auto-sealing new home leaks with aerosols -...
TRANSCRIPT
Auto-Sealing New Home Leaks with Aerosols
Curtis Harrington, PEUC Davis, Western Cooling Efficiency Center
EEBA High Performance Home Summit:October 17, 2018
Presentation Overview
»Air Sealing Benefits
»Basic Concept
»Development Timeline
»Building America Project
»Path Forward
»AeroBarrier Update
Energy Benefits of Air Sealing
»Heating and cooling is responsible for large fraction of energy use• 48% in residential
• 35% in commercial
» Infiltration is responsible for 30% of the heating and cooling load
»Better insulated envelopes increase fraction of heating & cooling associated with infiltration/ventilation
» Envelope tightness standards were fairly recently included in U.S. codes
»Cost-effective approaches to sealing envelope leakage would improve and simplify adherence to code
Health Benefits of Air Sealing
»Better control of air flow and reduced infiltration of outdoor air and outdoor pollutants (e.g. PM 2.5 or Ozone)
»Facilitates use of Mechanical Ventilation• HRV or ERV and filters• Putting HRV/ERV on leaky building doesn’t save
energy or reduce uncontrolled infiltration
Health Benefits of Air Sealing (Large Buildings)»NIST measurements of large building leakage suggest that
more air is needed for pressurization than for ventilation
»Better and more efficient air flow control in sensitive spaces
• Elimination of outdoor chemical infiltration
• Contagious disease spaces
• Clean rooms
• Laboratories
• Schools in non-compliance areas (have current CEC project on HVAC and IAQ in schools)
Health Benefits of Air Sealing (Large Buildings)»Reduce noise transfer
»Reduce smell transfer
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Sound Transfer Reduction in NYC Apartments
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Basic Concept
Seal formed between gap in foam
Blower door setup for pressurization
Building America Project Goals
Integrate aerosol sealing into building process»Determine appropriate time for applying
»Measure performance relative to conventional methods
»Determine existing sealing efforts that could be avoided
»Determine cost-effectiveness
Building America Project Team
»Project Partners: • Center for Energy and Environment • Building Knowledge Inc.• University of Minnesota’s Cold Climate Housing
Program• Aeroseal LLC
»Builders:• Two in California• Two in Minnesota
Building America Project ApproachHouse
Leakage Assessment
• Review existing sealing practices
• Aerosol sealing demonstration
Develop Two Sealing
Options
• Meet with builder to go over options
• Pick two promising approaches
Perform Aerosol Sealing
• Seal at least two homes under each option
• Evaluate impact relative to baseline
Refine Sealing Options
• Refine most promising option
Perform Aerosol Sealing
• Seal 3-4 homes under refined option
Building America Interim Results (CA)»California Builder #1
»Homes designed with sealed attics
»Using open-cell spray foam• Under roof deck
• At rim joist and other mechanical penetrations
»Fiberglass/mineral wool in wall cavity
»HRV integrated into central air handler
»Target leakage of 800 CFM50 (2.1-2.4 ACH50)
Conventional Sealing
Can foam at seams where wood is joined
Can foam and gasket at sill plate
Foam gasket to seal drywall to top plate
Sealing Options
»Sealing options• Option 1: After open-cell spray foam
• Option 2: Before spray foam insulation
»Advantage of sealing before drywall• Addresses outer wall surface
• Seals less prone to damage in wall cavity
• Easier aerosol distribution
Option 1: After Foam
Foam at roof deck
Foam at rim joist
Results Sealing After Foam
Stage/Option Lot PlanFloor Area
(ft2)Volume
(ft3)
Pre-Seal Post-Seal
CFM50 ACH50 CFM50 ACH50 % ReductionDemo 1 After Foam 7 3 2569 23121 1690 4.39 429 1.11 75%Demo 2 After Foam 8 1 2032 22215 1286 3.47 351 0.95 73%
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0 20 40 60 80 100
Le
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ag
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cfm
at
50
Pa
)
Elapsed Minutes
Demo 1 Demo 2
Example Seals After Foam
Seals formed under trusses Seal formed at corner of wall
assembly
Option 2: Before Foam
Exposed roof deck
Rim joist penetrations
Option 2 Pre sealing work
»Large penetrations needed to be sealed prior to aerosol sealing
»Time/materials for pre-sealing was tracked
Prepare for unexpected!
