1. Home
  2. Modeling Guidelines
  3. 3.0 Building Descriptors Reference
  4. 3.5 Building Envelope Data

3.5.7 Fenestration

Note that fenestration includes windows, doors that have more than 50% glazed area, and skylights. A skylight is fenestration that has a tilt of less than 60° from horizontal.

Fenestration Name
Applicability All fenestration, optional input
Definition A unique name or code that relates the fenestration to the design documents and a parent surface.
Units Text, unique
Input Restrictions No restrictions
Baseline Rules Not applicable
Fenestration Type (Vertical Fenestration)
Applicability All vertical fenestration
Definition This is a classification of vertical fenestration that determines the thermal performance and solar performance requirement for vertical fenestration.
Units

List (ASHRAE Standard 90.1-2007): Nonmetal framing (all); metal framing (curtainwall/storefront); metal framing (entrance door); or metal framing (all other)

List (ASHRAE Standard 90.1-2001): Fixed or Operable
Input Restrictions No restrictions, other than that the vertical fenestration type must agree with the type specified on the construction documents or the as-built drawings.
Baseline Rules Same as the proposed design
Fenestration Type (Skylights)
Applicability All skylights
Definition This is a classification of skylights that determines the thermal performance and solar performance requirement for vertical fenestration.
Units List: Glass skylight with curb; plastic skylight with curb; or skylights with no curb
Input Restrictions No restrictions, other than the skylight types specified must agree with the construction documents or the as-built drawings.
Baseline Rules Same as the proposed design
Fenestration Geometry
Applicability All fenestration
Definition Fenestration geometry defines the position and dimensions of the fenestration surface within its parent surface and the identification of the parent surface. The orientation and tilt is inherited from the parent surface. The details of how the coordinate system is implemented may vary between rating software programs.
Units Data structure: opening
Input Restrictions There are no restrictions, other than a match with the construction drawings or as-built drawings. Specification of the fenestration position within its parent surface is required for the following conditions: 1) exterior shading is modeled from buildings, vegetation, other objects; or 2) if daylighting is modeled within the adjacent space.
Baseline Rules

The geometry of the fenestration shall be identical to the proposed design with the following exceptions:

  • If the gross area of all windows in the building exceeds 40% of the gross above-grade exterior wall area in the building, the dimensions of each window in the baseline building shall be reduced in size such that the window area in the baseline building is equal to 40% of the above-grade exterior wall area.
  • If the gross area of skylights in the building exceeds 5% of the gross roof area, the dimensions of each skylight shall be reduced in size such that the skylight area in the proposed design is equal to 5% of the gross roof area.
Fenestration Construction
Applicability All fenestration
Definition A collection of values that together describe the performance of a fenestration system. The values that are used to specify the criteria are U-factor, SHGC and VT . Data may be specified in other ways, however, as long as the data are supported by appropriate tests.
Units Data structure: fenestration construction
Input Restrictions Performance information for fenestration shall be developed from NFRC test procedures or shall be taken from the default values in Appendix A of the baseline standard. Values entered shall be consistent with the specifications and the construction documents.
Baseline Rules The requirements for vertical fenestration U factor, Solar Heat Gain Coefficient, and Visible light transmission by climate zone and framing type are found in [bookref id="baseline-building-criteria-for-vertical-glazing-for-90.1-2001"] and for skylight inputs in [bookref id="Baseline Building Criteria for Skylights" id="baseline-building-criteria-for-skylights"]. In cases where there is no requirement (NR) for SHGC or VT, the baseline building shall be equal to the proposed design.

[table title="Baseline Building Criteria for Vertical Glazing for 90.1 2001" id="baseline-building-criteria-for-vertical-glazing-for-90.1-2001"]

Building type Climate Zone Window to Wall Ratio Standard Design
Assembly U-factor Assembly SHGC Assembly VT
Fixed Operable All North All North
Nonresidential 1 0-30.0% 1.22 1.27 0.25 0.61 0.25 0.61
30.1-40.0% 1.22 1.27 0.25 0.44 0.25 0.44
2 0-40.0% 1.22 1.27 0.25 0.61 0.25 0.61
3(A,B) 0-10.0% 0.57 0.67 0.39 0.49 0.39 0.49
10.1-20.0% 0.57 0.67 0.25 0.49 0.25 0.49
20.1-40.0% 0.57 0.67 0.25 0.39 0.25 0.39
3(C) 0-10.0% 1.22 1.27 0.61 0.82 0.61 0.82
10.1-40.0% 1.22 1.27 0.39 0.61 0.39 0.61
4 0-40.0% 0.57 0.67 0.39 0.49 0.50 0.62
5 0-10.0% 0.57 0.67 0.49 0.49 0.62 0.62
10.1-40.0% 0.57 0.67 0.39 0.49 0.50 0.62
6 0-10.0% 0.57 0.67 0.49 0.49 0.62 0.62
10.1-40.0% 0.57 0.67 0.39 0.49 0.50 0.62
7 0-40.0% 0.57 0.67 0.49 0.64 0.49 0.64
8 0-40.0% 0.46 0.47 NR NR NR NR
Residential   1 0-30.0% 1.22 1.27 0.25 0.61 0.25 0.61
30.1-40.0% 1.22 1.27 0.25 0.44 0.25 0.44
2 0-10.0% 1.22 1.27 0.39 0.61 0.39 0.61
10.1-40.0% 1.22 1.27 0.25 0.61 0.25 0.61
3(A,B) 0-10.0% 0.57 0.67 0.39 0.49 0.39 0.49
10.1-20.0% 0.57 0.67 0.25 0.49 0.25 0.49
20.1-40.0% 0.57 0.67 0.25 0.39 0.25 0.39
3(C) 0-10.0% 1.22 1.27 0.61 0.82 0.61 0.82
10.1-20.0% 1.22 1.27 0.61 0.61 0.61 0.61
20.1-30.0% 1.22 1.27 0.39 0.61 0.39 0.61
30.1-40.0% 1.22 1.27 0.34 0.61 0.34 0.61
4 0-40.0% 0.57 0.67 0.39 0.49 0.50 0.62
5 0-10.0% 0.57 0.67 0.49 0.49 0.62 0.62
10.1-40.0% 0.57 0.67 0.39 0.39 0.50 0.50
6 0-10.0% 0.57 0.67 0.49 0.64 0.62 0.81
10.1-40.0% 0.57 0.67 0.39 0.49 0.50 0.62
7 0-40.0% 0.57 0.67 0.49 0.64 0.62 0.81
8 0-40.0% 0.46 0.47 NR NR NR NR
Semiheated 1-8 0-40.0% 1.22 1.27 NR NR NR NR

