Residential Energy Code Compliance

Residential Energy Code Compliance
IRC 2000 IECC 2000/2001/2003 U.S. Department of Energy Building Energy Codes Program 1

The Family of I-Codes The 2000/2001 ICC IECC contains energy provisions for both residential and commercial buildings. The IECC is one of the International Codes. The IECC enables effective use of energy in new building construction by regulating: Building Envelope - focuses on air sealing, minimum insulation levels, and efficient glazing Mechanical Systems - addresses equipment efficiency, HVAC controls and heating and cooling distribution. Electrical Systems - focuses on interior and exterior lighting wattage limits and controls for efficient lighting usage. Service Water Heating Systems - addresses water heating efficiency and hot water distribution. 2

Structure of the IRC Building Envelope IRC Chapter 8 IRC Chapter 3
Requirements for Insulation IRC Chapter 4 Foundation waterproofing and dampproofing Foundation drainage Foundation venting IRC Chapter 5 Shallow frost foundations IRC Chapter 7 Weather resistant coverings for walls IRC Chapter 8 Weather resistant coverings for roof assemblies Mechanical System IRC Chapter 14 Heating and cooling sizing calculations and sizing requirements 3

Relationship Between IRC and IECC
Chapter 11“Sets forth energy-efficiency related requirements for the design and construction of buildings…..” Section N Residential Buildings, Detached One- and Two Family References IECC for buildings > 15% gross wall area Section N Residential Buildings, Townhouses References IECC for buildings > 25% gross wall area Section N1103 Mechanical System References IECC Section for HVAC Efficiency Section N1104 Water Heating Efficiency References IECC Section for water heating efficiency Chapter 11 of the International Residential Code (IRC) is identical to Chapter 6 of the IECC. The Chapter is limited in usage to one- and two-family residential (Type A-1) construction with 15% or less glass to wall area and to townhomes (Type A-2) with less than or equal to 25 % glass to wall area. The IRC references the IECC for residential applications that go above these percentages. Chapter 11 of the IRC references sections within the IECC for HVAC equipment efficiency and also water heater efficiency. If there are any questions as to these requirements the following tables can be referenced: Table Minimum Equipment Performance (HVAC) Table Minimum Performance of Water-Heating Equipment 4

Residential Chapters Structure of the IECC
Chapter 1 Administrative & Enforcement Chapter 2 Definitions Chapter 3 Design Conditions Chapter 4 Residential - Systems Analysis Chapter 5 Residential - Component Performance Chapter 6 Simplified Prescriptive Requirements Chapter 7 ASHRAE Energy Code Reference Chapter 8 Design by Acceptable Practice for Commercial Buildings Chapter 9 Referenced Standards Residential Chapters 5

Presentation Reference
Requirement covered by material is highlighted in red. Mandatory requirements such as moisture and infiltration control must usually be met regardless of location or design. Specific requirements such as insulation levels are based on the project location (HDD) and window wall ratio. Code year covered in current presentation. 2000/ 2001/ 2003 IECC Mandatory Requirements Section 501 Moisture Lighting Infiltration SHGC Envelope Mechanical 6 Code Section # Requirements are outlined in Chapter 5 (Section 502.1) of the IECC. Requirements can be met by the approaches in Chapter 5 or the simplified tables of Chapter 6. This presentation covers 2000/2001/2003 IECC Residential Requirements – New 2001/2003 requirements are listed in red. 6

Residential Compliance Outline
Current Presentation Overview of Residential Energy Codes Energy Code Compliance Options Energy Code Requirements Mandatory Requirements Specific Requirements Building Science Concepts Systems Design and the Code Compliance Using REScheck (Case Study) Basic Code Compliance Presentation Building Science/ Code Compliance Presentation Case Study Presentation For additional training materials see 7

IECC Code Compliance Options
Prescriptive Total Building Trade Off Energy Analysis Individual Component Basis Total Building UA Energy Analysis Chapter 4 Not covered in this presentation. Acceptable Practice Prescriptive Specification Simplified Prescriptive Chapter 6 8

Code Compliance Tools Prescriptive . Total Building Trade Off
Energy Analysis Prescriptive Package Worksheet (manual) Prescriptive Tables Trade-off Worksheet (manual) Software REMdesign REMrate EnergyGauge REScheck Software (Web-based & Desktop) REScheck Package Generator (Web-based) Not covered in this presentation. 9

Chapter 4 Residential – Systems Analysis
Requires a computer program Chapter 4 spells out additional essential types of input values (not applicable in REScheck), such as: House tightness (measured by test for “Final Rating;” projected for “From Plans Rating”) Window solar access and orientation evaluated Duct tightness evaluated Water heating (appliance Energy Factor) Thermal mass present Under the systems analysis approach, a building designed in accordance with Chapter 4 (the “Proposed design”) will comply with the code if the calculated annual energy consumption is not greater than a similar building (the “Standard design”) designed in accordance with Chapter 5. Chapter 5 offers a prescriptive path to code compliance that does not require the “annual energy analysis.” The Proposed design uses the same energy sources, floor area, geometry, design conditions, occupancy, climate data, and usage schedule as the Standard design. Some energy-conserving strategies to improve the performance of the Proposed design include exterior shading of windows, passive solar design, thermal mass heat storage, improved thermal envelope, improved duct systems, reduced air infiltration, and high-efficiency heating, cooling, and water heating equipment. The comparison is expressed as Btu input per square foot of gross floor area per year, where 1 kWh = 3,413 Btu. 10

