Windows and Doors

Windows and doors are openings in the building envelope that affect both transmission heat transfer and solar heat gain.

Adding Windows

Quick Add

1. Select an exterior wall segment
2. Click Add Window
3. Enter the total window area or count and size
4. Assign a window type

Detailed Entry

For precise modeling:

1. Specify individual window dimensions
2. Enter the sill height above floor
3. Position windows along the wall

Window Properties

Dimensions

• Width - Horizontal dimension
• Height - Vertical dimension
• Sill Height - Distance from floor to bottom of window

Window Type

Links to the window type definition. Determines:

• U-value for transmission heat transfer
• SHGC (Solar Heat Gain Coefficient)
• Visible Transmittance

Count

Number of identical windows on this wall segment.

Solar Heat Gain

Windows are the primary source of solar heat gain. The calculation considers:

SHGC (Solar Heat Gain Coefficient)

The fraction of solar radiation that enters through the window:

• Values range from 0.2 to 0.8
• Lower SHGC means less solar gain
• Affects cooling loads significantly

Orientation

Solar gain varies by wall orientation:

• South - Highest gain in winter, moderate in summer
• West - High afternoon gain in summer
• East - Morning gain
• North - Lowest direct solar gain

Shading

External shading reduces solar gain:

• Overhangs and fins
• External blinds or screens
• Adjacent building shadows

Adding Doors

Door Entry

1. Select an exterior wall segment
2. Click Add Door
3. Enter door dimensions
4. Assign a door type

Door Properties

• Width and Height
• Door Type - Solid, glass, or combination
• U-value - Heat transfer coefficient

Glazed Doors

For doors with significant glazing:

• Use a door type that includes SHGC
• Or add as a window at floor level
• Consider traffic-related infiltration

Interior Windows

Windows between interior spaces:

• Transfer grilles and vision panels
• May affect airflow between spaces
• Usually no thermal impact if spaces are conditioned

Skylights

Skylights are windows in the roof:

• See Roof for skylight configuration
• Higher solar gain due to sun angle
• Significant impact on top-floor loads

Best Practices

1. Verify areas - Check that window areas match specifications
2. Use accurate SHGC - This significantly affects cooling loads
3. Consider shading - Account for overhangs and external shading
4. Don’t forget doors - Include exterior doors in the envelope
5. Check orientations - Solar calculations depend on correct orientation