[table title="Baseline Building Criteria for Vertical Glazing for 90.1 2007 and 90.1-2010" id="baseline-building-criteria-for-vertical-glazing-for- 90.1-2007"]

Building type Fenestration Type Climate Zone Standard Design
U-factor SHGC VT
Nonresidential Non-Metal Framing 1 1.20 0.25 0.32
2 0.75 0.25 0.32
3 0.65 0.25 0.32
4 0.40 0.40 0.51
5,6 0.35 0.40 0.51
7,8 0.35 0.45 0.57
Metal Framing
Curtainwall/ Storefront		 1 1.20 0.25 0.32
2 0.70 0.25 0.32
3 0.60 0.25 0.32
4 0.50 0.40 0.51
5,6 0.45 0.40 0.51
7,8 0.40 0.45 0.57
Metal Framing
Entrance Door		 1 1.20 0.25 0.32
2 1.10 0.25 0.32
3 0.90 0.25 0.32
4 0.85 0.40 0.51
5,6 0.80 0.40 0.51
7,8 0.80 0.45 0.57
Nonresidential (Continued) Metal Framing
All Other		 1 1.20 0.25 0.32
2 0.75 0.25 0.32
3 0.65 0.25 0.32
4 0.55 0.40 0.51
5,6 0.55 0.40 0.51
7,8 0.45 0.45 0.57
Residential Non-Metal Framing 1 1.20 0.25 0.32
2 0.75 0.25 0.32
3 0.65 0.25 0.32
4 0.40 0.40 0.51
5,6 0.35 0.40 0.51
7,8 0.35 NR NR
Metal Framing
Curtainwall/ Storefront		 1 1.20 0.25 0.32
2 0.70 0.25 0.32
3 0.60 0.25 0.32
4 0.50 0.40 0.51
5,6 0.45 0.40 0.51
7,8 0.40 NR NR
Metal Framing
Entrance Door		 1 1.20 0.25 0.32
2 1.10 0.25 0.32
3 0.90 0.25 0.32
4 0.85 0.40 0.51
5,6 0.80 0.40 0.51
7,8 0.80 NR NR
Metal Framing
All Other		 1 1.20 0.25 0.32
2 0.75 0.25 0.32
3 0.65 0.25 0.32
4 0.55 0.40 0.51
5,6 0.55 0.40 0.51
7,8 0.45 NR NR
Residential Non-Metal Framing 1- 5 1.20 NR NR
6- 8 0.65 NR NR
Metal Framing
Curtainwall/ Storefront		 1- 5 1.20 NR NR
6- 8 0.60 NR NR
Metal Framing
Entrance Door		 1- 5 1.20 NR NR
6- 8 0.90 NR NR
Residential (Continued) Metal Framing
All Other		 1- 5 1.20 NR NR
6- 8 0.65 NR NR

[table title="Baseline Building Criteria for Skylights" id="baseline-building-criteria-for-skylights"]

Proposed Design Applicable Standard Climate Zone % of Roof Standard Design
U-factor SHGC VT
Glass Skylight with Curb 90.1 – 2001
&
90.1 - 2007		 1,2 0-2.0% 1.98 0.36 0.46
2.1-5.0% 1.98 0.19 0.24
3 (A,B) - (all climate zone 3 for 2007) 0-2.0% 1.17 0.39 0.50
2.1-5.0% 1.17 0.19 0.24
3 (C)
(2001 only)		 0-2.0% 1.98 0.61 0.77
2.1-5.0% 1.98 0.39 0.50
4,5 0-2.0% 1.17 0.49 0.62
2.1-5.0% 1.17 0.39 0.50
6 0-5.0% 1.17 0.49 0.62
7 0-2.0% 1.17 0.68 0.68
2.1-5.0% 1.17 0.64 0.64
8 0-2.0% 0.98 0.55 0.63
Plastic Skylight with Curb 90.1 - 2001
&
90.1 - 2007		 1 0-2.0% 1.90 0.34 0.41
2.1-5.0% 1.90 0.27 0.32
2 0-2.0% 1.90 0.39 0.47
2.1-5.0% 1.90 0.34 0.41
3,4 0-2.0% 1.30 0.65 0.78
2.1-5.0% 1.30 0.34 0.41
5 0-2.0% 1.10 0.77 0.92
2.1-5.0% 1.10 0.62 0.74
6 0-2.0% 0.87 0.71 0.85
2.1-5.0% 0.87 0.58 0.70
7 0-2.0% 0.87 0.77 0.92
2.1-5.0% 0.87 0.71 0.85
8 0-2.0% 0.61 0.59 0.64
Skylight without Curb 90.1 – 2001
&
90.1 – 2007		 1,2 0-2.0% 1.36 0.36 0.46
2.1-5.0% 1.36 0.19 0.24
3 (A,B) - (all climate zone 3 for 2007) 0-2.0% 0.69 0.39 0.50
2.1-5.0% 0.69 0.19 0.24
3 (C)
(2001 only)		 0-2.0% 1.36 0.61 0.77
2.1-5.0% 1.36 0.39 0.50
4,5 0-2.0% 0.69 0.49 0.62
2.1-5.0% 0.69 0.39 0.50
6 0-5.0% 0.69 0.49 0.62
7 0-2.0% 0.69 0.68 0.68
2.1-5.0% 0.69 0.64 0.64
8 0-5.0% 0.58 0.55 0.63
External Shading Devices
Applicability All fenestration
Definition Devices or building features, such as overhangs, fins, shading screens, and setbacks of windows from the exterior face of the wall, that are documented on the construction documents and shade the glazing. Objects that shade the building but that are not part of the building and parts of the building that cause the building to shade itself are also modeled, but are not a part of this building descriptor. See Shading of the Building Site.
Units Data structure: opening shade
Input Restrictions No restrictions other than that the inputs must match the construction documents
Baseline Rules The baseline building is modeled without external shading devices.
Internal Shading Devices
Applicability All fenestration
Definition Curtains, blinds, louvers, or other devices that are applied on the room side of the glazing material. Glazing systems that use blinds between the glazing layers are also considered internal shading devices. Glass coatings or components or treatments of the glazing materials are addressed through the Fenestration Construction building descriptor.
Units Data structure
Input Restrictions Internal shading shall not be modeled in the proposed design, unless it is automatically controlled, based on input from an astronomical timeclock, an exterior pyronometer, or other sensors. The control algorithm shall be documented on the construction documents. Interior shades without automatic controls shall not be modeled.
Baseline Rules The baseline building shall be modeled without interior shades.
90.1-2007

