REHAU Windows installed in The Bell Tower building

REHAU 4500 tilt-turn windows

REHAU system 4500 tilt-turn

Bell Tower I Seattle, Washington

The Seattle Housing Authority finds energy-efficient solution that lowers operating costs and improves accessibility for residents


With $3.5 million in funding through the American Recovery and Reinvestment Act, the Seattle Housing Authority looked to identify energy-efficient building solutions for its Bell Tower rehabilitation project. Upgrades to this 118-unit, 17-story high-rise in the heart of Seattle’s Bell town neighborhood included replacement of all windows with REHAU’s highly efficient System 4500 tilt-turn design.

In addition to reducing overall operating costs at the complex, the windows provide a clean, modern look to the building’s exterior, making it more aesthetically welcoming in this trendy area of the city. Residents also enjoy ease of operation, facilitated by the windows’ American Disabilities Act (ADA) hardware features. Those on higher levels of the building additionally appreciate the safety of the tilt-turn design when compared to traditional hung and slider windows.

The System 4500 tilt-turn window design is REHAU's top-of-the line commercial fenestration product offering. This design allows the window to operate in either a tilt or turn position, offering three separate functions in one window: traditional casement look in the turn position, convenient top ventilation in the tilt position, and elegant picture window when closed.

The System 4500 window and door design offers the ultimate in high performance. Its features include:

  • Compression seal sash with two weather seals
  • Multi-point locking hardware
  • Superior sound abatement properties – Ability to build awning and hopper styles with natural ventilation while providing security
  • Ability to reduce heat loss and noise infiltration, providing a warmer, more comfortable living space


Project:Bell Tower, Seattle, WA
Type of construction:Government renovation
Scope of project:370 window elements*
Owner:Seattle Housing Authority
Architect:DKA Architects
Contractor:W.G. Clark Construction Co.
REHAU systems used:System 4500 tilt-turn window

Engineering progress

Enhancing lives