Title 24 Quick Reference Guide

Title 24 Quick Reference Guide

 

What’s New for 2013

The most significant changes in the 2013 Building Energy Efficiency Standards affecting residential buildings include the new requirements for high performance fenestration products.

There are two methods to comply with Title 24 requirements. Prescriptive and Performance. Due to the limiting factors and higher demands of the Prescriptive approach requirements, it is projected that over 90% of the projects under Title 24 jurisdiction will default to the Performance and calculated approach. Therefore we will initially address the Performance approach and criteria’s in this document. Secondary Prescriptive information will be addressed at the end of this document.

The reference below clears for compliance any fenestration products with a U‐Factor of .58 or better under the 2013 upgraded standard.

 

Performance Method:

 

The modeling procedures and requirements for compliance

§150.1

A. The prescribed mandatory measures and prescriptive requirements affect the design and operation of the building.  Mandatory measures, prescriptive requirements and operational schedules establish a minimum performance level which can be exceeded by other design measures and construction practices resulting in greater energy savings.

B. The performance approach is a more sophisticated compliance method and it offers greater design flexibility than the prescriptive approach. The performance approach may be used for any unique design element(s) that the user of compliance modeling software  believes can contribute to the building’s overall energy use.

C. The performance approach allows for more energy tradeoffs between building features, such as increasing HVAC equipment efficiency in order to allow more fenestration area.

Reference‐RESIDENTIAL COMPLIANCE MANUAL 2013 (1.4.2‐H):

Mandatory Measures

New mandatory U‐factor of 0.58 for vertical fenestrations products and skylights, Section 150.0(q).

Requirements for labeling – In lieu of the NFRC label a “Default Label” along with a “Compliance Certificate” can be used and must remain attached until the building inspector has verified its efficiencies. Note: The Compliance Certificate shall be signed by the person in charge of the building design.

The residential fenestration parameters are as follows:

  1. Air Leakage – A minimum of .3 or better is required on all products.
  2. U‐Factor – A minimum of .58 or better (lower numeric number) is required for the Performance approach.  Prescriptive approach requires .32 or better for all zones.
  3. RSHGC (Residential Solar Heat Gain Coefficient) – Even though this number does weigh in towards the performance and compliance of the over‐all building, there is no performance minimum requirement residentially. Prescriptively zones 1, 3 & 5 are exempt and all other zones are required to have a .25 or better.
  4. VT (Visible Transmission) – Not required for residential projects, but for identification purposes the VT number must be identified on the default label. The calculation formula is included in this document.  Each one of the four items above is addressed below in detail including references.

REFERENCES (BUILDING ENERGY EFFICIENCY STANDARDS 2013):

SECTION 110.6 – MANDATORY REQUIREMENTS FOR FENESTRATION PRODUCTS AND EXTERIOR DOORS

 

Air Leakage

Manufactured fenestration products and exterior doors shall have air infiltration rates not exceeding 0.3 cfm/ft² of window area, 0.3 cfm/ft² of door area for residential doors, 0.3 cfm/ft² of door area for nonresidential single doors (swinging and sliding), and 1.0 cfm/ft² for nonresidential double doors (swinging), when tested according to NFRC‐400 or ASTM E283 at a pressure differential of 75 Pascal’s (or 1.57 pounds/ft²), incorporated herein by reference.

EXCEPTION to Section 110.6(a) 1: Field‐fabricated fenestration and field‐fabricated exterior doors

 

U‐Factor

The fenestration product’s U‐factor shall be rated in accordance with NFRC 100, or use the applicable default U‐factor set forth in TABLE 110.6‐A.

Table 110.06-A

EXCEPTION 1 to Section 110.6(a)2: If the fenestration product is a vertical skylight or is a site‐built fenestration product in a building covered by the nonresidential standards with less than 1,000 square feet of site‐built fenestration, the default U‐factor may be calculated as set forth in Reference Nonresidential Appendix NA6.

EXCEPTION 2 to Section 110.6(a)2: If the fenestration product is an alteration consisting of any area replacement of glass in a skylight product or in a vertical site‐built fenestration product, in a building covered by the nonresidential standards, the default U‐factor may be calculated as set forth in Reference Nonresidential Appendix NA6.

