High Performance Affordable Homes

Building High
Performance Homes

Janet McIlvaine and David Beal
November 20, 2008
Mobile, Alabama

Welcome and Introductions
• Janet McIlvaine and David Beal
– Florida Solar Energy Center, Research Institute of UCF
– Lead 1 of 6 Department of Energy Building America Teams
– Building America Industrialized Housing Partnership (BAIHP)
– Research Analysts
• Brenda C. Lawless and Brian Stanley
– Mobile County Habitat for Humanity
– Partners in Building America's Gulf Coast High Performance
Demonstration Housing Project
• HBA of Metro Mobile
– Promotional Partner

3

DOE Building America Program
• www.buildingamerica.gov
• Public-Private Research Initiative
• Public: DOE funded teams of researchers
• Private: Home builders across America
• Cost Shared Research:
– Build high performance houses together
– Document problems and solutions
– Conduct training to spread lessons learned

4

Building America Goals
• Move standard practice toward “High Performance”
• Climate specific solutions
• Work in key markets
• With production builders
• Produce whole communities
• Systems engineering approach
– aka “house as a system” or “whole house” approach
• Transfer “Lessons Learned” to other builders
– Workshops, documents, case studies

5

DOE Building America Program
• “High Performance” Goals
– 30-70% energy savings (Mobile goal ~30% savings)
– First year positive cash flow
– While improving indoor air quality, durability, and
comfort
– How is this possible…

6

BAIHP is estimated to save over $14,000,000/yr in 168,000+ homes

G.W. Robinson
Lakeland Habitat
For Humanity

7

G.W. Robinson Builders, Inc. – Gainesville, FL
• Progressively increased energy efficiency over time
• HERS Index <70 saving ~ 30% on a whole house basis
• 400+ Houses completed and sold
• Lead – Florida H.E.R.O. (Ken Fonorow)
• Detailed Case Study: www.fsec.ucf.edu/en/publications/pdf/FSEC-PF-430-
07.pdf

8

• 1st year positive cash flow
First Cost Annual Cost
(7%, 30 yr mortgage)

Total Incremental Cost $2,021 $161
(includes 10% mark up)
Estimated Annual Energy $863
Savings (wrt typical)

Net 1st Year Cash flow $702

9

• Heating/Cooling Equipment features
– SEER 15 Air conditioner, 93% AFUE Gas Furnace
– ACCA Manual J system sizing
– Ducts sealed with mastic and tested
– Interior air handler closet
• Water Heating Equipment
– EF=0.84 Tankless gas water heater
• Heating/Cooling Load Reduction Features
– Energy Star Windows (0.28 SHGC, U=.39 Vinyl Low-e)
– R-30 with Radiant barrier vented attic
– 2 x 4 Advanced Framing w/R-13 cellulose
– Wide Overhangs on Patio doors and windows
– Passes Energy Star Thermal Bypass Inspection
• Indoor air quality, durability, and comfort features
– Ducted kitchen and bath exhaust fans
– Passive, positive pressure outside air ventilation
– Drainage plane and flashing details
– Passive return air pathways from bedorooms
– Low VOC paints
• Verification
– Blower door and duct leakage testing
10

Lakeland Habitat for Humanity – Lakeland, FL
• Goal: Cost Effectively Exceed Energy
Star
• Builder Motivation – Reduce total cost of
ownership
• Started with Energy Star ’99 in 2001,
progressively improved
• HERS Index = ~70 saving about 30% in
whole house energy use
• Understand Builder Needs:
– Volunteer Friendly
– Proven
– Readily Available
– No Maintenance Burdens
• Estimated First Cost Increase: $2000
• Detailed Case Study:
www.baihp.org/habitat/pdf/Lakeland-
Habitat-Case-Study.pdf 11

• 1st year positive cash flow
Annual Cost
(0%, 20yr HFH
First Cost
mortgage)
Total Incremental
$2,000 $100
Cost
Estimated Annual
$250
Savings
Net 1 st year cash
$150
flow to owner

• $5000 grant from city for meeting energy standards
12

• Heating/Cooling Equipment
– SEER 14, HSPF 8+ Heat Pump sized with ACCA Manual J
– Duct system sealed with mastic and tested
– Interior air handler closet, ducted central return
• Heating/Cooling Load Reduction
– R-30 Ceiling and R-13 Wall Insulation
– Passes Energy Star Thermal Bypass Inspection
– Radiant Barrier below roof decking
– Infiltration control (house wrap air barrier + extensive air
sealing)
– Energy Star Windows shaded by overhangs, Porches & shade
trees
• Appliances & Lighting
– Water heater timer
– Energy Star Refrigerator
– 20% CFL Lighting
• Indoor air quality, durability, and comfort features
– Ducted kitchen and bath exhaust fans
– Passive, positive pressure outside air ventilation
– Drainage plane and flashing details
• Verification
13
– Blower door and duct leakage testing

“Systems Engineering” Approach to Change

Evaluation
& Planning

“Lessons learned”
Translated into
case studies,
publications, &
“Best Practices”
documents

14

Systems Engineering Approach
• More Case Studies & free BA resources online:
– www.baihp.org
• Case studies, publications, and presentations
– www.baihp.org/habitat
• Habitat specific information
– www.baihp.org/gulfcoast
• Demonstration project summary
– www.buildingamerica.gov
• Best practices, program overview, searchable database of
publications
15

