High Performance Affordable Homes

1,158
-1

Published on

Presentation from half day workshop on duplicating results achieved in the Department of Energy\'s Gulf Coast High Performance Affordable Housing Demonstration Project

Published in: Technology
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total Views
1,158
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
0
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

High Performance Affordable Homes

  1. 1. Building High Performance Homes Janet McIlvaine and David Beal November 20, 2008 Mobile, Alabama
  2. 2. Welcome and Introductions
  3. 3. 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
  4. 4. 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
  5. 5. 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
  6. 6. 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
  7. 7. BAIHP is estimated to save over $14,000,000/yr in 168,000+ homes G.W. Robinson Lakeland Habitat For Humanity 7
  8. 8. 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
  9. 9. G.W. Robinson Builders, Inc. – Gainesville, FL • 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
  10. 10. G.W. Robinson Builders, Inc. – Gainesville, FL • 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
  11. 11. 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
  12. 12. Lakeland Habitat for Humanity – Lakeland, FL • 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
  13. 13. Lakeland Habitat for Humanity – Lakeland, FL • 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
  14. 14. “Systems Engineering” Approach to Change Evaluation & Planning “Lessons learned” Translated into case studies, publications, & “Best Practices” documents 14
  15. 15. 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
  16. 16. 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
  17. 17. 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
  18. 18. 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…
  19. 19. Project Introduction: Building America’s Gulf Coast High Performance Affordable Housing Demonstration Project
  20. 20. 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
  21. 21. 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
  22. 22. East St. Tammany Habitat (Slidell) New Orleans Area Habitat Habitat of Greater Baton Rouge Mobile County Habitat 22
  23. 23. 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
  24. 24. 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
  25. 25. 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
  26. 26. Building Science Fundamentals
  27. 27. 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
  28. 28. 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
  29. 29. 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
  30. 30. 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
  31. 31. 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
  32. 32. 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
  33. 33. 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
  34. 34. Movement of Air, Heat, Moisture, & Water • 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
  35. 35. Movement of Air, Heat, Moisture, & Water • To have movement, need three things… – Air/heat/moisture + hole + driving force • Example: Drinking straw 35
  36. 36. 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
  37. 37. 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
  38. 38. Controlling Water, Air, and Heat 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
  39. 39. Controlling Water, Air, and Heat Principal Strategies Water: •Dry Materials •Exterior 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 39
  40. 40. All these materials are drainage planes. Which are also air barriers? House Wrap Rigid Insulation Tar Paper/Felt (sealed at edges (T&G or sealed at (Ship lapped) and seams) edges and seams) 40
  41. 41. All these materials are drainage planes. Which are also air barriers? House Wrap Rigid Insulation Tar Paper/Felt (sealed at edges (T&G or sealed at (Ship lapped) and seams) edges and seams) Is NOT an Air Barrier IS an Air Barrier IS an Air Barrier 41
  42. 42. 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
  43. 43. 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
  44. 44. 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
  45. 45. What combustion safety problem? 45
  46. 46. 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
  47. 47. Naturally Aspirated Combustion Equipment 47
  48. 48. • And now we pause for a demonstration of air flow dynamics…and combustion safety discussion 48
  49. 49. 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
  50. 50. 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
  51. 51. 80%, mid- efficiency or induced draft furnace 51
  52. 52. Direct Vent Water Heater 52
  53. 53. Sealed Combustion Condensing 90%+ AFUE Furnace 53
  54. 54. 54
  55. 55. 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
  56. 56. All Air From Outdoors. Method 1a - Vertical • Example: • Furnace = 100,000 btu/hr input • Water heater = 34,000 btu/hr input 12” max 12” max • Total btu/hr = 134,000 btu/hr 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 inches for each opening. • One within 12 inches of ceiling & one within 12 inches of the floor. Figure M703.2(b) 56
  57. 57. All Air From Outdoors. Method 1b - Horizontal Example: • Furnace = 100,000 btu/hr input • Water heater = 34,000 btu/hr input 12” max • Total btu/hr = 134,000 btu/hr 12” max 67 sq.in. input 67 sq.in. • 1 square inch per 2,000 btu/hr input required. 34k 100k 12” max 12” max • 134,000 / 4,000 = 67 square inches for each opening. • One within 12 inches of ceiling & one within 12 inches of the floor. Figure M703.2(c) 57
  58. 58. All Air From Outdoors. Method 2 • Example: • Furnace = 100,000 btu/hr input • Water heater = 34,000 btu/hr input 44.7 sq.in. ~OR~ • Total btu/hr = 134,000 btu/hr 12” max 12” max 44.7 sq.in. input • 1 square inch per 3,000 btu/hr input required. 34k 100k • 134,000 / 4,000 = 44.7 square inches for each opening. • Within 12 inches of ceiling Figure M703.2(d) 58
  59. 59. 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
  60. 60. • Air barrier and duct system holes are hard to see, but can be measured with a testing equipment. 60
  61. 61. Controlling Water, Air, and Heat Principal Strategies Water: •Dry Materials •Exterior 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 61
  62. 62. Controlling Water, Air, and Heat 62
  63. 63. Thermal Barrier • Install in a continuous, even layer • Missing insulation isn’t seen, it’s felt. • Like a hole in your coat. 63
  64. 64. 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
  65. 65. 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