 

Solar Heat Gain Coefficient (SHGC)

The fenestration product’s SHGC shall be rated in accordance with NFRC 200, or use the applicable default SHGC set forth in TABLE 110.6‐B.

Table 110.06-B

EXCEPTION 1 to Section 110.6(a)3: If the fenestration product is a skylight or is a vertical site‐built fenestration product in a building covered by the nonresidential standards with less than 1,000 square feet of site‐built fenestration, the default SHGC may be calculated as set forth in Reference Nonresidential Appendix NA6.

EXCEPTION 2 to Section 110.6(a)3: If the fenestration product is an alteration consisting of any area replacement of glass in a skylight product or in a vertical site‐built fenestration product, in a building covered by the nonresidential standards, the default SHGC may be calculated as set forth in Reference Nonresidential Appendix NA6.

 

Visible Transmittance (VT)

The fenestration product’s VT shall be rated in accordance with NFRC 200 or ASTM E972, or for default labeling purposes use the formulation below (applicable to residential and non‐residential).

NA6.4 Default Visible Transmittance, VT

(a) Equation NA6‐3 ‐ VT of Center of Glass (COG) calculation

VTT = VTF x VTC

Where:
VTT = Is the Total Performance of the fenestration including glass and frame

VTF = 0.53 for projecting windows, such as casement and awning windows
VTF = 0.67 for operable or sliding windows
VTF = 0.77 for fixed or non‐operable windows

VTC = Center of glass VT is calculated in accordance with NFRC 200 Section 4.5.1.1 or NFRC 202 (provided by
glass manufacturer).

EXCEPTION 1 to Section 110.6(a)4: If the fenestration product is a skylight or is a vertical site‐built fenestration product in a building covered by the nonresidential standards with less than 1,000 square feet of site‐built fenestration, the default VT may be calculated as set forth in Reference Nonresidential Appendix NA6.
EXCEPTION 2 to Section 110.6(a)4: If the fenestration product is an alteration consisting of any area; replacement of glass in a skylight product or in a vertical site‐built fenestration product in a building covered by the nonresidential standards, the default VT may be calculated as set forth in Reference Nonresidential Appendix NA6.

Labeling Requirements (Default vs NFRC)

In lieu of the NFRC label a “Default Label” along with a “Compliance Certificate” can be used and must remain attached until the building inspector has verified its efficiencies. As long as the Air Leakage and U‐Factor minimums have been met and the Solar Heat Gain Coefficient has been identified, a Default Label based on the Default Table, may be used in lieu of an NFRC Label. Please note that while the VT is not required residentially from a performance stand point, the value must be identified on the default label.

REFERENCES (BUILDING ENERGY EFFICIENCY STANDARDS 2013) – Section 110.6 – 5:

Labeling Requirements:

1.  Temporary labels

A.  Every manufactured fenestration product shall have attached to it a clearly visible temporary label that lists the U‐factor, the solar heat gain coefficient (SHGC) and Visible Transmittance (VT) and that certifies compliance with the air leakage requirements of Section 110.6(a)

B.  U‐factor, SHGC and VT shall be determined by either:

i.  Fenestration products rated and certified using NFRC 100, NFRC 200, NFRC 202 NFRC 203 or NFRC 400 Rating Procedures. The manufacturer shall stipulate that the ratings were determined in accordance with applicable NFRC procedures. For manufactured fenestration products, a temporary label certificate approved by the supervisory entity (NFRC) meets the requirements of this section. For component modeling and site‐built fenestration products, a label certificate approved by the supervisory entity (NFRC) meets the requirements of this section.

ii.  For manufactured or site‐built fenestration products not rated by NFRC, a temporary label with the words “CEC Default U‐factor,” followed by the appropriate default U‐factor specified in Section 110.6(a)2 and with the words “CEC Default SHGC,” followed by the appropriate default SHGC specified in Section 110.6(a)3 and with the words “CEC Default VT,” followed by the appropriate VT as specified in Section 110.6(a)4, meets the requirements of this Subsection B.

C.  Temporary labels shall also certify that the product complies with the air leakage requirements of Section 110.6(a)1 of the  Standards.