Systems Engineering Concepts

• “House as a System” thinking
– As we make improvements, make sure we aren’t creating
new problems
• Involve whole construction team
• Anticipate and solve common problems on paper
• Reduce call backs by evaluating warranty claims
• Work with “off the shelf” products
• Seek first year positive cash flow
• Prototype, evaluate, and refine solutions
16

150

{
Building America Technical Assistance 140
Existing Homes
130

• Partner steps toward reaching 30% 120

whole house savings goal 110

– First – Preliminary Evaluation IECC 100

• Combustion Safety 90
Energy Star 85
• Warranty Issues 80

• Energy Code Compliance Building America
Demonstration Goal 70-75 70
• Begin “Systems Engineering” process
60

– Next - Energy Star for Homes HERS Index Scale
A house compliant with the 50
• HERS 85 + prescriptive req’s International Energy
Conservation Code (IECC) 40
• Ensure no IAQ, durability, comfort problems scores 100, each point
lower = 1% whole house 30
– Next – Exceed Energy Star savings compared to IECC
20
• HERS 70-75
10
• Ensure no IAQ, durability, comfort problems 17
Zero Energy Home 0 0

Systems Engineering Process
• Preliminary Evaluation Evaluation
& Planning
• Set Energy Savings Goal - IECC? Energy
Star? Beyond Energy Star?
• Develop a package of improvements
• Work with project team to anticipate and
solve problems before implementation.
Prototype and refine individual
improvements, if necessary
• Build a TEST house
• Refine package as needed
• Integrate into production process
This is the process we used for 18
GC Demonstration Houses…

Project Introduction:
Building America’s Gulf Coast High Performance
Affordable Housing Demonstration Project

Gulf Coast High Performance Affordable Housing
Demonstration Project Goals
• 30% whole house energy savings
– Proven results in Florida, but in a new market
– Technical assistance alone did not attract much interest
• Demonstration houses show case…
– NOT cutting edge technology
– BUT an achievable, replicable high performance
package that most builders can adapt to their houses
• Affordable housing focus to emphasize feasibility
20

DOE Gulf Coast High Performance Affordable Homes
• http://www.baihp.org/gulfcoast/
• Goals
– HERS Index 70-75
– $2,000 first cost
– First year positive cash flow
– Meets Indoor Air Quality, Durability, and Comfort Criteria
– Conduct local builder training
• Four Builder Partners
– Habitat for Humanity Affiliates
– Baton Rouge, New Orleans, Slidell, and Mobile
21

East St. Tammany Habitat (Slidell)
New Orleans Area Habitat

Habitat of Greater Baton Rouge

Mobile County Habitat

22

First Year Positive Cash Flow

Annual Cost Annual Cost
First Cost (0%, 20yr HFH (7%, 30 yr
mortgage) Mortgage)
Total Incremental
$2,000 $100 $144
Cost
Estimated Annual
$250 $250
Savings
Net 1st year cash
$150 $106
flow to owner

23

150
Typical
Gulf Coast High Performance Existing 140
Homes
Affordable Homes – Systems 130

Engineering Process 120

New Orleans
110

• Preliminary Evaluation IECC Slidell
100

Mobile
– IAQ, Durability, Comfort, and Energy Baton Rouge
90
Energy
(HERS Index) Star 80

Project
• Identify “Package” & Develop Goal 70

Strategies 60

• Build a Trial House (Afternoon Tour) 50

40
• Refine Package
30

• Build Demonstration House 20
HERS Index
• Conduct Training with Home Comparison -
10
Standard
Zero
Building Industry Construction 24
Energy 0

Home

Systems Engineering Approach
• Avoidable IAQ, Durability, and Comfort Problems …
– Combustion safety issues
• Flame roll out and exhaust back drafting
– Asthma/allergy triggers
• Pollen, roach dander, dust mites
– Bulk water and humidity issues
• Biological growth, buckling, bulging, sagging, standing water, rusting, shorting
electrical connections, water logged materials and fixtures, wet insulation,
condensation
– Comfort
• “My bedroom/kitchen/family room never gets cool/warm”
• Many of these issues are driven by the same dynamics of air, heat,
and moisture/water movement
25

Building Science
Fundamentals

Building Science Back Ground
• Our building science scope…
– Energy use and efficiency, indoor air quality (IAQ),
durability, and comfort
• Dynamics and management of air, heat, &
moisture/water
• Outside our scope…
– Structural integrity – engineering
– Life safety (including disaster resistance) – codes
27

Typical Energy Use Profile
Average Annual Energy Use
Measured in 10 Florida Habitat Homes

19.6% Other
40.7%
Heating &
7.9%Refrigerator
Cooling
8.6%Dryer
4.4% Stove
18.7% Water Heating

28

Typical Energy Use (& Conservation) Profile

• 40% = Heat and Cooling
– Efficient Equipment – Mechanical system
– Load Reduction - Enclosure
• 20% = Water Heating
– Efficient Equipment
• 20% = Appliances (stove, dryer, refrigerator)
– Energy Star Appliances
• 20% = “Other” including lighting
– Efficient Lighting
29