BECP Code Compliance Tools
Prescriptive Approach Trade-off Approach Simple, fast and easy Generally most stringent Requires minimum input Based on climate and WWR Uses a prototype building Trade-off between components Provides design flexibility Requires area & U/R-factors Uses UA calculation (REScheck) & regression equations (COMcheck) Residential REScheck Prescriptive Tables & Printed Guides REScheck Web Package Generator REScheck desktop software for Windows and Mac with AreaCalc tool REScheck-Web software Web Based Tools Commercial COMcheck-EZ Prescriptive Tables / Printed Guides COMcheck Web Package Generator COMcheck-EZ desktop software for Windows COMcheck-Web software Web Based Tools 11

Scope Detached one and two–family dwellings
R-2 (A-1) and R-4 (A-2) Residential Buildings containing 3 or more dwelling units where the occupants are permanent in nature and are 3 stories or less in height Additions, including Sunrooms R-2 and R-4 replaced A-1 and A-2 in 2003 IECC Sunroom requirements were added in 2001 and 2003 IECC Section 101 12

Exceptions Very low energy use buildings (<3.4 Btu/h-ft2 or 1 watt/ft2) Buildings (or portions of) that are neither heated nor cooled Buildings designated as historic (Section ) Very low energy use building This includes heating, cooling, lighting and water heating Have participants review Section An unconditioned warehouse is an example of an unconditioned space Buildings designated as historic National/state/local historical register Some jurisdictions may still require additions to these structures to comply with the energy code. Section 13

Changes to Occupancy Alterations to existing spaces
Applies to only portions of the systems being altered Applies if alteration increases energy use Alterations must meet the requirements applying to the altered component New systems in the alterations must comply Alterations to an existing space can be changing an unconditioned space into a conditioned space such as finishing out an unconditioned basement. Alterations to the energy using systems may result due to a change of occupancy. For example, more lighting might be required for a retail store that is moving into an existing office space, resulting in an increased lighting load on the space. In most cases, existing envelope, lighting, and mechanical systems and components set the requirements for alterations. For example, envelope alterations comply if the overall performance of the envelope is not degraded. Similarly, lighting alterations comply if the building’s overall connected lighting load does not increase. Mechanical alterations are governed primarily by the requirements for each altered component. Section 14

Mixed Use Buildings Minor occupancy Office <10% of floor area
Treat as major occupancy Hotel/motel and commercial occupancies Treat as different commercial occupancies Mixed residential and commercial occupancies Treat the residential occupancy under the applicable residential code Treat the commercial occupancy under the commercial code Office Residence Apartments Mixed residential and commercial occurs when a building has three or fewer stories and contains both residential and commercial occupants, with the minor occupancy type taking up more than 10 percent of the building’s conditioned floor area. The residential and commercial occupancies fall under two different scopes. Thus, two compliance submittals must be prepared using the appropriate calculations and forms from the respective codes for each. Buildings > 4 stories are considered commercial buildings Restaurant Section 15

Building Envelope The intent of the energy code is to regulate the design of the building envelope to enable the effective use of energy. The Building Envelope separates conditioned space from unconditioned space or the outdoors. Conditioned space attic What comprises the bldg. envelope? Bldg. Envelope separates conditioned space from unconditioned space or outdoor. Conditioned Space is the area that is being heated and cooled. 16

Building Envelope Defining the area of the building envelope of conditioned space. 17

Building Envelope Requirements
1) Mandatory Requirements: Moisture Control Recessed Cans Infiltration Control Solar Heat Gain Coefficient 2) Climate Specific Requirements: Foundations Basements Slabs Crawlspaces Above Grade Walls Skylights, Windows, and Doors Roofs There are mandatory envelope requirements (design must meet these requirements regardless of location) which include moisture control and infiltration control. Other envelope requirements such as insulation values and window efficiency are based on the project location, window wall ratio etc. Section 502.1 18

Moisture Control Why a Vapor Retarder?
Vapor travels from high pressure to low pressure. Moisture-laden air is literally "pushed" through penetrations in the building envelope. The moisture could damage the insulation and even the framing members, but a continuous vapor barrier helps prevent this from happening. Section 19