Note that fenestration includes windows, doors that have more than 50% glazed area, and skylights. A skylight is fenestration that has a tilt of less than 60° from horizontal.

Fenestration Name
Applicability All fenestration, optional input
Definition A unique name or code that relates the fenestration to the design documents and a parent surface.
Units Text, unique
Input Restrictions No restrictions
Baseline Rules Not applicable
Fenestration Type (Vertical Fenestration)
Applicability All vertical fenestration
Definition This is a classification of vertical fenestration that determines the thermal performance and solar performance requirement for vertical fenestration.
Units

List (ASHRAE Standard 90.1-2007): Nonmetal framing (all); metal framing (curtainwall/storefront); metal framing (entrance door); or metal framing (all other)
Input Restrictions No restrictions, other than that the vertical fenestration type must agree with the type specified on the construction documents or the as-built drawings.
Baseline Rules Same as the proposed design
Fenestration Type (Skylights)
Applicability All skylights
Definition This is a classification of skylights that determines the thermal performance and solar performance requirement for vertical fenestration.
Units List: Glass skylight with curb; plastic skylight with curb; or skylights with no curb
Input Restrictions No restrictions, other than the skylight types specified must agree with the construction documents or the as-built drawings.
Baseline Rules Same as the proposed design
Fenestration Geometry
Applicability All fenestration
Definition Fenestration geometry defines the position and dimensions of the fenestration surface within its parent surface and the identification of the parent surface. The orientation and tilt is inherited from the parent surface. The details of how the coordinate system is implemented may vary between rating software programs.
Units Data structure: opening
Input Restrictions There are no restrictions, other than a match with the construction drawings or as-built drawings. Specification of the fenestration position within its parent surface is required for the following conditions: 1) exterior shading is modeled from buildings, vegetation, other objects; or 2) if daylighting is modeled within the adjacent space.
Baseline Rules

The geometry of the fenestration shall be identical to the proposed design with the following exceptions:

  • If the gross area of all windows in the building exceeds 40% of the gross above-grade exterior wall area in the building, the dimensions of each window in the baseline building shall be reduced in size such that the window area in the baseline building is equal to 40% of the above-grade exterior wall area.
  • If the gross area of skylights in the building exceeds 5% of the gross roof area, the dimensions of each skylight shall be reduced in size such that the skylight area in the proposed design is equal to 5% of the gross roof area.
Fenestration Construction
Applicability All fenestration
Definition A collection of values that together describe the performance of a fenestration system. The values that are used to specify the criteria are U-factor, SHGC and VT . Data may be specified in other ways, however, as long as the data are supported by appropriate tests.
Units Data structure: fenestration construction
Input Restrictions Performance information for fenestration shall be developed from NFRC test procedures or shall be taken from the default values in Appendix A of the baseline standard. Values entered shall be consistent with the specifications and the construction documents.
Baseline Rules The requirements for vertical fenestration U factor, Solar Heat Gain Coefficient, and Visible light transmission by climate zone and framing type are found in [bookref id="baseline-building-criteria-for-vertical-glazing-for- 90.1-2007"] and for skylight inputs in [bookref id="Baseline Building Criteria for Skylights" id="baseline-building-criteria-for-skylights"]. In cases where there is no requirement (NR) for SHGC or VT, the baseline building shall be equal to the proposed design.

[table title="Baseline Building Criteria for Vertical Glazing for 90.1 2007 and 90.1-2010" id="baseline-building-criteria-for-vertical-glazing-for- 90.1-2007"]

Building type Fenestration Type Climate Zone Standard Design
U-factor SHGC VT
Nonresidential Non-Metal Framing 1 1.20 0.25 0.32
2 0.75 0.25 0.32
3 0.65 0.25 0.32
4 0.40 0.40 0.51
5,6 0.35 0.40 0.51
7,8 0.35 0.45 0.57
Metal Framing
Curtainwall/ Storefront		 1 1.20 0.25 0.32
2 0.70 0.25 0.32
3 0.60 0.25 0.32
4 0.50 0.40 0.51
5,6 0.45 0.40 0.51
7,8 0.40 0.45 0.57
Metal Framing
Entrance Door		 1 1.20 0.25 0.32
2 1.10 0.25 0.32
3 0.90 0.25 0.32
4 0.85 0.40 0.51
5,6 0.80 0.40 0.51
7,8 0.80 0.45 0.57
Nonresidential (Continued) Metal Framing
All Other		 1 1.20 0.25 0.32
2 0.75 0.25 0.32
3 0.65 0.25 0.32
4 0.55 0.40 0.51
5,6 0.55 0.40 0.51
7,8 0.45 0.45 0.57
Residential Non-Metal Framing 1 1.20 0.25 0.32
2 0.75 0.25 0.32
3 0.65 0.25 0.32
4 0.40 0.40 0.51
5,6 0.35 0.40 0.51
7,8 0.35 NR NR
Metal Framing
Curtainwall/ Storefront		 1 1.20 0.25 0.32
2 0.70 0.25 0.32
3 0.60 0.25 0.32
4 0.50 0.40 0.51
5,6 0.45 0.40 0.51
7,8 0.40 NR NR
Metal Framing
Entrance Door		 1 1.20 0.25 0.32
2 1.10 0.25 0.32
3 0.90 0.25 0.32
4 0.85 0.40 0.51
5,6 0.80 0.40 0.51
7,8 0.80 NR NR
Metal Framing
All Other		 1 1.20 0.25 0.32
2 0.75 0.25 0.32
3 0.65 0.25 0.32
4 0.55 0.40 0.51
5,6 0.55 0.40 0.51
7,8 0.45 NR NR
Residential Non-Metal Framing 1- 5 1.20 NR NR
6- 8 0.65 NR NR
Metal Framing
Curtainwall/ Storefront		 1- 5 1.20 NR NR
6- 8 0.60 NR NR
Metal Framing
Entrance Door		 1- 5 1.20 NR NR
6- 8 0.90 NR NR
Residential (Continued) Metal Framing
All Other		 1- 5 1.20 NR NR
6- 8 0.65 NR NR

