION AT THE SURFACES
Without insulation, the inside temperature warms
the outside sheathing, keeping it above the dew
point
69
CONTROLLING MOISTURE FLOWACTION AT THE SURFACES
With insulation, the outside sheathing remains
cold (below the 45 dew point). If inside warm
air reaches the outside sheathing, the moisture
in the air will condense on the surface.
70
CONTROLLING MOISTURE FLOWACTION AT THE SURFACES
Inside 70F, 45F Dew Pt.
Outside 30F
55oF Warm Surface
34F Cold Surface
Therefore, you must control air leakage.
Wall cavity
71
CONTROLLING MOISTURE FLOWACTION AT THE SURFACES

• Crawlspaces provide perfect opportunities for
  condensation
• Driving forces push hot, humid air in this small
  basement to meet the cooler, conditioned spaces
  above. This image shows the damage that action at
  the surfaces can cause.

Courtesy of Building Science Corp.
72
CONTROLLING MOISTURE FLOWACTION AT THE SURFACES
Courtesy of Building Science Corp.
Combine moisture, wood, and the dark environment
inside the wall assembly and you have the perfect
conditions for mold and dry rot.
73
SOLVING PROBLEMS
The building science principles behind energy
efficient homes provide the basis for a
compelling value proposition. This section will
discuss these principles which ENERGY STAR uses
to create homes that are comfortable, durable,
affordable, efficient .
74
HOW TO APPLY BUILDING SCIENCEENERGY STAR
QUALIFIED HOMES
Air Sealing
Complete Air Barrier
Proper Insulation
Tight Ducts
Advanced Windows

Efficient Equipment
Right Sizing
Field Verification
75
PROPER INSULATION
76
PROPER INSULATION
There are no gaps, voids or compression here, and
the insulation is fully aligned with the interior
surface. Note that the insulation is also
carefully fit around piping and electrical
wiring.
77
PROPER INSULATION
This is an image of dense-packed cellulose
insulation. This insulation, mixed with water and
glue, is sprayed into wall assemblies through a
hose. The adhesive mixture prevents the
insulation from falling out or settling.
78
COMPLETE AIR BARRIERS
79
COMPLETE AIR BARRIERS
These builders have planned ahead for simple air
barrier details by making their framers
responsible for installing sheathing (e.g., dry
wall or plywood) at dropped ceiling locations
before they are framed.
Courtesy of Building Science Corp.
80
COMPLETE AIR BARRIERS
Air barriers behind the tub ensure proper
insulation.
81
COMPLETE AIR BARRIERS
Courtesy of Building Science Corp.
A thin sheathing material can be easily installed
on the attic side for a complete air barrier.
This prevents the hot wall in the summer and
cold wall in the winter.
82
AIR SEALING
83
AIR SEALING
Seal plumbing penetrations with caulking or
expanding foam and provide flashing where needed
for very large air spaces. In this image, only
caulking is needed because the plumber has neatly
cut the hole around the plastic pipe penetration.
Courtesy of Building Science Corp.
84
AIR SEALING
Courtesy of Building Science Corp.
Electrical boxes allow for a surprising amount of
air flow, especially with roughly cut drywall
holes. This can be avoided with special
electrical boxes that are self sealing, as shown
on the left, or with fully caulked air gaps
around neatly cut openings for traditional
electrical boxes as shown on the right.
85
TIGHT DUCTS
86
TIGHT DUCTS
DUCT BOOTS SEAMS SEALED WITH MASTIC
Sealing duct connections prevents loss of
conditioned air.
87
TIGHT DUCTS
GASKETED DOORS SEALED SEAMS
88
ADVANCED WINDOWS
89
ADVANCED WINDOWS
This keeps solar heat radiation out during the
summer and in during the winter.
Improved technology reduces heat transfer
Low-E glass reflects heat UV rays
Inert gas fills insulate better
Multiple panes insulate better
Warm edge spacers reduce heat flow condensation
90
ADVANCED WINDOWS
Winter Interior Images