Vapor Retarders – Code Requirements
Basic Requirements Install on “warm-in-winter side” of insulation Use in unvented framed walls, floors, and ceilings Must have perm rating of ≤ 1.0 per Procedure A of ASTM E 96 Nonvented areas are framed cavities without vents or other openings to allow for free air movement. Normally the “warm-in-winter” side of the insulation will be the inside of the building. The vapor retarder will be placed between the insulation and the sheetrock facing the interior of the building. Typical vapor retarders include the craft facing on fiberglass batt insulation and polyethelene sheet. ASTM E is a testing method referenced in the IECC. Section 20

Vapor Retarder - Exceptions
Climate Zones 1 through 7 (IECC Chapter 3) In construction where moisture or its freezing won’t damage materials If other approved means to avoid condensation are provided Vapor retarders are not required where moisture or its freezing will not damage materials. Climate Zones 1 through 7 are exempt from this requirement. Each state is divided up into a series of climate zones. The Climate Zone maps are located in Chapter 3 of the IECC. States with no vapor retarder requirements (IECC 2001) Section 21

Vapor Retarders - Options
Kraft-faced Vapor Retarder Poly Vapor Retarder Polyethylene sheathing over unfaced fiberglass batt insulation is commonly used in wall construction. The polyethylene sheathing meets the one-perm requirement. This installation is not recommended as moisture trapped in the building cavity cannot dry out through the poly sheathing. Section 22

Vapor Retarders - Examples
Vapor retarder – wall Vapor retarder -- soffit Section 23

Recessed Lighting Fixtures
Type IC rated, with no penetrations between the inside of the recessed fixture and ceiling cavity (sealed and caulked) Type IC or non-IC rated, installed inside a sealed box of ½" gypsum wallboard or other assembly manufactured for this purpose Type IC rated, in accordance with ASTM E 283 to be an “Air-Tight” enclosure When installed in the building envelope, recessed lighting fixtures shall meet one of these requirements. IC means “insulated ceiling.” Another designation label you might encounter is Air-Lok. The Type IC or non IC rated installed inside the sealed box while maintaining required clearance of not less the .5 inch from combustible materials and not less than 3 inches from insulation material. Type IC rated in accordance with ASTME E283 admitting no more than 2.0 cfm of air movement from the conditioned space to the ceiling cavity. Section 24

Recessed Lighting Fixtures
Typical “rough-in” for recessed light fixtures. Section 25

- + + - What is Infiltration? Wind Stack
Infiltration is the unwanted air movement through a building and is caused by a pressure difference (air moves from high pressure to a lower pressure) Airflow Wind + - Neutral Pressure Plane Stack + - Infiltration is the unwanted air movement through a building and is caused by a pressure difference (air moves from high pressure to a lower pressure). Wind can cause air movement through a house as a the windward side is considered a high pressure side and pushes air through the house to the low pressure side of the building (the leeward side). Warm air rising in a building can cause air infiltration and is referred to as the stack effect. As warm air raises it pushes against the inside of walls and roof/ceiling assembly of a two-story home. The warm air may leave the home through holes or openings in the building. As this air leaves, it creates a negative pressure in the lower portion of the home and pulls in cooler outdoor air through cracks and penetrations in the building. Section 26

Areas for Air Leakage Windows and doors Between sole plates
Floors and exterior wall panels Plumbing Electrical Service access doors or hatches There is no specific code language that precisely dictates how a leak should be seal or how to judge the quality of a seal. There are several places where air leakage can occur: Exterior joints around window and door frames Between wall sole plates, floors, and exterior wall panels Openings for plumbing, electrical, refrigerant and gas lines in exterior walls, floors and roofs Openings in the attic floor such as where ceiling panels meet interior and exterior walls and masonry fireplaces Service and access doors or hatches Section 27

Air Leakage Control Building envelope
Sealed with caulking materials or Closed with gasketing systems Joints and seams sealed or taped or covered with a moisture vapor-permeable wrapping material Sealing materials spanning joints between construction materials shall allow for expansion and contraction of the construction materials. Section 28

Windows - SHGC Solar Heat Gain Coefficient
Requirements can be dependent on projection factor National Fenestration Rating Council (NFRC) tested Default SHGC range diagrams SHGC = SC x .87 Solar Heat Gain Coefficient SHGC is a measure of how much solar gain is transmitted through the window by solar radiation The lower the SHGC value of a window the less sunlight and heat can pass through the glazing. In locations with heating degree days (HDD) less than 3,500 the combined solar heat gain coefficient (the area weighted average) of all glazed fenestration products (including the effects of any permanents exterior solar shading devices) in the building shall not exceed .40. The SHGC requirement is affected by overhangs on a building. The code uses the term projection factor to determine how well the overhang shades the glazing. The PF is calculated by measuring the distance from the window to the farthest-most edge of the overhang and dividing that by the distance from the bottom of the window to the lowest point of the overhang The greater the PF the better the window is shaded. The better the window is shaded the less important the solar heat rejection qualities of the window. So a window with a higher SHGC value can be used to comply with the code. If overhangs are shown on the building plans, ensure that they have been installed according to the design. Section 29

Locations with SHGC Requirements
Areas/locations with a heating degree days (HDD) of less than 3500 hdd Section 30

