The window, part of the robust Metro Series of windows and doors, is a good option for school use as it provides high and low ventilation points for good airflow in classrooms. The two panes move together as in a traditional double-hung format and in the fully open position, the sashes adjoin each other with half the window area open.

The new offering, available from Altherm, First and Vantage window manufacturers, is suitable for residential and commercial applications and will see the current vertical slider system phased out. The Metro Double Hung can be supplied in larger sizes than the previous product because it is a counterweighted system with one sash balancing the other for smooth movement and stability. A 50kg weight restriction per panel applies, with a recommended aspect ratio of 2:1.

The window will feature a control handle mounted on the bottom rail of the inside panel which will drive a two-point espagnolette locking system at the sill. (The previous system was locked at the top rail). Double glazing is standard.