Building Science Back Ground
• Air, heat, moisture, and water often move together
• By controlling movement, we control
– Indoor air quality
• Example: entry of outside pollutants, soil gases
– Durability
• Example: path of rain over building materials, indoor humidity levels
– Comfort and energy efficiency
• Heat gain and loss, air flow in each room, humidity levels
– Multiple benefits from individual improvements
• Example: infiltration control
• Creating a “controlled” environment
30

Building Science Terms
• Conditioned space
Uncond.
– Controlled environment – inside
Outside
• Unconditioned space
Conditioned
– Less controlled environment – attic,
crawl spaces
Un/Conditioned
• Outside
– Uncontrolled environment - outside
• Building enclosure (“envelope”)
• Mechanical system
31

Movement of Air, Heat, Moisture and Water
• Building enclosure
(“envelope”)
– Boundary
– Materials and assemblies
• Foundation, floor, walls, roof &
ceiling
– Air barrier + thermal barrier +
drainage plane
– Controls air, heat, and water flow
– how…?
• Mechanical system
– Moves air, removes heat and
humidity
– Heating/Cooling + ventilation +
exhaust fans
32

Movement of Air, Heat, Moisture, & Water
• Air, heat, and moisture move in response to
differences…temperature or pressure

• Direction of Movement…
– “High” goes to “Low”
– Air moves from high pressure or temp toward low
• Air barrier stops it
– Heat moves from high temp toward low temp
• Thermal barrier stops it
– Water moves from high ground toward lower
• Drainage plane and flashing direct it 33

• House is full of air
– 1 cfm “in” = 1 cfm “out”
– Every 1 cfm exhausted is replaced by 1 cfm
• Example: Box fan in window

34

• To have movement, need three things…
– Air/heat/moisture + hole + driving force
• Example: Drinking straw

35

Control Movement of Air, Heat, Moisture, & Water
• To control flow…
– Minimize source
• Nearly impossible
– Minimize holes
• Continuous boundaries between source & cond. Space
• Air barrier + thermal barrier + drainage plane
• At joints and penetrations…ship lap and/or seal
– Minimize driving forces
• Can’t eliminate temperature difference
• Maintain neutral air pressure 36

Controlling Water, Air, and Heat
Principal Strategies
Water:
•Dry Materials
•Continuous Ext. finishes
•Continuous Drainage Plane
•Flashing
•Assemblies that Dry
•Exhaust wet air
Air:
•Continuous Air Barrier
•Sealed Duct System
•Neutral Air Pressure
Heat:
•Continuous, Even
Layer of Insulation

37

Siding and Shingles are first line of defense against liquid water
Continuous drainage plane behind vented (vinyl, wood, fiber cement) siding.
House Wrap Rigid Insulation
Tar Paper/Felt (sealed at edges (T&G or sealed at
(Ship lapped) and seams) edges and seams)

38

Water:
•Dry Materials
•Exterior finishes
•Flashing
•Exhaust wet air
Air:
Heat:
•Continuous, Even
Layer of Insulation

39

All these materials are drainage planes.
Which are also air barriers?

40

All these materials are drainage planes.
Which are also air barriers?

Is NOT an Air Barrier IS an Air Barrier IS an Air Barrier
41

Continuous Air Barrier
• Controls Air Flow and Air Transported Moisture Flow
– Separates conditioned space from unconditioned
– Surrounds and contains “conditioned space”
– Elements
• Slab/floor decking
• Sill seal or equivalent
• House wrap or
• Rigid insulation sealed at edges and seams
• Top plates (exterior AND interior walls)
• Ceiling drywall
• Sealant in penetrations of above surfaces
• Ducts and air handler, if in unconditioned space…

42

Sealed Duct System
• Duct system in unconditioned spaces is part
of the house air barrier
• Each duct surrounds little piece of
conditioned space
• Air handler is part of the air distribution
system
• Special conditions in ducts
– Very high pressure in supply
– Very low pressure in return
– Both in air handler
– Very cold/hot air in supply
– High potential for changing house air pressure
43

Unbalanced house air pressure
• Duct leakage can lead to uncontrolled air flow
– From out to in, from in to out, and both at the same time
– can heighten natural infiltration significantly
– Can cause whole house depressurization or pressurization
– Can lead to combustion safety issues, so can other causes of
house depressurization such as…
• Exhaust fans
• Closed interior doors (without ducted returns)
• (Demonstration of Air Flow Dynamics after break)

44

What
combustion
safety problem?

45

Water is a byproduct of combustion
• 1 cubic foot natural gas
releases 1000 Btus
• 100K Btuh furnace burns
about 100 cuft/hr
– About 200 cuft water vapor per
hour
– Slightly more than 1 gallon
water per hour
• Typical Btuhr Input
(residential)
– Furnace 50K-200K
– Water Heater 30K-75K
– Ranges 10K-15K 46

Naturally Aspirated
Combustion Equipment

47

• And now we pause for a demonstration of air flow
dynamics…and combustion safety discussion

48

Combustion safety problems
produced by space depressurization

Incomplete Combustion
Normal Draft Spillage Backdraft Flame Rollout
CAZ wrt Out
CAZ wrt Out CAZ wrt Out CAZ wrt Out CAZ wrt Out
-15
0 -5 -8 -25 pascals
pascals
pascal pascals pascals