  66. 66. 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
  67. 67. 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
  68. 68. Achieve Energy Star (Part 2) 1
  69. 69. 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
  70. 70. 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
  71. 71. 4
  72. 72. • 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
  73. 73. HERS Index • Comparison of projected energy use of your house to the 2004 International Energy Code Your House 98 6
  74. 74. HERS Index • Projected energy use of your house for.. – Heating, Cooling, Water Heating, Appliances, Lighting, and “Other” • Compared to 2004 IECC 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 7
  75. 75. HERS Index • Rater Needs equipment characteristics – Fuel – gas/elec – Size - capacity – Location – cond/uncond – Efficiency 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 8
  76. 76. HERS Index • Heating and Cooling Energy Use • Driven by heat gain/loss 9
  77. 77. HERS Index • Rater needs “enclosure” characteristics • Location • Dimensional characteristics • Materials/assemblies • Window characteristics • Also test results – Duct leakage – mandatory – Infiltration – optional 10
  78. 78. 11
  79. 79. 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
  80. 80. Duct Leakage • Typical leakage sites… 13
  81. 81. Duct Leakage • Typical leakage sites… – Plenum to Air Handler Connection 14
  82. 82. Duct Leakage • Typical leakage sites… Air Handler Cabinet Joints In Unconditioned Spaces Building Cavities As Ducts 15
  83. 83. Duct Leakage • Typical leakage sites… Duct System Joints in Unconditioned Spaces 16
  84. 84. 17
  85. 85. Energy Star Qualified Products • www.energystar.gov • Select “Products” – Windows, Heating/cooling, Appliances, Lighting 18
  86. 86. 19
  87. 87. Thermal Bypass Inspection Rater inspects integrity of… • Air Barrier • Thermal Barrier • Alignment of the two 20
  88. 88. Thermal Bypass Inspection • Quality of the “enclosure” • Eliminating – common “holes” in air barrier – common bypasses around insulation 21
  89. 89. 22
  90. 90. 23
  91. 91. 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
  92. 92. 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
  93. 93. Bad Insulation Installation Good Insulation Installation 26
  94. 94. 27
  95. 95. 1.3 ATTIC EAVE BAFFLES KEY POINTS Installation Criteria: • Solid baffles shall be provided at all framing bays with soffit vents to prevent wind washing at attic insulation. Tips and Best Practices: • 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
  96. 96. “Dam” for blown-in foam, cellulose, and fiberglass 29
  97. 97. 30
  98. 98. 2.1 WALL BEHIND SHOWER/TUB KEY POINTS Installation Criteria: • 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. Tips and Best Practices: • 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
  99. 99. 32
  100. 100. 4.1 DUCT SHAFT KEY POINTS Installation Criteria: • Openings to unconditioned spaces shall be sealed with solid blocking as required and any remaining gaps shall be sealed with caulk or foam. Tips and Best Practices: • 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
  101. 101. 34
  102. 102. 4.2 PIPING SHAFT/PENETRATIONS KEY POINTS Installation Criteria: • Openings to unconditioned spaces shall be sealed with solid blocking as required and any remaining gaps shall be sealed with caulk or foam. Tips and Best Practices: • 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
  103. 103. 36
  104. 104. 5.1 ATTIC ACCESS PANEL KEY POINTS Installation Criteria: • 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. Tips and Best Practices: • 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 Installation Criteria: • 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. Tips and Best Practices: • 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
  105. 105. 38
  106. 106. 5.4 RECESSED LIGHTING FIXTURES KEY POINTS Installation Criteria: • 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. Tips and Best Practices: • 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
  107. 107. 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: http://www.energystar.gov/ia/partners/bldrs_lenders_raters/dow 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: http://www.energystar.gov/ia/partners/bldrs_lenders_raters/dow 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
  108. 108. Going forward… • Building America - High Performance Affordable Demonstration Houses: www.baihp.org/gulfcoast • Building America – Habitat Partnership – www.baihp.org/habitat • 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 McIlvaine and David Beal – janet@fsec.ucf.edu and david@fsec.ucf.edu – please include “Habitat” in your subject line – 321-638-1434 and 321-638-1433 41
  109. 109. Introduction to the Gulf Coast Demonstration Homes (Part 3)
  110. 110. 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
  111. 111. 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.
  112. 112. 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
  113. 113. 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
  114. 114. 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
  115. 115. 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
  116. 116. 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
  117. 117. 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.
  118. 118. 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.
  119. 119. 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.
  120. 120. 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.
  121. 121. 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
  122. 122. Mobile County Habitat AHU Closet Details 14 AHU Closet from Inside Air Handler Closet from Outside
  123. 123. Mobile County Habitat AHU Closet Details Return undersized Switching to smaller door And larger return Supply Plenum Sealed to Ceiling 15
  124. 124. Going forward… • Building America - High Performance Affordable Demonstration Houses: www.baihp.org/gulfcoast • Building America – Habitat Partnership – www.baihp.org/habitat • 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 McIlvaine and David Beal – janet@fsec.ucf.edu and david@fsec.ucf.edu – please include “Habitat” in your subject line 16 – 321-638-1434 and 321-638-1433
  125. 125. 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
  126. 126. 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
  127. 127. 19
  128. 128. Outside Air System Details – Filter-back Intake 20
  129. 129. Outside Air System Details – Filter-back Intake 21
  130. 130. Outside Air System Details – Intake Boot 22
  131. 131. Outside Air System Details – OA Duct 23
  132. 132. 24
  133. 133. 25
  134. 134. 26
  135. 135. 27

×