The Counterbalanced Vertical Slider or Sash window is one of the most common windows that we install. The frame on this window is 34 mm high and 37 mm high.
This style of windows allows the top panel to slide down and the bottom panel to slide up working in the same way as your original window. We measure the break line of your original window so that the new window matches the old one exactly.
Counterbalanced vertical sliders are at the top end of the price range because of the complexity in making them and the amount of parts that have to be used.