Applicable to all window to wall ratios (0-40.0%)

[table title="Baseline Building Criteria for Skylights" id="baseline-building-criteria-for-skylights"]

Proposed Design Applicable Standard Climate Zone % of Roof Standard Design
U-factor SHGC VT
Glass Skylight with Curb 90.1 – 2001
&
90.1 - 2007		 1,2 0-2.0% 1.98 0.36 0.46
2.1-5.0% 1.98 0.19 0.24
3 (A,B) - (all climate zone 3 for 2007) 0-2.0% 1.17 0.39 0.50
2.1-5.0% 1.17 0.19 0.24
3 (C)
(2001 only)		 0-2.0% 1.98 0.61 0.77
2.1-5.0% 1.98 0.39 0.50
4,5 0-2.0% 1.17 0.49 0.62
2.1-5.0% 1.17 0.39 0.50
6 0-5.0% 1.17 0.49 0.62
7 0-2.0% 1.17 0.68 0.68
2.1-5.0% 1.17 0.64 0.64
8 0-2.0% 0.98 0.55 0.63
Plastic Skylight with Curb 90.1 - 2001
&
90.1 - 2007		 1 0-2.0% 1.90 0.34 0.41
2.1-5.0% 1.90 0.27 0.32
2 0-2.0% 1.90 0.39 0.47
2.1-5.0% 1.90 0.34 0.41
3,4 0-2.0% 1.30 0.65 0.78
2.1-5.0% 1.30 0.34 0.41
5 0-2.0% 1.10 0.77 0.92
2.1-5.0% 1.10 0.62 0.74
6 0-2.0% 0.87 0.71 0.85
2.1-5.0% 0.87 0.58 0.70
7 0-2.0% 0.87 0.77 0.92
2.1-5.0% 0.87 0.71 0.85
8 0-2.0% 0.61 0.59 0.64
Skylight without Curb 90.1 – 2001
&
90.1 – 2007		 1,2 0-2.0% 1.36 0.36 0.46
2.1-5.0% 1.36 0.19 0.24
3 (A,B) - (all climate zone 3 for 2007) 0-2.0% 0.69 0.39 0.50
2.1-5.0% 0.69 0.19 0.24
3 (C)
(2001 only)		 0-2.0% 1.36 0.61 0.77
2.1-5.0% 1.36 0.39 0.50
4,5 0-2.0% 0.69 0.49 0.62
2.1-5.0% 0.69 0.39 0.50
6 0-5.0% 0.69 0.49 0.62
7 0-2.0% 0.69 0.68 0.68
2.1-5.0% 0.69 0.64 0.64
8 0-5.0% 0.58 0.55 0.63
External Shading Devices
Applicability All fenestration
Definition Devices or building features, such as overhangs, fins, shading screens, and setbacks of windows from the exterior face of the wall, that are documented on the construction documents and shade the glazing. Objects that shade the building but that are not part of the building and parts of the building that cause the building to shade itself are also modeled, but are not a part of this building descriptor. See Shading of the Building Site.
Units Data structure: opening shade
Input Restrictions No restrictions other than that the inputs must match the construction documents
Baseline Rules The baseline building is modeled without external shading devices.
Internal Shading Devices
Applicability All fenestration
Definition Curtains, blinds, louvers, or other devices that are applied on the room side of the glazing material. Glazing systems that use blinds between the glazing layers are also considered internal shading devices. Glass coatings or components or treatments of the glazing materials are addressed through the Fenestration Construction building descriptor.
Units Data structure
Input Restrictions Internal shading shall not be modeled in the proposed design, unless it is automatically controlled, based on input from an astronomical timeclock, an exterior pyronometer, or other sensors. The control algorithm shall be documented on the construction documents. Interior shades without automatic controls shall not be modeled.
Baseline Rules The baseline building shall be modeled without interior shades.

Note that fenestration includes windows, doors that have more than 50% glazed area, and skylights. A skylight is fenestration that has a tilt of less than 60° from horizontal.

Fenestration Name
Applicability All fenestration, optional input
Definition A unique name or code that relates the fenestration to the design documents and a parent surface.
Units Text, unique
Input Restrictions No restrictions
Baseline Rules Not applicable
Fenestration Type (Vertical Fenestration)
Applicability All vertical fenestration
Definition This is a classification of vertical fenestration that determines the thermal performance and solar performance requirement for vertical fenestration.
Units

List (ASHRAE Standard 90.1-2007): Nonmetal framing (all); metal framing (curtainwall/storefront); metal framing (entrance door); or metal framing (all other)
Input Restrictions No restrictions, other than that the vertical fenestration type must agree with the type specified on the construction documents or the as-built drawings.
Baseline Rules Same as the proposed design
Fenestration Type (Skylights)
Applicability All skylights
Definition This is a classification of skylights that determines the thermal performance and solar performance requirement for vertical fenestration.
Units List: Glass skylight with curb; plastic skylight with curb; or skylights with no curb
Input Restrictions No restrictions, other than the skylight types specified must agree with the construction documents or the as-built drawings.
Baseline Rules Same as the proposed design
Fenestration Geometry
Applicability All fenestration
Definition Fenestration geometry defines the position and dimensions of the fenestration surface within its parent surface and the identification of the parent surface. The orientation and tilt is inherited from the parent surface. The details of how the coordinate system is implemented may vary between rating software programs.
Units Data structure: opening
Input Restrictions There are no restrictions, other than a match with the construction drawings or as-built drawings. Specification of the fenestration position within its parent surface is required for the following conditions: 1) exterior shading is modeled from buildings, vegetation, other objects; or 2) if daylighting is modeled within the adjacent space.
Baseline Rules

