Spiral Balance hung windows are a more contemporary hung window configuration. They are typically less expensive than weight & chain units and do not require the spacing need for weight boxes.
Parrett units also provide concealed spiral balances, as opposed to other manufacturer's visible jamb liners.
Weight & Chain hung windows offer an unrivaled experience for smooth, easy window operation. The largest hung windows are also typically recommended to be manufactured as weight & chain configuration.
Of course, weight & chain windows are required for many historical replication projects.
Triple hung windows are available in weight & chain construction. Aluminum clad triple hung windows are not available from any other manufacturer besides Parrett!
These beautiful windows can serve many functions such as a window that you can actually walk through by employing a "header pocket."