SHGC DEFAULT TABLE FOR FENESTRATION
Product Description Single Glazed Double Glazed Clear Bronze Green Gray Clear + Clear Bronze + Clear Green + Clear Gray + Clear Metal Frames Operable Fixed 0.75 0.78 0.64 0.67 0.62 0.65 0.61 0.66 0.68 0.55 0.57 0.53 0.52 0.54 Nonmetal Frames Operable Fixed 0.63 0.46 0.45 0.44 A good point to note, none of the default values in this table meet the .40 SHGC mandatory requirement for areas in 3500 hdd or less Section 31

Specific Requirements
1) Mandatory Requirements: Moisture Control Recessed Cans Infiltration Control Solar Heat Gain Coefficient 2) Specific Requirements: Foundations Basements Slabs Crawlspaces Above Grade Walls Skylights, Windows, and Doors Roofs With specific requirements, there are several variables in determining which approach you use to show compliance Section 502.2 32

Envelope Requirement Compliance Options
Section Heating and Cooling Criteria Individual Component Basis Total Building Performance Acceptable Practice Prescriptive Specification Uo Graphs Uo Tables from Appendix Chap. 5 Prescriptive Tables REScheck Software Most Flexible Approach Section Thermal Performance Criteria These are the different variables for compliance. REScheck also performs a simple hvac efficiency trade off towards the building envelope. Simplified Prescriptive Tables Use if WWR < 15% for S.F., < 25% for M.F. Chap. 6 Prescriptive Tables 33

R-Values Thermal resistance to heat flow
The larger the number the better The R-value of layers in an assembly can be added together R-values are better understood than U-values. The bigger the number the better. 34

U-Factors The amount of heat in Btu (British thermal units) that flows each hour through one square foot, when there is a 1ºF temperature difference across the surface The smaller the number the better An understanding of U-factors is critical to compliance and enforcement of the building envelope requirements. 35

Floors over Unconditioned Space
Crawlspace is vented when the floor above is insulated. Meet or exceed R-value requirements. Section 502.2/ 602.1 36

Supported Floor Insulation
Support insulation in floor cavity Section 502.2/ 602.1 37

Floors over Outside Air
Floors over outside air must meet ceiling R-value requirements Section 502.2/ 602.1 38

Crawlspace Wall Insulation
When crawlspace walls are insulated, foundation vents are not required. Space should be mechanically vented or conditioned. Installing insulation on the inside surface of the foundation stemwall is common practice in many cold locations in the country. This practice eliminates the need to install insulation in the raised floor over the crawlspace. There are a few criteria that must be met in order to use this insulation method: The crawlspace may not have ventilation openings that communicate directly with outside air The crawlspace must be mechanically ventilated or supplied with conditioned air The crawlspace floor must be covered with an approved vapor retarder material. The IRC allows the construction of unventilated crawlspaces. To meet the requirements the crawlspace walls must be insulated to the R-value specified in the energy code. The crawlspace must either be provided with conditioned air or with mechanical ventilation. The code does not specify the quantity of conditioned air to supply the crawlspace. If mechanical ventilation is selected, the crawlspace must be ventilated at 1 CFM per 50 square feet. The ground surface must also be covered with an approved vapor retarder material. To eliminate moisture from the crawlspace the sill plate and perimeter joist must be sealed. Also, while not a code requirement, all joints in the vapor retarder should be overlapped and taped. This includes the connection between the vapor retarder and crawlspace wall. The code requires the crawl space wall insulation to extend from the top of the wall to the inside finished grade. If the inside grade is less than 12 inches (305 mm) below the outside finished grade or the vertical wall insulation stops less than 12 Section 502.2/ 602.1 39

Vented & Unvented Crawlspaces
Vented Crawlspace Requirements: The raised floor over the crawlspace must be insulated to the code R-value requirements for floors (varies by location). A vapor retarder may be required as part of the floor assembly (varies by location). Ventilation openings must exist that are equal to at least 1 square foot for each 150 square feet of crawlspace area and be placed to provide cross-flow (IRC 408.1, may be less if ground vapor retarder is installed). Unconditioned crawlspace ducts must be sealed and meet R-value insulation requirements (IECC Table ) - usually R-5. Unvented Crawlspace Requirements: The crawlspace ground surface must be covered with an approved vapor retarder (e.g., plastic sheeting). Crawlspace walls must be insulated to the R-value requirements specific for crawlspace walls (IECC , , and Table 602.1). Crawlspace wall insulation must extend from the top of the wall to the inside finished grade. Crawlspaces must be mechanically vented (1 cfm per 50 square feet) or conditioned (heated and cooled as part of the building envelope). Section 502.2/ 602.1 40

