Double hung windows are windows having an upper and lower sash that slide up and down within the sash channel. Single hung windows have a similar appearance except that only the bottom sash moves. The window sashes can become difficult to operate for a variety of reasons, but repairs are often fairly straightforward.
First, lets identify the parts of the window. The window sashes run in the sash channels on the side jambs. The inner channel is between the interior stop and the parting strip, and the outer channel is bounded by the parting strip and the outer stop.
If a window will not open at all, the first thing to check is whether it has been painted shut. Using a razor knife, carefully cut the seam between the stop and the sash along the sides of the window and between the sash and the parting strip. Cut between the sash and the sill or top jamb. If the sash channels were painted score the paint between the sash and side jamb. Now try to move the window. If it still won't budge, then go to the next step.