The geometry of the fenestration shall be identical to the proposed design with the following exceptions:

  • If the gross area of all windows in the building exceeds 40% of the gross above-grade exterior wall area in the building, the dimensions of each window in the baseline building shall be reduced in size such that the window area in the baseline building is equal to 40% of the above-grade exterior wall area.
  • If the gross area of skylights in the building exceeds 5% of the gross roof area, the dimensions of each skylight shall be reduced in size such that the skylight area in the proposed design is equal to 5% of the gross roof area.
Fenestration Construction
Applicability All fenestration
Definition A collection of values that together describe the performance of a fenestration system. The values that are used to specify the criteria are U-factor, SHGC and VT . Data may be specified in other ways, however, as long as the data are supported by appropriate tests.
Units Data structure: fenestration construction
Input Restrictions Performance information for fenestration shall be developed from NFRC test procedures or shall be taken from the default values in Appendix A of the baseline standard. Values entered shall be consistent with the specifications and the construction documents.
Baseline Rules The requirements for vertical fenestration U factor, Solar Heat Gain Coefficient, and Visible light transmission by climate zone and framing type are found in Table 6.5.7-1 and for skylight inputs in Table 6.5.7-2. In cases where there is no requirement (NR) for SHGC or VT, the baseline building shall be equal to the proposed design.

Table 6.5.7-1: Baseline Building Criteria for Vertical Glazing for 90.1 2007 and 90.1-2010

Building type Fenestration Type Climate Zone Standard Design
U-factor SHGC VT
Nonresidential Non-Metal Framing 1 1.20 0.25 0.32
2 0.75 0.25 0.32
3 0.65 0.25 0.32
4 0.40 0.40 0.51
5,6 0.35 0.40 0.51
7,8 0.35 0.45 0.57
Metal Framing
Curtainwall/ Storefront		 1 1.20 0.25 0.32
2 0.70 0.25 0.32
3 0.60 0.25 0.32
4 0.50 0.40 0.51
5,6 0.45 0.40 0.51
7,8 0.40 0.45 0.57
Metal Framing
Entrance Door		 1 1.20 0.25 0.32
2 1.10 0.25 0.32
3 0.90 0.25 0.32
4 0.85 0.40 0.51
5,6 0.80 0.40 0.51
7,8 0.80 0.45 0.57
Nonresidential (Continued) Metal Framing
All Other		 1 1.20 0.25 0.32
2 0.75 0.25 0.32
3 0.65 0.25 0.32
4 0.55 0.40 0.51
5,6 0.55 0.40 0.51
7,8 0.45 0.45 0.57
Residential Non-Metal Framing 1 1.20 0.25 0.32
2 0.75 0.25 0.32
3 0.65 0.25 0.32
4 0.40 0.40 0.51
5,6 0.35 0.40 0.51
7,8 0.35 NR NR
Metal Framing
Curtainwall/ Storefront		 1 1.20 0.25 0.32
2 0.70 0.25 0.32
3 0.60 0.25 0.32
4 0.50 0.40 0.51
5,6 0.45 0.40 0.51
7,8 0.40 NR NR
Metal Framing
Entrance Door		 1 1.20 0.25 0.32
2 1.10 0.25 0.32
3 0.90 0.25 0.32
4 0.85 0.40 0.51
5,6 0.80 0.40 0.51
7,8 0.80 NR NR
Metal Framing
All Other		 1 1.20 0.25 0.32
2 0.75 0.25 0.32
3 0.65 0.25 0.32
4 0.55 0.40 0.51
5,6 0.55 0.40 0.51
7,8 0.45 NR NR
Residential Non-Metal Framing 1- 5 1.20 NR NR
6- 8 0.65 NR NR
Metal Framing
Curtainwall/ Storefront		 1- 5 1.20 NR NR
6- 8 0.60 NR NR
Metal Framing
Entrance Door		 1- 5 1.20 NR NR
6- 8 0.90 NR NR
Residential (Continued) Metal Framing
All Other		 1- 5 1.20 NR NR
6- 8 0.65 NR NR

Applicable to all window to wall ratios (0-40.0%)