Slab Edge Insulation Proposed R-value must meet or exceed
Downward from top of slab a minimum of 24” (< 6000 HDD), 48” (> 6000 HDD) Downward to at least the bottom of the slab and then horizontally – 24” (< 6000 HDD), 48” (> 6000 HDD) Slab-edge insulation may be installed vertically or horizontally on the inside or outside of foundation walls. If installed vertically, it must extend downward from the top of the slab to the top of the footing. If installed horizontally, it must cover the slab edge and then extend horizontally (to the interior or exterior). Section 502.2/ 602.1 41

Slab Edge Insulation Section 502.2/ 602.1
This is an example of insulation cut at a 45-degree bevel cut this is a way to avoid bringing the insulation to the top of the slab edge so a carpet tack strip can be attached. Section 502.2/ 602.1 42

Below-Grade Walls  50% below grade Meet or exceed required R-values
Where 50% or less of a below-grade wall assembly is above grade (based on exterior surface area), the below-grade wall requirement from the Envelope Requirements may be used for the entire assembly. Below-grade wall insulation must extend down 10 feet or the the level of the floor whichever is less. Section 502.2/ 602.1 43

Defining Below-Grade Walls
Section 502.2/ 602.1 44

Ways to Insulate Basement Walls
Exterior Rigid Foam Interior Studs w/batts Section 502.2/ 602.1 45

Don’t forget to insulate rim joists
Above Grade Walls Insulate walls including those next to unconditioned spaces Insulation should not be compressed behind the wiring or plumbing; this reduces the R-value of insulation Be sure the insulation has filled the entire cavity, Batts that are cut too short will leave voids. For continuous insulation make sure there are no voids and the insulation is well bonded to the outside framing. Perimeter joists between floors must be insulated While not a requirement, in some climates it is important to insulate exterior corners and on or in headers over doors and windows to eliminate heat transfer through the surfaces. Don’t forget to insulate rim joists Section 502.2/ 602.1 46

Wall Insulation Section 502.2/ 602.1 47

No, No… Never cut the batts too short
Knee Wall Insulation No, No… Never cut the batts too short Section 502.2/ 602.1 48

Windows & Glass Doors Key Elements Glazing Area SHGC values U-Values
Section 502.2/ 602.1 49

Windows - SHGC Solar Heat Gain Coefficient
Requirements dependent on projection factor National Fenestration Rating Council (NFRC) tested Default SHGC range diagrams SHGC = SC x .87 Solar Heat Gain Coefficient This was already discussed in the mandatory requirements, but is also part of the window and glass door requirements in which some of the requirements are not mandatory. Section 502.2/ 602.1 50

U-Value Default Table for Windows Glazed Doors and Skylights
Windows – U-Factors Table 102.3(1) U-Value Default Table for Windows Glazed Doors and Skylights Frame Material and Product Type Single Glazed Double Glazed Metal without thermal break Operable (including sliding and swinging glass doors) Fixed Garden Window Curtain Wall Skylight Site-assembled sloped/overhead glazing 1.27 1.13 2.60 1.22 1.98 1.36 0.87 0.69 1.81 0.79 1.31 0.82 Metal with thermal break 1.08 1.07 1.11 1.89 1.25 0.65 0.63 0.68 0.70 Reinforced vinyl/metal clad wood 0.90 0.98 1.75 0.57 0.56 1.05 Wood/Vinyl/fiberglass 0.89 2.31 1.47 0.55 1.61 0.84 NFRC tested and certified or default window U-factor range Use assembly U-factor All windows must meet or exceed U-Factor is a measure of how well the assembly conducts heat. The lower the number, the better the assembly acts and an insulator. A window U-factor is based on the interior surface area of the entire assembly, including glazing, sash, curbing, and other framing elements. Center-of-glass U-factors cannot be used. The code requires windows, glass doors, and skylights to be rated by National Fenestration Rating Council and to have labels that show the rated u-factor and SHGC values for the glazing unit. If the windows, glass doors, and/or skylights are not rated, the appropriate default tables from the code can be used. Any glazing product that is double pane with tinted glass in a thermally broken frame (e.g., wood, vinyl, or aluminum with a thermal break) will meet the requirements for a fenestration U-factor of 0.60 and an SHGC of 0.60. Section 502.2/ 602.1 51

New Old NFRC Label Section 502.2/ 602.1
National Fenestration Rating Council (NFRC) product ratings are available on-line at Section 502.2/ 602.1 52

Roofs Requirements based on Meet or exceed R-values Assembly type
Continuous insulation Insulation between framing Meet or exceed R-values In some cases the WWR will affect the roof insulation requirement. Roof insulation in buildings with attics must be installed to allow for free circulation of air through the attic eave vents. R-values for roofs represent either cavity insulation (between framing) or insulating sheathing (continuous insulation). Metal buildings - there are two classes of metal building roofs. One class uses traditional techniques that drape the insulation over the purlin and fasten the metal roof sheets through the insulation directly to the purlin. The second class requires that a thermal block be placed between the metal roof sheet and purlin. A thermal block consists of foam blocks or other materials/techniques that prevent heat from migrating from the purlin directly to the metal roof sheet. Compressed fiberglass batt insulation does not qualify as a thermal block. First thing to look for is the attic access hatch is insulated to the same r-value as the plans and that weatherstripping has been installed around the hatch door to reduce infiltration. R-values are to be printed on the batt insulation or rigid foam board Blown-in insulation shall have a insulation certificate at or near the opening of the attic. The certificate should include: r-value of installed thickness initial installed thickness settled thickness coverage area number of bags installed Insulation markers must be installed every 300 square feet and are marked with the minimum installed thickness and the minimum settled thickness. Check insulation is installed uniformly to an even thickness throughout the attic and extends over the top of the exterior wall. Baffles should be installed at each soffit, cornice or eave vent to direct vent air up and over the top of the insulation Section 502.2/ 602.1 53