2.  Permanent labels

NFRC Rated products shall have a permanent label that is either a stand‐alone label, an extension or tab of an existing permanent certification label being used by the manufacturer/responsible party, or series of marks or etchings on the product. The permanent label, coupled with observable product characteristics, can be used to trace the product to certification information on file with the supervisory entity or to a directory of certified products, published by the supervisory entity. For CMA and site‐built fenestration products, a label certificate approved by the supervisory entity meets the requirements of this section.

EXCEPTION to Section 10‐111

(a)  Field‐fabricated fenestration products.
(b)  Certification Requirements.

1.  Certification to default ratings. The manufacturer shall certify on the Default Label that the product’s U‐factor, SHGC and VT meets the default criteria in Sections 110.6(a)2, 110.6(a)3 and 110.6(a)4; and:

A. A temporary label, affixed to the product, that meets the requirements of Section 10‐111(a)1B meets this requirement.

B. If the product claims the default U‐factor for a thermal‐break product, the manufacturer shall also certify on the label that the product meets the thermal‐break product criteria, specified on the default table, on which the default value is based. Placing the terms “Meets Thermal‐Break Default Criteria” on the default temporary label or default label certificate meets this requirement.

 

Labeling:

Fenestration products shall:

A. Have a temporary label for manufactured fenestration products or a label certificate when the Component Modeling Approach (CMA) is used and for site‐built fenestration meeting the requirements of Section 10‐ 111(a)1. The label listing the certified U‐factor, SHGC and VT, shall not be removed before inspection by the enforcement agency. The temporary label shall certify that the air leakage requirements of Section 110.6(a)1 are met for each product line; and

B. Have a permanent label or a label certificate when the Component Modeling Approach (CMA) is used and for site‐built fenestration meeting the requirements of Section 10‐111(a)2 if the product is rated using NFRC procedures.

C. Fenestration Acceptance Requirements.
Before an occupancy permit is granted, site‐built fenestration products in other than low‐rise residential buildings shall be certified as meeting the Acceptance Requirements for Code Compliance, as specified in the Reference Nonresidential Appendix NA7 to ensure that site‐built fenestration meet Standards requirements, including a matching label certificate for product(s) installed and be readily accessible at the project location.  A Certificate of Acceptance certifying that the fenestration product meets the acceptance requirements shall be completed, signed and submitted to the enforcement agency.

EXCEPTION to Section 110.6

(a) Fenestration products removed and reinstalled as part of a building alteration or addition.

(b) Installation of Field‐fabricated Fenestration and Exterior Doors. Field‐fabricated fenestration and field-fabricated exterior doors may be installed only if the compliance documentation has demonstrated compliance for the installation using U‐factors from TABLE 110.6‐A and SHGC values from TABLE 110.6‐B. Field‐fabricated fenestration and field‐fabricated exterior doors shall be caulked between the fenestration products or exterior door and the building, and shall be weather‐stripped.

EXCEPTION to Section 110.6(b): Unframed glass doors and fire doors need not be weather stripped or caulked.

 

Default Labeling:

In lieu of the NFRC Labeling, a “Default Label” is compliant.
The below references clearly state that the default tables do apply to manufactured fenestration products.

Table 3-1A

Table 3-1B

Reference‐Residential Compliance Manual 2013:

Labeling Mandatory Requirements Residential Compliance Manual 2013 (3.5.5)

Applicable Sections: §10‐111(a); §110.6(a)5

A. Default Temporary Label

The manufacturer can also choose to use Energy Commission (CEC) default values from TABLE 110.6‐A for Ufactors and TABLE 110.6‐B for SHGC. If default values are used, the manufacturer must attach a temporary label meeting the following specific requirements (permanent etching labels are not required). Product shall meet the air infiltration requirements of  §110.6(a)1, U‐factor criteria of §110.6(a)2, and SHGC criteria of §110.6(a)3 in the Building Energy Efficiency Standards for Residential and Nonresidential Buildings.

Although there is no exact format for the default temporary label:

• It must be clearly visible
• Large enough for the enforcement agency field inspectors to read easily
• Must include all information required by the standards.

The minimum suggested label size is 4 in. x 4 in. and the label must have the following words at the bottom of the label as noted in Figure 3‐2;

“Product meets the air infiltration requirements of §110.6(a)1, U‐factor criteria of §110.6(a)2, SHGC criteria of §110.6(a)3 and VT criteria of §110.6(a)4 of the 2013 California Building Energy Efficiency Standards for Residential and Nonresidential Buildings.”

