What Is the Bar Between Two Windows?
Sometimes what looks like one giant window is actually several separate units joined together.
The connection between those units may involve a:
Mullion.
Pella describes mullions as components used to join windows together into larger combinations.
Why Join Separate Units?
Homeowners may want:
- Larger glass compositions
- Different operating styles together
- Architectural symmetry
For example:
picture window + casement + casement
can create one larger visual opening.
Is a Mullion Just Decorative?
Not always.
The connection may need to transfer:
- Wind loads
- Window weight
- Structural forces
The exact mull system must suit the window sizes and building conditions.
Why Installation Matters
A poorly integrated joint can affect:
- Air sealing
- Water management
- Structural performance
Can Any Two Windows Be Joined?
No.
Manufacturers specify which products and sizes can be combined.
A Window Combination Needs to Work Structurally—not Just Look Balanced.
Envirotech Exteriors can help plan window combinations that fit the opening and the manufacturer’s structural requirements.