49

Prevent combustion safety problems…
• Switch to non-atmospherically vented equipment
• Make combustion “zone” completely connected to
unconditioned space or outside AND completely
separated from conditioned space by a continuous
air barrier and thermal barrier
• Always provide combustion “zone” with adequate
(idiot proof) combustion air using the National
Gas Code guidelines
50

80%, mid-
efficiency or
induced draft
furnace

51

Direct Vent Water Heater

52

Sealed Combustion Condensing 90%+ AFUE
Furnace

53

All Air From Inside the Building
Example:
• Furnace = 100,000 btu/hr input
• Water heater = 34,000 btu/hr
input

• Total btu/hr = 134,000 btu/hr
input

134 sq.in.
• 1 square inch per 1,000 btu/hr
input required.
134 sq.in.
34k
100k • 134,000 / 1,000 = 134 square
inches for each opening.
• One within 12 inches of ceiling &
one within 12 inches of the floor.
55

All Air From Outdoors. Method 1a - Vertical
• Example:
input
12” max
12” max
33.5 sq.in.
input
33.5 sq.in.
34k • 1 square inch per 4,000 btu/hr
100k 12” max
12” max input required.

• 134,000 / 4,000 = 33.5 square
Figure M703.2(b) 56

All Air From Outdoors. Method 1b - Horizontal
Example:
input

12” max • Total btu/hr = 134,000 btu/hr
12” max
67 sq.in. input
67 sq.in.
input required.
34k
100k
12” max
12” max
• 134,000 / 4,000 = 67 square
Figure M703.2(c)
57

All Air From Outdoors. Method 2
• Example:
input
44.7 sq.in.
~OR~
12” max
12” max
44.7 sq.in. input

input required.
34k
100k
• 134,000 / 4,000 = 44.7 square
• Within 12 inches of ceiling
Figure M703.2(d)
58

Whole house air pressure
• For Hot Humid Climate
– Negative House Pressure – Bad
– Neutral House Pressure – Good
– Positive House Pressure – Better
• Causes of negative house air pressure
– Exhaust fans
– Closed interior doors
– Supply duct leakage
– Supply duct leakage > return duct leakage
• To induce slight positive pressure…
– Small amount of filtered, controlled outside air
59

• Air barrier and duct system holes are hard to see, but
can be measured with a testing equipment.
60

Water:
•Dry Materials
•Exterior finishes
•Flashing
•Exhaust wet air
Air:
Heat:
•Continuous, Even
Layer of Insulation

61


62

Thermal Barrier
• Install in a continuous, even layer
• Missing insulation isn’t seen, it’s felt.

• Like a hole in your coat.
63

Building Science Summary
• Driving Forces
– Temperature difference
– Pressure difference
• Control Boundaries
– Air barrier, sealed duct system, thermal barrier,
drainage plane
• Energy Star for New Homes
– Thermal Bypass Inspection covers air and heat flow!
– www.energystar.gov 64

Step 1 – Achieve Energy Star
• Home energy rating system index
• Energy star program overview and technical
requirements
• Thermal bypass inspection
• Overview of Afternoon Field Activities

65

Preliminary Evaluation
• The HERS Index
• HERS=Home Energy Rating System
• Compares a “designed” or “as built” home
• To the HERS “Reference Home”
– same size, wall areas, structural system, fuel
– Minimum efficiency equipment
– Insulation etc to comply with 2004 International
Energy Conservation Code (IECC)
66

150

{ 140
Existing Homes
130

120

115 New Orleans

Preliminary 110

IECC 100 99 Slidell
HERS Index 95 Mobile
90 Baton Rouge
90

Evaluation for Energy Star 85
80
Building America
Demonstration Demonstration Goal 70-75 70

House Partners 60
HERS Index Scale
A house compliant with the 50
International Energy
Conservation Code (IECC) 40
scores 100, each point
lower = 1% whole house 30
savings compared to IECC
20

10
67
Zero Energy Home 0 0

Achieve Energy Star
(Part 2)

1

Step 1 - Achieve Energy Star
Outline of Process…
1. Learn about Energy Star
2. Find a rater
3. Become a partner
4. Preliminary Evaluation (by rater)
• Critical Changes (Combustion Safety, Durability,
Call Backs)
• HERS Index
• Prescriptive Requirements
• Thermal Bypass Inspection
• Infiltration Test
• Duct Leakage Test
5. Review Raters Recommendations and Select an
“Improvement Package”
6. Build an Energy Star House
1. Preconstruction: Design, Specs, Prelim HERS Index
2. Construction: Quality Assurance, Thermal Bypass
Inspection
3. Post Construction: Testing, Final HERS Index,
Paper work
7. Rater Registers your Energy Star house, gives
you a certificate - when you reach Energy Star –
write a press release!

• What next? Decide what to implement in
production, add details to plans and specs,
training
2

Step 1 - Achieve Energy Star
Outline of Process…
1. Learn about Energy Star
2. Find a rater
3. Become a partner
4. Preliminary Evaluation
• Critical Changes (IAQ, Durability, Call Backs)
• HERS Index
• Prescriptive Requirements
• Thermal Bypass Inspection
• Infiltration Test
• Duct Leakage Test
5. Review Raters Recommendations and Select an
“Improvement Package”
6. Build an Energy Star House
1. Preconstruction: Design, Specs, Prelim HERS Index
2. Construction: Quality Assurance, Thermal Bypass
Inspection
3. Post Construction: Testing, Final HERS Index,
Paper work
7. Rater Registers your Energy Star house, gives
you a certificate - when you reach Energy Star –
write a press release!