Table 6.5.7-2: Baseline Building Criteria for Skylights

Proposed Design Applicable Standard Climate Zone % of Roof Standard Design
U-factor SHGC VT
Glass Skylight with Curb 90.1 – 2001
&
90.1 - 2007		 1,2 0-2.0% 1.98 0.36 0.46
2.1-5.0% 1.98 0.19 0.24
3 (A,B) - (all climate zone 3 for 2007) 0-2.0% 1.17 0.39 0.50
2.1-5.0% 1.17 0.19 0.24
3 (C)
(2001 only)		 0-2.0% 1.98 0.61 0.77
2.1-5.0% 1.98 0.39 0.50
4,5 0-2.0% 1.17 0.49 0.62
2.1-5.0% 1.17 0.39 0.50
6 0-5.0% 1.17 0.49 0.62
7 0-2.0% 1.17 0.68 0.68
2.1-5.0% 1.17 0.64 0.64
8 0-2.0% 0.98 0.55 0.63
Plastic Skylight with Curb 90.1 - 2001
&
90.1 - 2007		 1 0-2.0% 1.90 0.34 0.41
2.1-5.0% 1.90 0.27 0.32
2 0-2.0% 1.90 0.39 0.47
2.1-5.0% 1.90 0.34 0.41
3,4 0-2.0% 1.30 0.65 0.78
2.1-5.0% 1.30 0.34 0.41
5 0-2.0% 1.10 0.77 0.92
2.1-5.0% 1.10 0.62 0.74
6 0-2.0% 0.87 0.71 0.85
2.1-5.0% 0.87 0.58 0.70
7 0-2.0% 0.87 0.77 0.92
2.1-5.0% 0.87 0.71 0.85
8 0-2.0% 0.61 0.59 0.64
Skylight without Curb 90.1 – 2001
&
90.1 – 2007		 1,2 0-2.0% 1.36 0.36 0.46
2.1-5.0% 1.36 0.19 0.24
3 (A,B) - (all climate zone 3 for 2007) 0-2.0% 0.69 0.39 0.50
2.1-5.0% 0.69 0.19 0.24
3 (C)
(2001 only)		 0-2.0% 1.36 0.61 0.77
2.1-5.0% 1.36 0.39 0.50
4,5 0-2.0% 0.69 0.49 0.62
2.1-5.0% 0.69 0.39 0.50
6 0-5.0% 0.69 0.49 0.62
7 0-2.0% 0.69 0.68 0.68
2.1-5.0% 0.69 0.64 0.64
8 0-5.0% 0.58 0.55 0.63
External Shading Devices
Applicability All fenestration
Definition Devices or building features, such as overhangs, fins, shading screens, and setbacks of windows from the exterior face of the wall, that are documented on the construction documents and shade the glazing. Objects that shade the building but that are not part of the building and parts of the building that cause the building to shade itself are also modeled, but are not a part of this building descriptor. See Shading of the Building Site.
Units Data structure: opening shade
Input Restrictions No restrictions other than that the inputs must match the construction documents
Baseline Rules The baseline building is modeled without external shading devices.
Internal Shading Devices
Applicability All fenestration
Definition Curtains, blinds, louvers, or other devices that are applied on the room side of the glazing material. Glazing systems that use blinds between the glazing layers are also considered internal shading devices. Glass coatings or components or treatments of the glazing materials are addressed through the Fenestration Construction building descriptor.
Units Data structure
Input Restrictions Internal shading shall not be modeled in the proposed design, unless it is automatically controlled, based on input from an astronomical timeclock, an exterior pyronometer, or other sensors. The control algorithm shall be documented on the construction documents. Interior shades without automatic controls shall not be modeled.
Baseline Rules The baseline building shall be modeled without interior shades.

Note that fenestration includes windows, doors that have more than 50% glazed area, and skylights. A skylight is fenestration that has a tilt of less than 60° from horizontal.

Fenestration Name

Applicability

All fenestration, optional input

Definition

A unique name or code that relates the fenestration to the design documents and a parent surface.

Units

Text, unique

Input Restrictions

No restrictions

Baseline Rules

Not applicable

 

Fenestration Type (Vertical Fenestration)

Applicability

All vertical fenestration, optional input

Definition

This is a classification of vertical fenestration that determines the prescriptive thermal performance and solar performance requirement for vertical fenestration. It is not used for performance calculations.

Units

List (ASHRAE Standard 90.1-2013): Nonmetal framing (all); metal framing (curtainwall/storefront); metal framing (entrance door); or metal framing (all other)

Input Restrictions

No restrictions, other than that the vertical fenestration type must agree with the type specified on the construction documents or the as-built drawings.

Baseline Rules

The performance of the baseline building fenestration is specified independent of this input.

 

Fenestration Type (Skylights)

Applicability

All skylights, optional input

Definition

This is a classification of skylights that determines the prescriptive thermal performance and solar performance requirement for skylights. It is not used for performance calculations.

Units

List: Glass skylight with curb; plastic skylight with curb; or skylights with no curb

Input Restrictions

No restrictions, other than the skylight types specified must agree with the construction documents or the as-built drawings.

Baseline Rules

Skylights in the baseline building are specified independent of this input. All skylights in the baseline building are assumed to be “skylights with no curb”.

 

Vertical Fenestration Geometry

Applicability

All vertical fenestration

Definition

Fenestration geometry defines the position and dimensions of the fenestration surface within its parent surface and the identification of the parent surface. The orientation and tilt is inherited from the parent surface. The details of how the coordinate system is implemented may vary between rating software programs.

Units

Data structure: opening

Input Restrictions

There are no restrictions, other than a match with the construction drawings or as-built drawings. Specification of the fenestration position within its parent surface is required for the following conditions: 1) exterior shading is modeled from buildings, vegetation, other objects; or 2) if daylighting is modeled within the adjacent space.

Baseline Rules

The geometry of the vertical fenestration shall be similar to the proposed design but each fenestration shall be increased or reduced in size in proportion to the proposed design size such that the overall fenestration area as a percentage of the above-grade exterior wall area is equal to the values in Table 3.5.7x.

Table 3.5.7-1: Baseline Building Vertical Fenestration Area

Building Area Typesa

Baseline Building Gross Above-Grade-Wall Area

Grocery Store

7%

Healthcare (outpatient)

21%

Hospital

27%

Hotel/motel (≤75 rooms)

24%

Hotel/motel (>75 rooms)

34%

Office (≤5000 ft2)

19%

Office (5000 to 50,000 ft2)

31%

Office (>50,000 ft2)

40%

Restaurant (quick service)

34%

Restaurant (full service)

24%

Retail (stand alone)

11%

Retail (strip mall)

20%

School (primary)

22%

School (secondary and university)

22%

Warehouse (nonrefrigerated)

6%

a. In cases where both a general building area type and a specific building area type are listed, the specific building area type shall apply.

 

Horizontal Fenestration (Skylight) Geometry

Applicability

All horizontal fenestration (skylights)

Definition

Fenestration geometry defines the position and dimensions of the fenestration surface within its parent surface and the identification of the parent surface. The orientation and tilt is inherited from the parent surface. The details of how the coordinate system is implemented may vary between rating software programs.

Units

Data structure: opening

Input Restrictions

There are no restrictions, other than a match with the construction drawings or as-built drawings. Specification of the fenestration position within its parent surface is required for the following conditions: 1) exterior shading is modeled from buildings, vegetation, other objects; or 2) if daylighting is modeled within the adjacent space.

Baseline Rules

The geometry of the vertical fenestration shall be equal to the proposed design unless the gross area of skylights in the building exceeds 5% of the gross roof area. When this case exists, the dimensions of each skylight shall be reduced in size such that the skylight area in the proposed design is equal to 5% of the gross roof area.

 

 

 

Fenestration Construction

Applicability

All fenestration

Definition

A collection of values that together describe the performance of a fenestration system. The values that are used to specify the criteria are U-factor, SHGC and VT . Data may be specified in other ways, however, as long as the data are supported by appropriate tests.