Pre-Sealing Time/MaterialsSealing Penetrations Sealing Gap at Eaves
Stage/Option
Time for Manual Sealing
(person-hours) Cans of Foam Used
Time for Manual Sealing
(person-hours) Cans of Foam Used
Before Foam 1.5 3 1.5 4
Before Foam 4.5 6 1 4
*Note: Pre-sealing work performed by inexperienced staff
Option 2 Results
After Foam
CFM50 ACH50 % Reduction
483 1.25 6%
352 1.06 4%
Stage/Option Lot PlanFloor Area
(ft2)Volume
(ft3)
Pre-Seal Post-Seal
CFM50 ACH50 CFM50 ACH50 % ReductionDemo 1 Before Foam 23 3 2569 23121 5836 15.14 828 2.15 86%Demo 2 Before Foam 24 2 2223 20007 3005 9.01 477 1.43 84%
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0 40 80 120 160 200
Le
ak
ag
e (
cfm
at
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Pa
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Elapsed Minutes
Demo 1 Demo 2
Option 2 Example Seals
CA Builder #1 Results Summary
»39% tighter than two control houses
»55% tighter than Zero Energy Ready requirement of 2.5 ACH50 0
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Demo 1 Demo 2 Demo 1 Demo 2 Baseline Baseline
AC
H5
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Pre-Seal Post-Seal After Foam End-Const
After Foam Before Foam
Avg. 1.1 ACH50 Avg. 1.8 ACH50
Further Testing In Sealed Attics
»California Builder #2
»Homes designed with sealed attics
»Using netting and blown-in cellulose insulation at roof deck
»Fiberglass/mineral wool in wall cavity
»HRV integrated into central air handler
Conventional Sealing
Gasketed light fixtures
Can foam in expansion joint at roof deck and HVAC penetrations
Foam gasket at sill plate
CA Builder #2 – Before Insulation
Challenges
Air barrier installed to block garage attic from house attic
Gap between exterior foam and roof
CA Builder #2 Results Summary
»41% tighter than two control houses (before drywall)
»Final end of construction testing planned this week
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Before Blow-InInsulation
Before Blow-InInsulation
Baseline Baseline Baseline
En
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(A
CH
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)
Pre-Seal Post-Seal End-Const
Avg. 3.0 ACH50Avg. 5.1 ACH50
Testing In Vented Attics
»California Builder #1
»Vented attic with blow-in insulation on ceiling
»Fiberglass/mineral wool in wall cavity
»HRV integrated into central air handler
Sealing Strategy
»Sealed after drywall, mud and tape
»Temporarily covered fire sprinklers
Conventional Sealing
Sealing Results»80% reduction in leakage
»90 minutes of sealant injection
»65% below Title 24 code
1.69
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Demo 1 Demo 2
En
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Pre-Seal Post-Seal End-Construction 0
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0 20 40 60 80 100
Le
ak
ag
e (
cfm
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Pa
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Elapsed Minutes
Sealing Profile for Demo 1
Example Seals
Building America Interim Results (MN)»Minnesota Builder #1
»Homes designed with ventilated attics
»Closed-cell spray foam at rim joist
» Interior poly wrap
»Fiberglass/mineral wool in wall cavity
»ERV integrated into central air handler
Conventional Sealing
Caulk at seams where wood is joined
Can foam at wire penetrations
Caulk at sill plate
Proposed Sealing Options
»Option 1: • Seal home after spray foam at rim joist
• Reinforced poly at ceiling-attic interface
• Maintain conventional sealing
»Option 2 (Ultimately not implemented): • Seal home after spray foam at rim joist
• Reinforced poly at ceiling-attic interface
• Do not install: Airtight electrical boxes
Interior poly
Sealing Results
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0 50 100 150 200 250 300 350
Le
ak
ag
e (
cfm
at
50
Pa
)
Elapsed Minutes
Reinforced poly failed
Example Seals
Seal formed between studs
Seals formed at wire penetrations
Seal formed at
electrical box
Seals formed at
plumbing penetrations
MN Builder #1 Results Summary
» 41% tighter than two control houses
» 56% tighter than Zero Energy Ready requirement of 2.0 ACH50
0.0
0.5
1.0
1.5
2.0
2.5
3.0
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4.0
4.5
5.0
#2 Demo #1 Demo Blaine Eagan Plymouth Lakeville ControlLakeville
ControlEagan
AC
H5
0
Pre-Seal Post-Seal End-Const
50% 84% 72% 82% 46% 66%
% Reduction of Sealing
Batt Insulation in Walls
IECC Code zones 3 - 8
Passive House
garage area converted to sales office
0.88 average
Final Takeaways
»Aerosol sealing was very effective• Reduced air leakage by 75-80%
• Achieved leakage rates well below codes
»Only 1-3 hours of total injection time
»Can replace many conventional sealing tasks
»Assures leakage targets are met• Provides verification
Project Path Forward
»Complete testing with vented attics
»Complete end of construction tests
»Determine cost effectiveness:• Gather cost data from builders• Compare costs and performance to conventional
sealing approaches
Research Path Forward
»Application in commercial buildings• Completed a project for DoD on non-res retrofits• Commercial buildings present challenges
Roof-to-wall connection
Supplemental manual sealing sometimes required
»Application in existing homes• Existing homes are leakier• Apply at time of tenant change