• What next? Decide what to implement in
production, add details to plans and specs, train
volunteers
3

• The HERS Index
• HERS=Home Energy Rating
System
• Compares a “designed” or “as
built” home
• To the HERS “Reference Home”
– same size, wall areas, structural
system, fuel
– Minimum efficiency equipment
– Insulation etc to comply with 2004
International Energy Conservation
Code (IECC)
– Reference house has a HERS Index
of 100

5

HERS Index
• Comparison of projected energy
use of your house to the 2004
International Energy Code

Your
House
98

6

HERS Index
• Projected energy use of your
house for..
– Heating, Cooling, Water Heating,
Appliances, Lighting, and “Other”
• Compared to 2004 IECC

19.6% Other
40.7%
Heating &
7.9%Refrigerator
Cooling
8.6%Dryer
4.4% Stove
18.7% Water Heating

7

HERS Index
• Rater Needs equipment
characteristics
– Fuel – gas/elec
– Size - capacity
– Location – cond/uncond
– Efficiency

19.6% Other
40.7%
Heating &
7.9%Refrigerator
Cooling
8.6%Dryer
4.4% Stove
18.7% Water Heating

8

HERS Index
• Heating and Cooling Energy Use
• Driven by heat gain/loss

9

HERS Index
• Rater needs “enclosure”
characteristics
• Location
• Dimensional characteristics
• Materials/assemblies
• Window characteristics
• Also test results
– Duct leakage – mandatory
– Infiltration – optional

10

Duct Leakage
• Limit 6 cfm of air leakage
• to the outside
• per 100 sq ft of conditioned space
• at the test pressure of 25 pascals

12

Duct Leakage
• Typical leakage sites…

13

Duct Leakage
– Plenum to Air Handler Connection

14

Duct Leakage

Air Handler Cabinet Joints
In Unconditioned Spaces

Building Cavities
As Ducts

15

Duct Leakage

Duct System Joints in
Unconditioned Spaces

16

Energy Star Qualified
Products
• www.energystar.gov
• Select “Products”
– Windows, Heating/cooling,
Appliances, Lighting

18

Thermal Bypass Inspection

Rater inspects integrity of…
• Air Barrier
• Thermal Barrier
• Alignment of the two

20

Thermal Bypass Inspection
• Quality of the “enclosure”
• Eliminating
– common “holes” in air barrier
– common bypasses around insulation

21

1.1 AIR BARRIER AND THERMAL ALIGNMENT

Generally, the Thermal Bypass Inspection Checklist requires a sealed air-barrier on all six sides of
insulation (top, bottom, back, front, left, and right), however, there are a few exceptions as noted
throughout the checklist. In Climate Zones 1 thru 3, there is a general exemption for the internal air
barrier closest to conditioned space because the predominant direction of air-flow in hot climates is
from the outside to the inside of the house. In Climate Zones 4 thru 6, the most critical air-flow is
from inside the home to the outside during cold weather, therefore the internal air barrier is
required.

Image courtesy of Southface Energy Institute

Figure 1.1.3 - The air barrier should be contiguous and continuous over the entire building
envelope. Insulation should be perfectly aligned with the air barrier.

In order for insulation to be an effective thermal barrier, it should be installed without any gaps,
voids, compression, or wind intrusion. Gaps and voids allow air to flow through the insulation,
decreasing its effectiveness (Figure 1.1.4). Compression reduces the effective R-value of the
insulation.

Figure 1.1.4 - Gaps (left) and voids (right) allow air to flow through insulation.

The following images depict misalignment between the air barrier and insulation that undermine the
performance of the thermal enclosure.

24

1.1 AIR BARRIER AND THERMAL ALIGNMENT

KEY POINTS

Installation Criteria:
• Insulation shall be installed in full contact with the air barrier on all six sides to provide
continuous alignment with the air barrier. For example, batt insulation shall be cut to fit
around any wiring, pipes, or blocking and shall be correctly sized for wall width and
height.
• Climate Zones 1 thru 3 are not required to have an inside air barrier at exterior wall
assemblies since the predominant driving force in hot climates is from outside to inside.
• Two general exceptions to the requirement for a six-sided air barrier with insulation are
at band joist insulation and at the top of ceiling insulation. Although a significant
performance advantage is realized where a six-sided assembly is provided (e.g. SIPs),
band joist insulation is only required to be in contact with the exterior framing and any
exposed edges, and ceiling insulation is only required to be in contact with the air-
barrier below (e.g. the ceiling sheetrock) and at any exposed edges. This is due to
current cost effectiveness concerns with traditional construction practices. As a best
practice, air barriers at band joists are discussed further in Section 1.5.

Tips and Best Practices:
• When choosing insulation, consider options that most readily achieve the proper
installation requirements.
• Verify that insulation subcontractor installers are trained and/or certified in proper
installation practices.

