A window rattles and draughts
Work from the meeting rail outward to the frame perimeter, because the inner faults are both commoner and cheaper.
- Do the two sashes move against each other at the meeting rail?
That is the commonest single source of both the rattle and the draught, and it is adjustment work rather than replacement.
Repair or replace old sash windows - Does the sash move sideways within the frame?
The parting bead or the staff bead has worn or been replaced too thin. Both are removable and replaceable without touching the sash.
Repair or replace old sash windows - Do the sashes run at all, or are they painted shut?
A seized sash is usually paint or a broken cord, and neither is a reason to consider the window failed.
Repair or replace old sash windows - Is air coming from the sides of the frame rather than around the sashes?
Then it is the pulley pockets or the gap between frame and masonry, which is sealing work at the perimeter.
Weatherstripping a door that still fits - Is the complaint really cold glass rather than moving air?
A cold single-glazed pane produces a downdraught that feels like a leak. A second internal layer addresses that; sealing does not.
Storm windows and interior panels