• Infrared Camera

• Standard Camera

Standard Window
Low-E Window
Standard Window
Low-E Window
Warm
1/3 the heat loss!
Cold
Hot
91
ADVANCED WINDOWS
Pictures of furnishing fabrics after two-years
exposure
Without Low-E (emissivity) windows
With Low-E windows
New homebuyers often spend thousands of dollars
decorating their homes. Without high performance
windows that block damaging ultraviolet
radiation, these furnishings will fade and
degrade over time, as will window treatments and
carpeting.
92
EFFICIENT EQUIPMENT
93
EFFICIENT EQUIPMENT
As much as half of the energy used in homes goes
to heating and cooling. Therefore, equipment
plays a critical role in the efficiency of a
home. Efficient, properly sized HVAC systems
have Lower Cost Increased Efficiency Longer
Lifetime Better Moisture Control Improved
Comfort
94
RIGHT SIZING
95
RIGHT SIZING

• If a system is installed that is too large for
  the home, it not only costs more up front, but
  also operates less efficiently, and can cause
  comfort and humidity problems.
• Lets take a look at the efficiency of equipment
  as run-time is examined

96
RIGHT SIZING

• If a cooling system is oversized
• The inside temperature rises
• The system switches on
• The system works hard to blow huge volumes of
  cold air into the house
• The temperature drops quickly
• The system turns off

97
RIGHT SIZING

• If the cooling system is properly sized
• The inside temperature rises
• The system switches on
• The system works moderately to lower the
  temperature over a longer run-time
• The temperature drops steadily
• The system turns off

98
RIGHT SIZING
As run-time increases, the energy efficiency
ratio increases as well. Therefore, if the
temperature is lowered at a slower, steady pace,
energy use, and consequently, cooling costs, will
decrease significantly.
Right-Sized Equipment Lower Operating Cost

Energy Efficiency Ratio
Increase cycle time from 3 to 8 min.
Run-Time (minutes)
99
FIELD VERIFICATION
100
FIELD VERIFICATION
Blower Door Test
ENERGY STAR qualified homes are inspected and
tested by an independent Home Energy Rater to
meet EPA's guidelines for energy efficiency.
The Blower Door test measures how much air
leaks out of a homes envelope by studying at how
much air must be removed from the home to reach a
certain pressure level, thus testing the
efficiency of the building envelope.
101
FIELD VERIFICATION
Duct Blaster Test
Duct blaster test measures the leakiness of the
homes duct system. The average new American
home duct system has about 20-30 air leakage.
102
FIELD VERIFICATION
Infrared Camera Diagnostics
Many Home Energy Raters use infrared cameras to
pinpoint areas where heat and cold can escape
from a home so they can be sealed and properly
insulated by the builder.
103
HIGH PERFORMANCE HOMESPUTTING IT ALL TOGETHER
Affordable Comfortable Healthy Durable
Why
Control Moisture Flow
Control Thermal Flow
Control Air Flow
How
Driving Forces
Stack Effect
Fans
Conduction
Convection
Radiation
Bulk
Vapor
Proper Insulation
Proper Insulation
Low-E Windows
Air Sealing
Water Man. Roofs
Air Sealing
Air Sealing
Air Sealing
Low-E Windows
Low-E Windows
Radiant Barriers
Air/Vapor Barriers
Water Man. Walls
Air Barriers
Air Barriers
Air Barriers
Air Sealing
Tight Ducts
Water Man. Foundation
Tight Ducts
Min.Thermal Bridging
What
Air Barriers
Right-Sizing
Pressure Balancing
Ventilation
Tight Ducts
Dehumid.
104
EFFIECIENCY THROUGH ENERGY STAR
Effective Insulation
Tight Construction and Ducts
High Performance Windows
Efficient equipment
Third-party verification
Lighting and Appliances
105
Indoor airPLUS Program
EPA has also created the Indoor airPLUS program
to address indoor air quality in new homes. This
label requires that the home first qualifies as
ENERGY STAR, and then addresses several other
health and safety issues in the home.
106
CONSIDER ADDING ON THEENERGY STAR INDOOR AIRPLUS

• Radon Control
• Pest Barriers
• HVAC Systems
• Combustion Systems
• Materials

107
FOR MORE INFORMATION

• Visit us on the Web
• http//www.energystar.gov/homes
• Or call the ENERGY STAR hotline
• 1-888-STAR-YES