25

Bad Insulation Installation

Good Insulation Installation

26

1.3 ATTIC EAVE BAFFLES

KEY POINTS

• Solid baffles shall be provided at all framing bays with soffit vents to prevent wind
washing at attic insulation.

• Even if soffit vents are not continuous, wind baffles are strongly recommended at all
framing bays since air gaps commonly occur between roof sheathing and the fascia
board. This can allow wind intrusion along the entire roof edge.

28

“Dam” for blown-in foam,
cellulose, and fiberglass

29

2.1 WALL BEHIND SHOWER/TUB

KEY POINTS

• Exterior walls shall be enclosed on all six sides, including a complete and continuous
air barrier behind the tub. An exception is provided for Climate Zones 1 thru 3 where as
an alternative to the inside air barrier, the builder can install a fully sealed and
continuous exterior along with RESNET Grade 1 insulation fully supported.

• Use a material that is readily available to ensure the air barrier is installed prior to
setting the tub. Plywood, oriented strand board (OSB), sheathing boards, and drywall
are good choices.
• Using spray foam at framing behind tubs is also an option to avoid labor installing both
air barrier and insulation. However, it will need to be installed prior to setting the tub or
shower.
• Insulation material and air barrier sheathing should be made available on site for
installation by the framing subcontractor prior to plumbing rough-ins, or the framing
subcontractor could install an air barrier behind the tub with the wall cavity left
accessible for installation of loose fill or blown-in insulation by the insulation
subcontractor.

31

4.1 DUCT SHAFT

KEY POINTS

• Openings to unconditioned spaces shall be sealed with solid blocking as required and
any remaining gaps shall be sealed with caulk or foam.

• Since the flashing or framed caps at shafts and penetrations are typically installed by
the framing subcontractors before the HVAC trades do their work, make sure
subcontractors understand the importance of complete air barrier assemblies.
• Use mastic to seal cracks and gaps.

Not sealed

Well Sealed
33

4.2 PIPING SHAFT/PENETRATIONS

KEY POINTS

• Openings to unconditioned spaces shall be sealed with solid blocking as required and
any remaining gaps shall be sealed with caulk or foam.

• Work with plumbing and electrical subcontractors to make the smallest openings
needed for penetrations.
• Since the flashing or framed caps at shafts and penetrations are typically installed by
framers before the plumbing and electrical trades do their work, make sure
subcontractors understand the importance of complete air barrier assemblies.

Sealed
Unsealed

35

5.1 ATTIC ACCESS PANEL

KEY POINTS
• Attic access panel shall be fully gasketed for a snug fit.
• Attic access panel shall be fitted with insulation (minimum of R-5) that fits snugly in the
framed opening.

• To increase durability, consider using a pre-insulated door panel or SIP panel for the
attic access panel.

5.2 ATTIC DROP-DOWN STAIR

KEY POINTS

• Attic drop-down stair shall be fully gasketed for a snug fit. However, gaps in weather-
stripping to accommodate hinge hardware shall be acceptable.
• Attic drop-down stair shall be fitted with minimum R-5 insulation that fits snugly in the
framed opening or firmly covers the opening.

• Factory made attic drop-down stair assemblies that are fully gasketed and include a
rigid insulation panel much like an exterior insulated door are a great simple solution
(see Figure 5.2.5 below).

37

5.4 RECESSED LIGHTING FIXTURES

KEY POINTS

• All recessed lighting fixtures to unconditioned attics shall be “insulation contact, airtight
rated” (ICAT), and shall be sealed to drywall with gasket, caulk, or foam.

• Consider using non-recessed lighting fixtures at all attic/ceiling interface locations
where appropriate to design preferences.
• Install recessed lighting fixtures in dropped ceilings with a complete air barrier
assembly above.
• Use ICAT fixtures that do not have air gaps in the housing assembly and with built-in
gaskets .
• Where ICAT fixtures are selected that come with air gaps in the housing assembly,
manually seal the gaps on the job site. However, manufacturer recommendations must
be followed since lighting fixtures get very hot.
• Recognize that ICAT recessed lighting fixtures are only needed at ceilings adjoining
unconditioned space.
• If gaskets are not built-in, develop a system for storing trim seal gaskets provided by
the manufacturer after initial installation of the recessed cans so they are available at
the end of the job.

39

Energy Star Performance Path Summary
Thermal Bypass Checklist:
http://www.energystar.gov/ia/partners/bldrs_lenders_raters/dow
nloads/Thermal_Bypass_Inspection_Checklist.pdf

Guide to the Thermal Bypass Checklist:
nloads/TBC_Guide_062507.pdf

Remember that many of the items on this checklist do not
pertain to Habitat construction because of the simplicity of the
floor plans. Concentrate on items 1.1, 1.3, 2.1, & 5.1 (or 5.2 if
attic stair) + 5.4 for can lights. Upon closer inspection, we may
find another item or two that applies to your design, but it's not
likely.