Standard Roof Truss Possibility of ice dam formations Ceiling insulation code requirements assume standard truss systems Cold corners contribute to condensation and mold growth Ceiling requirements in the prescriptive requirements of Chapters 5 & 6 assume standard trusses. Typically, when blowing in insulation into a standard roof truss system, the insulation will taper as it reaches the exterior wall plate lines. This is due to the slope of the truss and also the baffle that directs ventilation air up and over the insulation from the eave vents. The R-value listed in the Prescriptive Building Envelope table assume a standard roof truss system, but credit can be taken for if insulation is allowed to be installed full height over the exterior wall plate line. The credit is in a reduced insulation R-value. The use of Standard Truss systems can cause cold corners and also contribute to ice dam formations. Section 502.2/ 602.1 54

Raised Heel Truss Raised Heel/Energy Truss Credit
Insulate full height over exterior wall The Prescriptive Specification allows the substitution of an R-38 insulation, if the code requires an R-49, and an R-30, if the code requires an R-38, if the insulation allowed to be installed full height over the exterior wall plate line. This can be accomplished by either using an oversized truss, a raised heel truss, or by installing insulation with a higher R-value per inch thickness such as a fiberglass batt or rigid board insulation. Typically fiberglass batt insulation can be installed over the exterior wall plate line to the desired R-value and the remaining attic can utilize blown-in insulation. Section 502.2/ 602.1 55

Additions and Window Replacements
Additions < 500 ft2 can use Table Glazing area for additions (other than sunrooms) must be < 40% of gross wall and roof area of addition Skylight replacements shall have a maximum U-factor of 0.60 when installed in climates > 1,999 HDD Fenestration replacement must meet the SHGC req. in locations <3500 HDD This prescriptive path makes compliance determination easier for small additions. The path is not available for additions of conditioned space of 500 square feet or greater. Section / 602.4 56

Additions Compliance options for additions
Treat as a stand-alone building Bring entire building into compliance Addition 1. Treat the addition as a stand-alone building and ignore the common walls between the existing building and the addition. 2. Combine the existing building with the addition and bring the whole building up to compliance. Compliance can be harder to achieve if the existing building is quite old. Section / 602.4 57

Special Rules for Sunrooms
Sunroom addition defined: Area less than 500 ft2 Have > 40% glazing of gross exterior wall and roof area Separate heating or cooling system or zone Must be thermally isolated and not used as a kitchen or sleeping quarters Sunrooms do not have to be less 500 square feet. The 500 square feet meet the criteria for showing compliance to Table If the sunroom is larger than 500 square feet the prescriptive approach cannot be used for compliance. Section 58

Sunroom/Addition Requirements
2003 IECC Prescriptive Criteria Sunrooms Prescriptively: the two tables represent the difference in stringency for sunrooms vs. additions 59

Mechanical Systems & Equipment
Condensing furnace with electronic air filter system 60

Mechanical Systems Outline
503.1 General 503.2 Mechanical Equipment Efficiency 503.3 HVAC Systems Load Calculations Temperature and Humidity Controls System Controls Thermostatic Controls Heat Pumps Distribution Systems Piping Insulation Other Insulation Thicknesses Duct & Plenum Insulation Duct Construction High & Medium Pressure Duct Systems Low Pressure Duct Systems Sealing Required Mechanical Ventilation Transports Energy Balancing The minimum equipment efficiency requirements of Table are imposed on manufacturers and it would be rare to encounter any new equipment that did not meet these minimums. Load Calculations (Section ) Use design conditions specified in chapter 3 Calculations shall be performed in accordance with ASHRAE Handbook of Fundamentals or other equivalent method. Systems shall be sized to meet the load System Controls (Section ) Each dwelling unit shall be considered a zone and provided with at least one temperature control device HVAC Piping might have already been inspected during the Insulation Inspection, if not, it should be inspected during the final inspection. Duct & Plenum Insulation, Table the differences between 2000 and 2003 is the insulation values are now separated by duct location (supply/return). Also insulation values have increased slightly. Section 503 61

Mechanical Systems Overview
Major mechanical systems covered by the IECC Section 503 62

