Windows allow you to let sunlight in, to
look at the outside world and to allow fresh air into your house when they are open. When
closed they help maintain the temperature inside your house. But how much do you really know
about your windows? This tutorial will explain to you the most popular types of windows and
how they work. This insight will help you understand projects and repairs that involve your
We will look at 4 types of windows double-hung windows, casement windows, sliding windows
and awning windows. What differs from one window type to another is how the sash moves to
open the window. In some cases the sash may even be stationary.
The common element
to all of these window types is the sash. A sash is the frame
that surrounds and secures the glass. The sash can be made of wood, metal
or plastic. The sashes are built from 4 frame components, the top and
bottom pieces are called rails and the sides are called stiles. In many
cases a window sash is divided into smaller windows. The dividers are
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windows (Figure 1) have 2 independent sashes that slide past each
other in separate tracks. The upper sash is in the outer track and is closer to the house
exterior. The lower sash is closer to the house interior and is in the inner track.
independent tracks or channels are created by an interior window stop, a parting strip that
separates the 2 sashes and finally an exterior window stop.
windows, the sashes are counter balanced by a weight inside the walls that is attached to the
sash with a cotton cord or chain running over a pulley at the top of the window frame. Each
sash has 2 counter weights one on either side. These cords are prone to breaking over
time due to wear, chafing or paint build-up. See our tutorial on Replacing sash cords to learn
how to remedy this situation. Newer windows use spring-balance mechanisms instead of counter
windows (Figure 2) swing out like a door. Smaller windows use 1
sash. Larger windows have 2 sashes that swing out in opposite directions away from a center
post. Similar to a double-hung window, the sashes are made up of an upper and lower rail and 2
newer casement windows are generally pivot-arm hinges. They allow the hinge edge of the sash
to slide away from the window frame as it opens. This feature helps when it is time to clean
the outside of the window by allowing access between the frame and the sash.
windows are opened via an extension arm at the bottom of the window. Newer windows are operated
by a crank handle which drives a gear mechanism to open the window and hold it in the desired
windows (Figure 3) are probably the simplest type of window. Just
like a double-hung window, a sliding window has 2 sashes that slide past each other. However,
they move in a horizontal direction instead of up and down. This means the sashes do no require
counter balances. They merely slide back and forth in tracks. Generally the outer sash is fixed
in position and the inner sash slides back and forth.
windows(Figure 4) are similar to casement windows except that they
open horizontally instead of vertically. They are hinged at the top 2 corners and open outward.
At the bottom of the window is a crank mechanism with scissor arms that hold the window open
in any desired position.