Review this material explaining the Performance Path for
reaching Energy Star:
nloads/PerfPathTRK_060206.pdf

Note that in addition to the TBC Inspection, there are several
other prescriptive requirements included in the Performance
Path:

•Sizing the HVAC system using Manual J (footnote 7 of perf.
path)
•Duct leakage 6cfm/100 sq ft of conditioned space or less
•Energy Star certified HVAC or windows or 5 appliances:
http://www.energystar.gov/index.cfm?fuseaction=find_a_prod
uct.)
40

Going forward…
• Building America - High Performance
Affordable Demonstration Houses:
www.baihp.org/gulfcoast
• Building America – Habitat Partnership
• Energy Star New Homes Program
– www.energystar.gov click on “New Homes”
• Local Home Energy Raters
– http://www.natresnet.org/directory/raters.aspx
– Look for the “Volunteer Rater” emblem
• Building America Best Practices Documents
– www.buildingamerica.gov (right hand margin)
– janet@fsec.ucf.edu and david@fsec.ucf.edu
– please include “Habitat” in your subject line
– 321-638-1434 and 321-638-1433

41

Introduction to the
Gulf Coast Demonstration Homes
(Part 3)

High
Performance Package
• Comfort & Energy Strategies
– Provide even comfort
– Reduce direct energy use
• Cooling & Heating Efficiency
• Appliances & Lighting
Efficiency
– Reduce Cooling & Heating
Loads
• Reduce Heat gain/loss
• Control air flow and humidity
• IAQ Strategies
– Prevent death & aggravation of
common health conditions
• Durability Strategies
– Protect equipment, materials,
assemblies
2

Improvement: Switch from attic mounted electric resistance
heating to minimum efficiency heat pump (SEER 13 HSPF 7.7)
• Savings :
• 7.8% for attic air handler
• 7.1% for interior closet.
• 800 to 900 kWh
• $108 to $96 per year.
• Discussion: Although these units will
save energy, homeowners used to gas
furnaces or electric resistance heating
may not like heat pumps due to the
cooler temperature of the air supplied
to the rooms. If the units are not sized
correctly and commissioned carefully
they may be prone to freeze-up in the
winter, causing them to go into
defrost mode more often than they
should, causing excessive energy use
3
and comfort complaints.

Improvement: Increase amount of fluorescent lighting from
10% to 75%. CFL bulbs meet requirement.
• Savings :
• 5.5%
• 616 kWh
• $74. .
• Discussion: First costs are higher than incandescent
bulbs, but the life expectancy of these bulbs is
significantly longer than incandescent bulbs. Not only
do fluorescent bulbs use less energy per lumen
produced, they also do not have as much waste heat
production as incandescent bulbs, lowering A/C loads
in the summer. There may be disposal issues, as CFLs
have mercury in them. Home Depot has a CFL
recycling program in all of their locations. EPA fact
sheet on CFL disposal:
http://www.energystar.gov/ia/partners/promotions/cha
nge_light/downloads/Fact_Sheet_Mercury.pdf

4

Improvement: Replace refrigerator with ENERGY
STAR refrigerator.
• Savings:
• 3.5%
• 355 kWh to 395 kWh
• $43 to $48.
• Discussion: The default refrigerator used for
calculations is rated at 775 kWh per year,
which may be higher than the smaller sized
HFH type refrigerator. Whirlpool’s donated
ENERGY STAR refrigerator uses 380 to 420
kWh per year (depending on which unit is
selected) If this refrigerator only saves 15% of
refrigerator energy (definition of ENERGY
STAR appliance), then this represents a savings
of approximately 90 kWh per year, or $11
5

Improvement: Increase heat pump efficiency from
SEER 13, HSPF 7.7 to SEER 14, HSPF 8.5
• Savings:
• 3.2%
• 275 kWh
• $33
• Discussion: If replacing SEER 13 straight
cool with strip heat, the savings is between
1075 kWh and 1175 kWh per year, or $129
to $141 per year. HVAC contractors have
reported that SEER 14 units are about the
maximum efficiency that can be reached
without using expensive and complicated
technologies such as multi-speed fans and
variable speed or multiple compressors.
6

Improvement: Install air handler in a sealed interior
closet, not the attic.
• Savings:
• 1.9%
• 216 kWh
• $26
• Discussion: This improvement also
affects indoor air quality and
longevity of the air handler. By
installing the unit in the conditioned
interior the unit is not subjected to the
extreme temperatures found in attics,
with less wear and tear on the unit.
Any air leakage found in the air
handler will not pull in dirty attic air,
improving IAQ, and lengthen the life
of the air handler by keeping the coils
cleaner. 7

Improvement: Use radiant barrier (RBS) decking for
roof (as opposed to non-RBS decking)
• Savings:
• 1.9%
• 208 kWh
• $25
• Discussion: All affiliates
building demonstration houses
were already installing RBS
decking. These savings
numbers would be higher if
attic installed air handlers are
used, but the Building America
team does not recommend attic
installed air handlers.
8

Improvement: Decrease duct leakage from the
national average to “essentially leak free” (Qn =
0.08 to Qn = 0.03)
• Savings:
• 1.0%
• 115 kWh
• $14
• Discussion: This improvement has many
advantages beyond saving energy. Duct
leakage is one of the driving forces behind
infiltration of outside air into a house. Duct
leakage causes pressure imbalances in a house,
which leads to increased infiltration. Increased
infiltration causes a degradation of indoor air
quality, increased humidity loads in the house,
and prematurely wears out the A/C equipment.
Leakage of cold supply air into the attic can
cool metal surfaces such as truss plates and
nail heads to dew point – leading to 9
condensation and material wetting.