Units

Data structure: fenestration construction

Input Restrictions

Performance information for fenestration shall be developed from NFRC test procedures or shall be taken from the default values in Appendix A of the baseline standard. Values entered shall be consistent with the specifications and the construction documents.

Dynamic glazing shall be modeled in the proposed design. If the dynamic is controlled automatically, the modeled value of SHGC and VT shall be the average of the minimum and maximum values.

Baseline Rules

The requirements for vertical fenestration U factor, Solar Heat Gain Coefficient, and Visible light transmission by climate zone are found in Table 3.5.7-1 and for skylight inputs in Table 3.5.7-2. In cases where there is no requirement (NR) for SHGC or VT, the baseline building shall be modeled with an SHGC of 0.40 for all vertical fenestration and 0.55 for skylights. VT is not relevant for the baseline building since daylighting is not modeled.

 

Table 3.5.7-2: U-factor Criteria for Vertical and Horizontal Fenestration

Climate Zone

Nonresidential

Residential

Semi-Heated

Vertical

Horizontal

Vertical

Horizontal

Vertical

Horizontal

1

1.22

1.36

1.22

1.36

1.22

1.36

2

3

0.57

0.69

0.57

0.69

4

5

6

0.58 

7

0.69

8

0.46

0.58

0.46

0.58

0.81

Table 3.5.7-3: SHGC Criteria for Vertical Fenestration

Climate Zone

Nonresidential

Residential

Semi-Heated

0-10%

10.1-20%

20.1-30%

30.1-40%

0-10%

10.1-20%

20.1-30%

30.1-40%

0-10%

1

0.25

0.25

0.25

0.25

0.25

0.25

0.25

0.25

NR

2

0.39

NR

3

0.39

0.39

NR

4

0.39

0.39

0.39

0.39

0.39

NR

5

0.49

0.49

NR

6

NR

7

0.49

0.49

0.49

0.49

0.49

0.49

NR

8

NR

NR

NR

NR

NR

NR

NR

NR

NR

Table 3.5.7-4: SHGC Criteria for Horizontal Fenestration

Climate Zone

Nonresidential

Residential

Semi-Heated

0-2%

2.1-5%

0-2%

2.1-5%

0-2%

2.1-5%

1

0.36

0.19

0.19

0.19

NR

NR

2

3

0.39

0.36

4

0.49

0.39

5

0.49

0.49

6

0.49

7

0.68

0.64

0.64

0.64

8

NR

NR

NR

NR

 

 

External Shading Devices

Applicability

All fenestration

Definition

Devices or building features, such as overhangs, fins, shading screens, and setbacks of windows from the exterior face of the wall, that are documented on the construction documents and shade the glazing. Objects that shade the building but that are not part of the building and parts of the building that cause the building to shade itself are also modeled, but are not a part of this building descriptor. See Shading of the Building Site.

Units

Data structure: opening shade

Input Restrictions

No restrictions other than that the inputs must match the construction documents

Baseline Rules

The baseline building is modeled without external shading devices.

 

Internal Shading Devices

Applicability

All fenestration

Definition

Curtains, blinds, louvers, or other devices that are applied on the room side of the glazing material. Glazing systems that use blinds between the glazing layers are also considered internal shading devices. Glass coatings or components or treatments of the glazing materials are addressed through the Fenestration Construction building descriptor.

Units

Data structure

Input Restrictions

Manually operated interior shading devices may or may not be modeled in the proposed design, at the discretion of the energy modeler. Shading devices that are automatically controlled, based on input from an astronomical timeclock, an exterior pyronometer, or other sensors, shall be modeled. The control algorithm shall be documented on the construction documents.

Baseline Rules

If manually operated interior shading devices are modeled in the proposed design, they shall be modeled in a similar manner in the baseline building.

The baseline building shall be modeled without interior shades.

3.5.7 Doors

Door Name

Applicability

All exterior doors, optional input

Definition

A unique name or code that relates the door to the design documents submitted. Doors that are more than 50% glass are treated as windows and must be determined and entered by using the fenestration building descriptors.

Units

Text: unique

Input Restrictions

None

Baseline Building

None

 

Door Type

Applicability

All exterior doors, required input

Definition

For the purposes of determining building envelope requirements, the classifications are defined as follows:

  1. Non-swinging: roll-up, metal coiling, sliding, and all other doors that are not swinging doors.
  2. Swinging: all operable opaque panels with hinges on one side and opaque revolving doors. The prescriptive U-factor requirements depend on door type and climate. This building descriptor may be derived from other building descriptors, in which case a specific input is not necessary.

Units

List: Swinging or Non-swinging

Input Restrictions

The door type shall be consistent with the type of door represented on the construction documents or as-built drawings

Baseline Building

The baseline building door type shall be the same as the proposed design

 

Door Geometry

Applicability

All exterior doors

Definition

Door geometry defines the position and dimensions of the door surface relative to its parent wall surface. The azimuth and tilt (if any) of the door are inherited from the parent surface. The position of the door within the parent surface is specified through X,Y coordinates. The size is specified as a height and width (all doors are generally assumed to be rectangular). The details of how the geometry of doors is specified may vary for each energy simulation program.

Units

Data structure: opening

Input Restrictions

As designed

Baseline Building

Door geometry in the baseline building is identical to the proposed design

 

Door U-factor

Applicability

All exterior doors

Definition

The thermal transmittance of the door, including the frame

Units

Btu/h·ft2·°F

Input Restrictions

Door U-factors shall be taken from the default values in Appendix A of Standard 90.1-2019 or shall be obtained from National Fenestration Rating Council (NFRC) test procedures

Baseline Building

For new construction, the U-factor required for door construction is defined in Table 27

Table 27. Standard 90.1-2019 Requirements for Doors for Baseline Building

Swinging or

Non-swinging

Climate Zone

Space Conditioning Category

Nonresidential

U-Value

Residential

U-Value

Semi-Heated

U-Value

Swinging

 

Climate Zone 0 and 1

0.7

0.7

0.7

Climate Zone 2

0.7

0.7

0.7

Climate Zone 3

0.7

0.7

0.7

Climate Zone 4

0.7

0.7

0.7

Climate Zone 5

0.7

0.7

0.7

Climate Zone 6

0.7

0.5

0.7

Climate Zone 7

0.7

0.5

0.7

Climate Zone 8

0.5

0.5

0.7

Non-swinging

Climate Zone 0 and 1

1.45

1.45

1.45

Climate Zone 2

1.45

1.45

1.45

Climate Zone 3

1.45

0.5

1.45

Climate Zone 4

1.45

0.5

1.45

Climate Zone 5

1.45

0.5

1.45

Climate Zone 6

0.5

0.5

1.45

Climate Zone 7

0.5

0.5

1.45

Climate Zone 8

0.5

0.5

1.45

Note that fenestration includes windows, doors that have more than 50% glazed area, and skylights. A skylight is fenestration that has a tilt of less than 60° from horizontal.