The manufacture ensures the U‐factor and SHGC default values should be large enough to be visible from 4 feet away. The manufacturer ensures the appropriate check-boxes are checked and indicated on default label.

Sample Default Temporary Label

Default Tables provided by the commission:

The default tables are based upon the expected performance as simulated by the program used by the NFRC and uses a default value. This value is subject to review and updates by the Energy Commission and may change in the future.

 

REFERENCES (BUILDING ENERGY EFFICIENCY STANDARDS 2013):

SECTION 10‐112 – CRITERIA FOR DEFAULT TABLES

(a) The Commission shall maintain tables of default U‐factors and SHGCs for use as an alternative to U‐factors and SHGCs derived based on the NFRC Rating Procedure. The default values shall meet the following criteria:

1. The values shall be derived from simulations of products using the same computer simulation program(s) used in the NFRC Rating Procedure.

2. The default values shall be set so that they do not provide to any significant number of products a lower Ufactor or SHGC than those products would obtain if they were rated using the full NFRC Rating Procedure.

(b) The Commission shall periodically review and revise the default tables as necessary to ensure that the criteria are met.

Alert: Locally adopted energy standards maybe imposed by municipalities that exceed Title 24 requirements.

REFERENCES (BUILDING ENERGY EFFICIENCY STANDARDS 2013):

SECTION 10‐106 – LOCALLY ADOPTED ENERGY STANDARDS

(a) Requirements. Local governmental agencies may adopt and enforce energy standards for newly constructed buildings, additions, alterations, and repairs to existing buildings provided the Energy Commission finds that the standards will require buildings to be designed to consume no more energy than permitted by Title 24, Part 6.

(b) Documentation Application. Local governmental agencies wishing to enforce locally adopted energy standards shall submit an application with the following materials to the Executive Director:

1. The proposed energy standards.
2. The local governmental agency’s findings and supporting analyses on the energy savings and cost effectiveness of the proposed energy standards.
3. A statement or finding by the local governmental agency that the local energy standards will require buildings to be designed to consume no more energy than permitted by Part 6.
4. Any findings, determinations, declarations or reports, including any negative declaration or environmental impact report, required pursuant to the California Environmental Quality Act, Pub. Resources Code Section 21000 et seq.

 

Other Exceptions

Historical Buildings‐Residential Compliance Manual 2013 (1.5.4)

Exception 1 to §100.0(a) states that qualified historic buildings, as regulated in the California Historical Building Code (Title 24, Part 8) or California Building Code, Title 24, Part 2, Volume I, Chapter 34, Division II are not covered by the Building Energy Efficiency Standards.

Exempt Buildings‐Residential Compliance Manual 2013 (1.5.5)

The following building types are exempt from the prescriptive and performance standards:

A. Seasonally occupied agricultural housing limited by state or federal agency contract to occupancy not more than 180 days in any calendar year (EXCEPTION 1 to §100.0(e)2D); however, these buildings must comply with the applicable mandatory requirements.

B. Low‐rise residential buildings that use no energy obtained from a depletable source for either lighting or water heating and obtain space heat from wood heating or other non-mechanical system: however, these buildings must comply with the applicable mandatory requirements.

C. Based on discretion of building officials, temporary buildings, temporary outdoor lighting or temporary lighting in an unconditioned building, or structures erected in response to a natural disaster (EXCEPTION 2 to §100.0(a)). These buildings may also be exempt from the mandatory and prescriptive requirements of the Standards.

Additions, Alterations and Repairs Residential Compliance Manuel 2013 (1.5.7)

• §100.1(b)
• §150.2(a)
• §150.2(b)

Additions, alterations, and repairs are common construction projects for California homeowners. The Standards apply to both additions and alterations, but not to repairs.

A. Additions are changes to an existing building that increase both conditioned floor area and volume.

B. Alterations, that are not additions, are changes to a building’s envelope, space conditioning system, water heating system or lighting system.

C. Repairs are the reconstruction or renewal of any part of an existing building for the purpose of its maintenance and are not under the scope of the Standards. Replacement of any component systems (i.e. re‐roofing), or equipment for which there are requirements in the Standards is considered an alteration and not a repair.

