Energy & Cost

• Energy
• Peak Demand
• Carbon
• Cost

Human Factors

• Daylighting
• Glare
• View
• Thermal Comfort
• Natural Ventilation

Codes & Standards

• IECC
• ASHRAE 90.1
• ASHRAE 189 & IgCC
• North American Fenestration Standard
• Component Modeling Approach

USEFUL INFORMATION

ASHRAE Standards

2010 | 2007 | 2004

ASHRAE Standard 90.1-2010

ASHRAE Standard 90.1-2010 is the latest version of ASHRAE 90.1. Like all versions of the standard, its prescriptive building envelope option sets U-factor and SHGC requirements and fenestration area limits. Other compliance options allow greater design flexibility but are more complex. Regardless of the chosen compliance option, fenestration must not exceed mandatory air leakage limits.

The prescriptive option limits vertical fenestration area to 40% of the gross above-grade wall area. With exceptions for some buildings, the area of west-oriented and east-oriented vertical fenestration must each not exceed the area of south-oriented vertical fenestration.

The prescriptive option limits skylight area to 5% of the gross roof area. In some larger spaces with high ceilings, the code requires a minimum skylight area for daylighting.

SHGC requirements for vertical fenestration are adjusted where shading from permanent projections is provided. For skylights with plastic and curb, different requirements apply.

Mandatory air leakage limits depend on the fenestration type. For windows, sliding doors, swinging doors and most skylights, the maximum air leakage rate is 0.2 cfm/ft2, or 0.3 cfm/ft2 if tested at 6.24 psf.

2010 | 2007 | 2004

ASHRAE Standard 90.1-2007
ASHRAE Standard 90.1-2007, like all versions of the standard, has a prescriptive building envelope option that sets U-factor and SHGC requirements and fenestration area limits. Other compliance options allow greater design flexibility but are more complex. Regardless of the chosen compliance option, fenestration must not exceed mandatory air leakage limits.

The prescriptive option limits vertical fenestration area to 40% of the gross above-grade wall area and skylight area to 5% of the gross roof area.

SHGC requirements for vertical fenestration are adjusted where shading from permanent projections is provided. For skylights with plastic and curb, different requirements apply.

Mandatory air leakage limits depend on the fenestration type. For windows, sliding doors and skylights, the maximum air leakage rate is 0.4 cfm/ft2.

2010 | 2007 | 2004

ASHRAE Standard 90.1-2004
ASHRAE Standard 90.1-2004, like all versions of the standard, has a prescriptive building envelope option that sets U-factor and SHGC requirements and fenestration area limits. Other compliance options allow greater design flexibility but are more complex. Regardless of the chosen compliance option, fenestration must not exceed mandatory air leakage limits.

The prescriptive option limits vertical fenestration area to 50% of the gross above-grade wall area and skylight area to 5% of the gross roof area.

SHGC requirements for vertical fenestration are adjusted for north-oriented glazing and where shading from permanent projections is provided. For skylights with plastic and curb, different requirements apply.

Mandatory air leakage limits depend on the fenestration type. For windows, sliding doors and skylights, the maximum air leakage rate is 0.4 cfm/ft2.

2010 | 2007 | 2004