Equipment Efficiencies
Minimum equipment performance values from Table 503.2 Use data furnished by the manufacturer Performance data in accordance with NAECA National Appliance Energy Conservation Act (NAECA) Specifies equipment performance of heating and cooling equipment, water heaters, and other equipment Applicable equipment must meet NAECA before it can be sold in the United States The minimum equipment efficiency requirements of Table are imposed on manufacturers and it would be rare to encounter any new equipment that did not meet these minimums. Section 503.2 63

Efficiency Terms Part Load Performance
Annual Fuel Utilization Efficiency (AFUE) – gas heating equipment Heating Seasonal Performance Factor (HSPF) – residential heat pumps Seasonal Energy Efficiency Ratio (SEER) – residential air conditioners The Annual Fuel Utilization Efficiency (AFUE) is the efficiency level for gas heating equipment. New equipment typically ranges from about 78- to 96-percent AFUE. Higher AFUE ratings indicate more efficient equipment. The Heating Seasonal Performance Factor (HSPF) measures the heating efficiency for residential scale heat pumps. New equipment ranges from about 6.8 to 10.0 HSPF. The SEER measures the cooling efficiency for residential scale air conditioning. New equipment ranges from 10 to about 16 SEER. Section 503.2 64

Load Calculations Load Calculations
Use design conditions specified in Chapter 3 Calculations shall be performed in accordance with ASHRAE Handbook of Fundamentals or other equivalent method Systems shall be sized to meet the load Oversized equipment has a higher initial cost, a higher operating cost, provides less comfort, and the short-cycling reduces the equipment life expectancy. Any one of these is a good reason not to oversize. Heating and cooling system design loads for the purpose of sizing systems and equipment shall be determined in accordance with the procedures described in the ASHRAE Handbook of Fundamentals or an equivalent computation procedure, using the design parameters specified in Chapter 3 of the IECC. Although the code does not specifically require the use of load calculations, it is wise to check for such a requirement in the mechanical code for the jurisdiction in which the building is located. The 1997 ASHRAE Handbook of Fundamentals contains guidance on heating and cooling deisgn load calculations. Section 65

Temperature and Humidity Controls
System Controls Each dwelling unit shall be considered a zone and provided with at least one temperature control device Heat Pump Auxiliary Heat Heat pumps with supplementary electric resistance heat shall have controls to prevent heater operation when the load can be met by the heat pump alone (except defrost cycles) Humidistat Must be capable of being set to prevent the use of fossil fuels or electricity to reduce relative humidity below 60% or increase relative humidity above 30% While humidistats may be used for comfort purposes, most often the humidistat controls only the humidifier itself and is interlocked to permit operation of the humidifier only when the heating system is operating. Where the space conditioning control system is such that the humidistat does not control the heating and/or cooling equipment, this requirement would not apply. Section 66

Thermostatic Control Capabilities
Section Heating only 55°F or lower Cooling only 85°F or higher Both heating and cooling must be capable of a 5° deadband Exceptions Special occupancy/use as approved by the building official Thermostats that require manual changeover between heating and cooling There must be at least 5 degrees between the settings for heating and for cooling. Automatic changeover thermostats without the minimal 5 degree deadband could cause the space conditioning system to run continuously, alternating between heating and cooling. This would consume significant energy without benefit to the occupants. Section 67

HVAC Piping Insulation
Table Exceptions: Factory installed piping within HVAC equipment Piping that conveys fluids between 55 and 105 °F Piping which conveys fluids which have not been heated or cooled by through the use of fossil fuels or electricity The minimum insulation required in Table is expressed in inches of thickness and varies according to piping system type, fluid temperature range, and pipe size. Refer to the table for guidance on insulating piping. Section 68

Pipe Insulation (cont’d)
Distribution System - Minimum Pipe Insulation Table Be sure to check the insulation thickness against the system type and verify installation compliance. Section 69

Duct and Plenum Insulation
Table or where applicable ducts and plenums operate at static pressures > 2 in. w.g. Exceptions: Factory installed plenums, casings or ductwork that is part of the HVAC equipment Ducts within the conditioned space that they serve The minimum duct insulation requirements are expressed in R-values and vary based on duct location, usage for heating or cooling, annual degree days, and the temperature difference (TD) at design conditions between the space within which the duct is located and the design air temperature in the duct. Refer to the table for duct insulation requirements. Section 70

Duct Insulation Table Minimum Duct Insulation (revised 2001/2003) Duct insulation requirements have changed from the 2000 IECC to the In the 2000 IECC R5 or R3.3 was required and was based on annual cooling degree days or heating degree days whichever was more stringent. Now in 2003 the requirements are strictly based on hdd and more specific as to duct location (I.e. unconditioned basements, crawl spaces outside the building. Insulation requirements for ducts located outside the building envelope also apply to both supply and return. Ducts must be properly insulated to ensure that the supply air does not heat up (when the space calls for cooling) or cool down (when the space calls for heating). Section 71