Fenestration Types‐Residential Compliance Manuel 2013 (3.5.1‐B)

GLAZED DOORS
Glazed door is an exterior door having a glazed area of 50 percent or more of the area of the door. These doors are typically installed in exterior walls that separate conditioned space from exterior ambient or unconditioned space. When the door is less than 50 percent it will no longer be considered a glazed door but is a door. The glass area will still have to be counted towards the overall glass area of the conditioned space.

Fenestration U‐factor-Residential Compliance Manual 2013 (3.5.7)

Please note that the U‐Factor of .58 as a minimum is a weighted average of all of the products of the project.  This will allow you to include in the project units that don’t meet the .58 minimum as long as, the average of the entire project units meet the .58 minimum. Furthermore, if you are just replacing one unit of Up to 10 ft2 or 0.5% of conditioned floor area (whichever is greater) that particular unit will be exempt from the U‐Factor requirements. Please see reference below:

Reference (Residential Compliance Manual 2013)

Applicable Section: §150.0(q)

With the 2013 update, the mandatory maximum U‐factor is set by §150.0(q) for fenestration including skylights to be at maximum U‐factor of 0.58. While there is an allowance for area weighted averaging, this will limit the use of single pane products. Up to 10 ft2 or 0.5% of conditioned floor area (whichever is greater) is exempt from the maximum U‐factor requirement.

 

Other Requirements

Construction Phase Documentation (CF2R) ‐Residential Compliance Manual 2013 (2.3.3)

C. Fenestration/Glazing. The Certificate of Installation is completed and signed by the contractor responsible for installing the windows and skylights. The U‐factor, SHGC, area, number of panes, etc. for each window and skylight are documented. The installer also verifies that all windows and skylights are installed according to the manufacture recommendations.

Appendices

NA6.4 Default Visible Transmittance, VT
(a) Equation NA6‐3 ‐ VT of Center of Glass (COG) calculation

VTT = VTF x VTC

Where:
VTT = Is the Total Performance of the fenestration including glass and frame
VTF = 0.53 for projecting windows, such as casement and awning windows
VTF = 0.67 for operable or sliding windows
VTF = 0.77 for fixed or non‐operable windows
VTF= 0.88 for curtain wall/storefront, Site‐built and manufactured non‐curb mounted skylights
VTF = 1.0 for Curb Mounted manufactured Skylights
VTC = Center of glass VT is calculated in accordance with NFRC 200 Section 4.5.1.1 or NFRC 202

 


 

Prescriptive Method and Limitations:

 

As previously mentioned there are stringent requirements and limitations to following this method that will offer little flexibility as well as additional potential expenses.

Reference‐Residential Compliance Manual 2013

Prescriptive Compliance Approach-Residential Compliance Manual 2013 (3.3.2)

Standards Table 150.1‐A (Below)

A. The prescriptive requirements are the simplest way to comply with the building envelope requirements but offer little flexibility. If each and every prescriptive requirement is met, the building envelope complies with the standards. The prescriptive envelope requirements are prescribed in §150.1 which include Table 150.1‐A.

B. The prescriptive compliance approach consists of meeting specific requirements for each envelope component, plus meeting all minimum mandatory requirements, such as mandatory levels of insulation.  Prescriptive requirements apply to:

1. Roofs and ceilings,
2. Exterior roofing products
3. Exterior walls
4. Floors

Fenestration must meet prescriptive efficiency values and have a maximum area of 20% of the window‐to‐wall ratio conditioned floor area (CFA). The efficiency values are specified for the maximum U‐factor, maximum Solar Heat Gain Coefficient (SHGC) and maximum west facing area of 5% of the CFA. Specific requirements are made for glazing in doors, tubular skylights, non‐tubular skylights, and chromatic type glazing (§150.1(c)3A).

