Guide to Energy Efficient Homes in Louisiana Louisiana Department of Natural Resources Technology Assessment Division Scott A. Angelle, Secretary T. Michael French, Director Paula Ridgeway, Manager Principal Authors James E. Davidson, Sr., CSI Jerry Heinberg, AIA, NCARB Billy Williamson, EIT, EMIT Project Manager David McGee, PE, CEM Technical Review Howard Hershberg, AIA David McGee, PE, CEM Graphics and Layout James E. Davidson, Sr., CSI Jerry Heinberg, AIA, NCARB Billy Williamson, EIT, EMIT Contact For more information on any of the energy services mentioned in this guide, please contact: Technology Assessment Division: Main Number: 225-342-1399 Toll-free: 1-800-836-9589 Fax: 225-342-1397 E-mail: [email protected] Website: http://www.dnr.state.la.us/energy The contents of this manual are offered as guidance. The Louisiana Department of Natural Resources, nor any of its employees, nor any of its contractors, subcontractors, or their employees, and all technical sources referenced in this manual do not (a) make any warranty or representation, express or implied, with respect to the accuracy, completeness, or usefulness of the information contained in this report, or that the use of any information, apparatus, method or process disclosed in this report may not infringe privately owned rights; (b) assume any liabilities with respect to the use of, or for damages resulting from the use of any information, apparatus, method, or process disclosed in this report. This report does not reflect official views or policy of the above mentioned institutions. Mention of trade names or commercial products does not constitute endorsement or recommendation for use. This page left intentionally blank. Table of Contents 1. Site Planning 1 Changing Times – Professional Advice 1 Surveys 1 Location and Size 2 Drainage 2 Earthwork 2 Views and Access 3 Understanding Solar Position 3 Natural Cooling 4 Natural Ventilation 6 Landscaping and Trees 10 2. The House as a System 13 Concepts 14 Systems in a Home 21 Systems are Interdependent 29 3. Energy Efficient Features 31 Achieving Energy Efficiency 31 Appendix – Energy Star Homes Technical Resources 47 4. Air Leakage Sealing – Materials and Techniques 53 Air Leakage Driving Forces 54 Materials 58 Seal Penetrations and Bypasses 58 Airtight Drywall Method 64 Housewrap Air Barriers 67 5. Insulation Materials and Techniques 73 Insulation Materials 73 Foundation Insulation 77 Basement Wall Insulation 78 Framed Floor Insulation 81 Wall Construction 85 Ceilings and Roofs 98 6. Windows and Doors 109 Windows 109 Doors 121 Overall Window and Door Recommendations 122 Table of Contents i 7. Heating, Ventilation, and Air Conditioning 123 Types of HVAC Systems 123 Air Conditioning Equipment 126 Heating Systems 129 Ventilation and Indoor Air Quality 137 Overall HVAC Recommendations 142 8. Duct Design and Sealing 143 Duct Materials 143 The Problem of Duct Leakage 144 Duct Design 151 Conclusion 157 9. Water Heating, Appliances and Lighting 159 Water Heating 159 Appliances 165 Lighting 168 10. Energy Efficient Roofing 173 The Roof Structure (A Good Foundation!) 173 Green Roofs 184 11. Fingertip Facts 187 Abbreviations 187 Energy and Fuel Data 187 Average Daily Solar Radiation 187 Insulating Values 188 HVAC Equipment Efficiencies 189 Climatic Data for Louisiana 189 ii Table of Figures 1. Site Planning Figure 1-1 Solar Path Chart 4 Figure 1-2 Wind Roses Summer and Winter 5 Figure 1-3 Natural Ventilation Design Strategies 6 Figure 1-4 Stack Effect 7 Figure 1-5 Overhang Types 7 Figure 1-6 Site Planning 8 Figure 1-7 Site Planning 9 2. The House as a System Figure 2-1 Home Losing Heat through Conduction in Winter 14 Figure 2-2 Convection in the Home 15 Figure 2-3 Radiation Entering House 15 Figure 2-4 Air Quality Problems from “Fresh” Air 16 Figure 2-5 Thermal Boundaries 17 Figure 2-6 Conditions for Condensation 17 Figure 2-7 Psychometric Chart 19 Figure 2-8 Winter Dew Point Temperature Inside Walls 19 Figure 2-9 Summer Condensation in Walls 20 Figure 2-10 Relative Humidity Ranges 21 Figure 2-11 Bulk Moisture Transport 23 Figure 2-12 Drainage Plane 24 Figure 2-13 Capillary Action 25 Figure 2-14 Typical Water Vapor Transport 26 Figure 2-15 Drying to the Interior 27 3. Energy Efficient Features Figure 3-1 International Residential Code (2006) Climate Zone Map 33 Figure 3-2 Envelope Construction Ideas 34 Figure 3-3 Sealing Holes in Framing 34 Figure 3-4 More Sealing Techniques 35 Figure 3-5 Typical Insulated Concrete Forms (ICF) 44 Figure 3-6 Typical Structural Insulated Panel 45 Table of Figures iii 4. Air Leakage Sealing – Materials and Techniques Figure 4-1 