Duct Construction High- and medium-pressure duct systems (static pressure > 2 in. w.g.) to be insulated and sealed If static pressure > 3 in. w.g. Shall be leak tested in accordance with Section Pressure classifications noted on construction documents Low-pressure duct systems (static pressure  2 in. w.g.) All longitudinal and transverse joints, seams and connections shall be securely fastened and sealed with welds, gaskets, mastics (adhesives), mastics-plus-embedded-fabric systems or tapes Exceptions: Continuously welded or locking longitudinal joints and seams operating at static pressures < 2inches w.g. Section 72

Duct Sealing Seal and securely fasten all joints, longitudinal and transverse seams and connections with: welds gaskets mastics mastic-plus-embedded fabric systems tapes Unlisted duct tape is not permitted as a sealant on any metal ducts Tapes and mastics used to seal ductwork shall be listed and labeled in accordance with UL 181 A or UL 181 B. Properly sealing ducts will ensure that the occupied spaces receive the correct amount of space conditioning and that the attic or crawlspace does not become conditioned space because of leaky ducts. Duct tape is not permitted as a sealant on any metal ducts This applies to supply and return air ducts plenums duct fittings dampers fans accessory air handling equipment and appliances Section 73

Duct Sealing Section 74

Distribution Systems (cont’d)
Mechanical Ventilation Systems shall be equipped with a readily accessible shutoff or volume damper and shutoff Automatic or gravity dampers shall be used for outdoor intakes and exhausts Transport energy A measure of proper duct design Air transport factor < 5.5 Balancing HVAC systems shall provide a means for balancing (i.e. dampers, temperature or pressure test connections, balancing valves, etc.) Energy for moving air through heat-recovery devices (HRV) is not included in determining the air transport factor. The damper mounted within a supply register qualifies as a means for balancing air systems even though it can contribute to air noise. Volume control dampers located at the take-offs usually contribute far less noise. Section 75

Service Hot Water Outline
504.1 Scope 504.2 Water Heaters, Storage Tanks & Boilers Performance Efficiency Combination Systems 504.3 Swimming Pools On-off Switch Pool Covers Time Clocks 504.4 Hot Water System Controls 504.5 Pipe Insulation 504.6 Conservation of Hot Water 504.7 Heat Traps The minimum equipment efficiency requirements of Table are imposed on manufacturers and it would be rare to encounter any new equipment that did not meet these minimums. Load Calculations (Section ) Use design conditions specified in chapter 3 Calculations shall be performed in accordance with ASHRAE Handbook of Fundamentals or other equivalent method. Systems shall be sized to meet the load System Controls (Section ) Each dwelling unit shall be considered a zone and provided with at least one temperature control device HVAC Piping might have already been inspected during the Insulation Inspection, if not, it should be inspected during the final inspection. Section 504 SHW 76

Service Water Heating (cont’d)
Summary of requirements Heat traps to reduce standby losses Pipe insulation to reduce distribution and standby losses Circulation loop temperature controls to reduce distribution losses Section 504 SHW 77

Heat Traps Required on noncirculating hot water systems Section 504.7
Heat traps stop hot water from rising into the distribution pipes and forming a natural circulation loop. Heat traps are required in the inlet and outlet piping of noncirculating water heaters. Some water-heating equipment has factory-installed integral heat traps. For equipment without factory-installed integral heat traps, heat traps must be purchased and installed in the inlet and outlet connections or field-fabricated by creating a loop or inverted U-shaped arrangement of the inlet and outlet pipes. Heat traps are not required on circulating systems. Heat traps are a simple and inexpensive means of preventing cooling of hot water in service water heaters by thermosyphoning of the hot water to higher elevated portions of the attached piping system. Thermosyphoning is based on the simple physical principle of natural convection. Given the opportunity, hot water will ten to rise and be displaced by cold water beneath it. The heat trap stops this process, thereby retaining the hot water within the insulated storage tank. Section 504.7 SHW 78

Auto-Circulating Systems
Insulated to levels in Table 504.5 Exception: Piping insulation is not required when the heat loss, without insulation, does not increase energy use Table 504.5 Minimum Pipe Insulation (Thickness in Inches) Service Water-Heating Temperatures Pipe Sizes Non-circulating run outs Circulating Mains and run outs Up to 1” Up to 1.25” 1.5” to 2” Over 2” 0.5 1.0 1.5 2.0 Pump Operation. For circulating water heating systems, an on-off switch is required to turn the pump off when a circulating hot water system is not in operation. Also, circulation system piping must be insulated. Circulating hot water systems must have manual or automatic controls that allow pumps to be conveniently turned off when the system is not in operation. If the pump is conveniently located (such as in a garage) the on/off switch may be located on or near the pump. If the pump is located in an inaccessible location (such as under the house or in an attic) the control must be located in a more convenient location – not on the pump. Circulation loop piping is required based on pipe diameter and fluid temperature. For example, a one-inch circulating main with 120°F water will be required to have ½ inch of insulation Section 504.4 SHW 79

Residential Energy Code Compliance

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Residential Energy Code Compliance

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