Improvement: Reduce estimated natural infiltration from 0.4
air changes per hour (ACH) to 0.25 ACH
• Savings:
• 0.7%
• 84 kWh
• $10
• Discussion: This improvement is accomplished
by establishing a continuous air barrier around
the house which includes the slab or floor
decking, sill seal, house wrap, top plates, ceiling
drywall, and sealants at all penetrations.
Reducing infiltration has many advantages
beyond saving energy. Reducing infiltration
reduces the amount of uncontrolled air flow into the house.. This uncontrolled air which
passes through holes in the house air barrier can introduce many pollutants into the house,
either from outside, or from building cavities. These air flow paths also allow entry of
pests which are another source of allergy and asthma triggers. Building America
recommends the inclusion of a filtered and dampered outside air source introduced to the
air conditioning return, controlling outdoor air introduced to the house to provide some
fresh air into the house. This also provides a filtered, controlled air flow path for make up
10
air when exhaust fans are operated.

Improvement: Increase insulation value of floor
from R-19 to R-30
• Savings:
• 0.5%
• 61 kWh
• $7
• Discussion: This improvement was
recommended by Building America to
reach our 30% savings goal without
having to go to a higher efficiency A/C
system. Although it has a very small
payback, it has the advantage of a better
installation. When R-19 is installed in a
2X8 or 2X10 floors it is often installed so
there is an air space both above and below
the insulation, dramatically curtailing its
performance due to an increase of
convection around the insulation. If R-19
insulation is used, it should be installed
with the Kraft paper towards the crawl 11
space, and inset stapled.

Critical Detail: Air Handler Closet

Slidell
Insulation as “ceiling”
– not an air barrier

New Orleans
Closet open to attic by design
RA plenum also connected to
attic (shown in next slide)

Baton Rouge
AHU Set in Attic

Mobile (exemplary)
Drywall ceiling and walls.
Seams and penetrations 12
sealed with foil tape.

New Orleans Area HFH

*

*
AHU closet has no ceiling – so it’s Interior wall open to return air plenum
connected to attic by design; under platform (no drywall in RA plenum)
* Numerous openings connect There fore, the RA Plenum 13
closet to interior walls is connected to the attic

Mobile County Habitat AHU Closet Details

14
AHU Closet from Inside
Air Handler Closet from Outside

Mobile County Habitat AHU Closet Details

Return undersized
Switching to smaller door
And larger return
Supply Plenum Sealed to Ceiling
15

Going forward…
• Building America - High Performance Affordable Demonstration Houses:
www.baihp.org/gulfcoast
• Building America – Habitat Partnership
• Energy Star New Homes Program
– www.energystar.gov – click on “New Homes”
• Local Home Energy Raters
– http://www.natresnet.org/directory/raters.aspx
– Look for the “Volunteer Rater” emblem
• Building America Best Practices Documents
– www.buildingamerica.gov (right hand margin)
– janet@fsec.ucf.edu and david@fsec.ucf.edu
– please include “Habitat” in your subject line
16
– 321-638-1434 and 321-638-1433

Components of Ventilation System for Habitat for
Humanity Affiliates
• OA intake located in soffit near side door or porch ceiling (with step ladder access for
changing/cleaning filter)
• Heavier gauge filter back grille for OA intake (similar to those at www.registers.com)
connected to…
• Standard box/boot with collar appropriate for connecting to…
• 2” thin wall PVC pipe or 4” flex (if length exceeds 25,’ use 6” flex) Note, seal around
PVC or flex where it penetrates the ceiling of air handler closet with expanding foam,
mastic and mesh, or caulk. Connect pipe/duct to
• Manual damper with fittings in an accessible location with pipe/duct continuing to…
• Collared opening in air handler cabinet within 6” of AC coil on the return side of the coil.
This requires the mechanical contractor to cut a hole in the air handler and provide a
fitting to connect to the PVC or Flex. Seal joint at pipe/duct to collar with mastic and
fiberglass mesh.
• A motorized damper or gravity fed back draft damper may (with override control) may be
substituted for the manual damper.

17

Outdoor Ventilation Air Pipe/Duct Sizing Rationale:
• Using ASHRAE Calculation Formula for Recommended Flow:
• 7.5cfm/person + 10cfm/1000sq ft
• Estimating the number of people using the number of bedrooms plus one, we get
the following recommended flows:
• 2 Bed Room 950-1050 sq ft
• Flow=32 cfm (Approximately 30cfm)
• 3 Bed Room 1050-1150 sq ft
• Flow=41cfm (Approximately 40cfm)
• 4 Bed Room 1150-1250 sq ft
• Flow=49 cfm (Approximately 50cfm)
• The size pipe/flex recommended above will accommodate these levels of flow.
The manual
• damper may be adjusted to reduce or increase the flow if occupant desires.

18

Outside Air System Details – Filter-back Intake 20

Outside Air System Details – Filter-back Intake 21

Outside Air System Details – Intake Boot 22

Outside Air System Details – OA Duct 23

High Performance Affordable Homes

Recommended

Recommended

More Related Content

What's hot

What's hot (11)

Viewers also liked

Viewers also liked (6)

Similar to High Performance Affordable Homes

Similar to High Performance Affordable Homes (20)

Recently uploaded

Recently uploaded (20)

High Performance Affordable Homes