Table 3-3 Max U-Factors SHGC Fen Area by Climate Zone

Table 150.1-A Component Package-A

(Click image to enlarge)

Prescriptive Requirements Reference‐Residential Compliance Manual 2013 (3.5.8)

Applicable Section: §150.1(c)3

Prescriptive requirements described in this chapter typically refer to Package A or Table 150.1‐A of the Standards. The maximum U‐factor required by prescriptive Package A for all climate zones is 0.32 and the maximum Solar Heat Gain Coefficient (SHGC) is 0.25 or lower for dwellings in climate zones 2, 4, and 6‐16.  Homes constructed in climate zones 1, 3, and 5 have no maximum SHGC requirements. The requirements apply to fenestration products without consideration of insect screens or interior shading devices. With some exceptions, some fenestration products may exceed the prescriptive requirement as long as the U‐factor and SHGC of windows, glazed doors and skylights can be area‐weight averaged together to meet the prescriptive requirement using the WS‐2R form in Appendix A of this manual.

 

DYANMIC GLAZING COMPLIANCE Reference‐Residential Compliance Manual 2013 (3.5.10)

Glazed Doors §110.6‐Residential Compliance Manual 2013 (E)

The following rules apply to doors with glass:

Any door that is more than one‐half glass is considered a glazed door and must comply with the mandatory other requirements applicable to a fenestration product. Up to 3 ft2 of glass in a door is exempt from the U‐factor and SHGC requirements (or can be considered equivalent to the Package A values). The U‐factor and SHGC shall be based on either the NFRC values for the entire door including glass area, or use default values in Table 110.6‐ A for the U‐factor and Table 110.6‐B for the SGHC. If the door is made up of less than 50 percent, the opaque part of the door is ignored in the prescriptive approach, but in the performance method it is assumed a default U‐factor of 0.50. The glass area of the door is calculated as the sum of all glass surfaces plus 2 inches on all sides of the glass to account for a frame.

Bay Windows -Residential Compliance Manual 2013 (H)

For bay windows that come with an NFRC rating for the entire unit, compliance is determined based on the rough opening area of the entire unit, applying the NFRC U‐factor and SHGC. If the unit U‐factor and SHGC do not meet the package requirements or area‐weighted average, the project must show compliance using the performance approach.

Fenestration -Residential Compliance Manual 2013 (9.4.4)

Fenestration which is new or replacement (altered) glazing – including skylights ‐must meet the maximum U-factor requirement in one of three ways:

1. Every fenestration product (glazed opening) meets the mandatory maximum U‐factor of 0.58; or

2. All new or replacement fenestration combined meet the mandatory maximum of 0.58 U‐factor using an area weighted average calculation; or

3. The area of new and replacement fenestration up to 10 ft2 or 0.5% of the conditioned floor area (CFA), whichever is greater, is exempt from the U‐factor requirement per Exception to §150.0(q).

Example: an existing 2,500 ft2 house undergoes an alteration with all the existing windows being replaced. The owner may install up to 12.5 ft2 of new glazing (i.e., up to 0.5% of 2,500 ft2) without meeting the maximum U-factor of 0.58.  If the overall alterations meet the Standards with the prescriptive or performance approach (see Sections 9.6 Consistent with Exception 1 to §150.1(c)3A: For each dwelling unit, up to 3 square feet of new glazing area installed in doors and up to 3 square feet of new tubular skylight area with dual‐pane diffusers shall not be required to meet or be included in the area weighted average fenestration calculation to meet the mandatory requirement of §150.0(q).

Greenhouse Windows -Residential Compliance Manual 2013 (9.4.5)

Greenhouse or garden windows are special windows that project from the façade of the building and are typically five sided structure. An NFRC‐rated U‐factor for greenhouse windows is typically quite high and may not meet the mandatory requirements for the fenestration U‐factor of 0.58. The three ways to meet this mandatory measure for greenhouse windows are:

  • Must have a maximum U‐factor of 0.58 or better; or
  • Use the area‐weighted average for all new and replacement fenestration with a combined mandatory maximum of 0.58 U‐factor as per §150.0(q)2; or

The Exception to §150.0(q)1 for up to 10 ft2 or 0.5% of CFA, whichever is greater; or When using the performance approach, Exception 1 to s. 150.2(b) states that any dual glazed greenhouse or garden window installed as part of an alteration complies automatically with the U‐factor requirements of s. 150.1(c)3.  However, these windows are not exempt from the SHGC requirements of s. 150.1(c)3.

CEC Reference links:

  1. 2013 Building Energy Efficiency Standards
  2. 2013 Residential Compliance Manual
  3. 2013 Nonresidential Appendices

The above information is helpful in deciphering the new Title 24 requirements for fenestrations.