Creating a Pressure Boundary 54 Figure 4-2 Wind Driven Infiltration 55 Figure 4-3 The Stack Effect 55 Figure 4-4 Mechanical System Driven Infiltration 56 Figure 4-5 Blower Door 57 Figure 4-6 Home Blower Door Test 58 Figure 4-7 Air Leakage through Bypass 59 Figure 4-8 Typical Home Air Leakage Sites 60 Figure 4-9 Sealing Bypasses 62 Figure 4-10 Sealing More Bypasses 63 Figure 4-11 Airtight Drywall Method Air Barrier 64 Figure 4-12 Creating an Air Barrier Between Floors 66 Figure 4-13 Housewrap – Window Connection 68 Figure 4-14 Recommended Housewrap Installation Process & Procedure 69 Figure 4-15 Sealing Sheathing as Exterior Air Barrier 70 5. Insulation Materials and Techniques Figure 5-1 Insulating the Building Envelope Recommended Insulation Values 73 Figure 5-2 Insulating Concrete Block Cores 77 Figure 5-3 Relative Humidity (RH) and Foundation Vents 78 Figure 5-4 Interior Foam Wall Insulation 79 Figure 5-5 Interior Framed Wall 79 Figure 5-6 Insulated Concrete Form Wall Systems 80 Figure 5-7 Insulated Wood Framed Floors 81 Figure 5-8 Insulated Floor over Pier Foundation 82 Figure 5-9 Insulated, Sealed Crawlspace Walls 83 Figure 5-10 Floor Insulation Details 84 Figure 5-11 Let-in Bracing 86 Figure 5-12 Advanced Framing Insulation Details 87 Figure 5-13 Standard Framing versus Advanced Framing 88 Figure 5-14 Insulating Walls with Batts 89 Figure 5-15 Blown Sidewall Insulation Options 90 Figure 5-16 Spray Foam Insulation 91 Figure 5-17 Structural Insulated Panels (SIP) 92 Figure 5-18 Structural Insulated Panels Construction 93 Figure 5-19 Foam Sheathing Keeps Walls Warmer 95 Figure 5-20 Average Wall R-Value 97 Figure 5-21 Ridge and Soffit Vents 98 Figure 5-22 Pressure Problems Due to Powered Attic Ventilators 99 Figure 5-23 Attic Blocking Requirements 101 Figure 5-24 Full Width Batts 102 Figure 5-25 Insulating under Attic Floors 102 Figure 5-26 Insulation Options for Eaves 104 Figure 5-27Airtigt, IC-rated Recessed Lamps 105 Figure 5-28 Cathedral Ceiling Insulation Options 106 Figure 5-29 Cathedral Ceiling – Exterior Roof Insulation 107 iv 6. Windows and Doors Figure 6-1 Window Anatomy 110 Figure 6-2 Winter Heat Loss in a Typical Double-glazed Window 111 Figure 6-3 Summer Heat Gain in a Typical Double-glazed, Low-e Window 111 Figure 6-4 Relative Intensity of the Solar Spectrum 112 Figure 6-5 Metal Window with Thermal Break 115 Figure 6-6 Low-e, Gas-filled Windows 116 Figure 6-7 NFRC Label 117 Figure 6-8 Inside Window Temperatures in Cold Weather 118 Figure 6-9 Composition of Solar Heat Gain into Home 118 Figure 6-10 Guidelines for Overhangs 119 7. Heating, Ventilation, and Air Conditioning Figure 7-1 Components of Forced-Air Systems 123 Figure 7-2 Automatic Zoned System with Dampered Bypass Duct 126 Figure 7-3 Air Conditioning with the Vapor Compression Cycle 127 Figure 7-4 Air Source Heat Pump 130 Figure 7-5 Sealed Mechanical Room Design for Non-direct Vent Furnace 132 Figure 7-6 Integrated Space and Water Heating System 134 Figure 7-7 Efficient Wood Heater Design 136 Figure 7-8 Direct Vent Heaters 137 Figure 7-9 Ventilation with Spot Fans 138 Figure 7-10 Whole House Ventilation System 139 Figure 7-11 Heat Recovery Ventilation (HRV) System 141 8. Duct Design and Sealing Figure 8-1 Types of Ductwork 143 Figure 8-2 Efficiency Losses Due to Attic Return Leaks 145 Figure 8-3 Sealing Flex-duct Collar with Mastic 146 Figure 8-4 Disconnected Ducts are High Priorities 148 Figure 8-5 Duct Test on Return Grille 149 Figure 8-6 Duct Leaks in Inside Spaces 149 Figure 8-7 Seal All Leaks in Air Handling Unit 150 Figure 8-8 Shelf-Mounted Systems without Returns 150 Figure 8-9 Seal All Leaky Takeoffs 151 Figure 8-10 Sealing Leaky Boots 151 Figure 8-11 Comparison of Air Flow in Different 6-inch Ducts 152 Figure 8-12 Jump Duct 154 Figure 8-13 Transfer Grills – Over Doors 155 Figure 8-14 Transfer Grills – In Wall 156 Figure 8-15 Louvered Passage Doors 156 Table of Figures v 9. Water Heating, Appliances and Lighting Figure 9-1 Typical Breakdown of Hot Water Use 160 Figure 9-2 Insulating Jackets for Electric and Gas Water Heaters 161 Figure 9-3 Heat Pump Water Heaters 162 Figure 9-4 Active Solar Water Heating Systems 163 Figure 9-5 Batch Solar Water Heating Systems 164 Figure 9-6 EnergyGuide Label 166 Figure 9-7 Efficacy of Different Lighting Types 169 10. Energy Efficient Roofing Figure 10-1 Color Standard Cool Roof Color Materials 176 Figure 10-2 Laminated Shingles 178 Figure 10-3 Natural Slate Tiles 178 Figure 10-4 Concrete Tiles 179 Figure 10-5 Rubber Shingles 179 Figure 10-6 Landscaped “Green Roof” 185 vi Table of Tables 1. Site Planning Table 1-1 Shading Design Strategies 11 2.