Fenestration Name
Applicability All fenestration, optional input
Definition A unique name or code that relates the fenestration to the design documents and a parent surface.
Units Text, unique
Input Restrictions No restrictions
Fenestration Type (Skylights)
Applicability All skylights
Definition This is a classification of skylights that determines the thermal performance and solar performance requirement for vertical fenestration.
Units List: Glass skylight with curb; plastic skylight with curb; or skylights with no curb
Input Restrictions No restrictions, other than the skylight types specified must agree with the construction documents or the as-built drawings.
Fenestration Geometry
Applicability All fenestration
Definition Fenestration geometry defines the position and dimensions of the fenestration surface within its parent surface and the identification of the parent surface. The orientation and tilt is inherited from the parent surface. The details of how the coordinate system is implemented may vary between rating software programs.
Units Data structure: opening
Input Restrictions There are no restrictions, other than a match with the construction drawings or as-built drawings. Specification of the fenestration position within its parent surface is required for the following conditions: 1) exterior shading is modeled from buildings, vegetation, other objects; or 2) if daylighting is modeled within the adjacent space.
Fenestration Construction
Applicability All fenestration
Definition A collection of values that together describe the performance of a fenestration system. The values that are used to specify the criteria are U-factor, SHGC and VT . Data may be specified in other ways, however, as long as the data are supported by appropriate tests.
Units Data structure: fenestration construction
Input Restrictions Performance information for fenestration shall be developed from NFRC test procedures or shall be taken from the default values in Appendix A of the baseline standard. Values entered shall be consistent with the specifications and the construction documents.

 

External Shading Devices
Applicability All fenestration
Definition Devices or building features, such as overhangs, fins, shading screens, and setbacks of windows from the exterior face of the wall, that are documented on the construction documents and shade the glazing. Objects that shade the building but that are not part of the building and parts of the building that cause the building to shade itself are also modeled, but are not a part of this building descriptor. See Shading of the Building Site.
Units Data structure: opening shade
Input Restrictions No restrictions other than that the inputs must match the construction documents
Internal Shading Devices
Applicability All fenestration
Definition Curtains, blinds, louvers, or other devices that are applied on the room side of the glazing material. Glazing systems that use blinds between the glazing layers are also considered internal shading devices. Glass coatings or components or treatments of the glazing materials are addressed through the Fenestration Construction building descriptor.
Units Data structure
Input Restrictions Internal shading shall not be modeled in the proposed design, unless it is automatically controlled, based on input from an astronomical timeclock, an exterior pyronometer, or other sensors. The control algorithm shall be documented on the construction documents. Interior shades without automatic controls shall not be modeled.

Note that fenestration includes windows, doors that have more than 50% glazed area, and skylights. A skylight is fenestration that has a tilt of less than 60° from horizontal.

Fenestration Name
Applicability All fenestration, optional input
Definition A unique name or code that relates the fenestration to the design documents and a parent surface.
Units Text, unique
Input Restrictions No restrictions
Fenestration Type (Skylights)
Applicability All skylights
Definition This is a classification of skylights that determines the thermal performance and solar performance requirement for vertical fenestration.
Units List: Glass skylight with curb; plastic skylight with curb; or skylights with no curb
Input Restrictions No restrictions, other than the skylight types specified must agree with the construction documents or the as-built drawings.
Fenestration Geometry
Applicability All fenestration
Definition Fenestration geometry defines the position and dimensions of the fenestration surface within its parent surface and the identification of the parent surface. The orientation and tilt is inherited from the parent surface. The details of how the coordinate system is implemented may vary between rating software programs.
Units Data structure: opening
Input Restrictions There are no restrictions, other than a match with the construction drawings or as-built drawings. Specification of the fenestration position within its parent surface is required for the following conditions: 1) exterior shading is modeled from buildings, vegetation, other objects; or 2) if daylighting is modeled within the adjacent space.
Fenestration Construction
Applicability All fenestration
Definition A collection of values that together describe the performance of a fenestration system. The values that are used to specify the criteria are U-factor, SHGC and VT . Data may be specified in other ways, however, as long as the data are supported by appropriate tests.
Units Data structure: fenestration construction
Input Restrictions Performance information for fenestration shall be developed from NFRC test procedures or shall be taken from the default values in Appendix A of the baseline standard. Values entered shall be consistent with the specifications and the construction documents.

 

External Shading Devices
Applicability All fenestration
Definition Devices or building features, such as overhangs, fins, shading screens, and setbacks of windows from the exterior face of the wall, that are documented on the construction documents and shade the glazing. Objects that shade the building but that are not part of the building and parts of the building that cause the building to shade itself are also modeled, but are not a part of this building descriptor. See Shading of the Building Site.
Units Data structure: opening shade
Input Restrictions No restrictions other than that the inputs must match the construction documents
Internal Shading Devices
Applicability All fenestration
Definition Curtains, blinds, louvers, or other devices that are applied on the room side of the glazing material. Glazing systems that use blinds between the glazing layers are also considered internal shading devices. Glass coatings or components or treatments of the glazing materials are addressed through the Fenestration Construction building descriptor.
Units Data structure
Input Restrictions Internal shading shall not be modeled in the proposed design, unless it is automatically controlled, based on input from an astronomical timeclock, an exterior pyronometer, or other sensors. The control algorithm shall be documented on the construction documents. Interior shades without automatic controls shall not be modeled.