Five common causes, four of which are repairs rather than replacements.
A draught does not automatically mean you need new windows. In many cases the air is coming past a perished gasket, a dropped sash or a gap in the external sealant — all fixable.
Work through these before you get replacement quotes.
Close the window on a sheet of paper. If it pulls out easily at one point, the sash is not compressing the gasket evenly there. Hinge and keep adjustment often solves this in minutes.
Perished external sealant around the frame, cracked pointing and a failed sill drip all let air and water past the frame rather than through the window. These are building repairs, not window faults.
Distorted frames, rotten timber, failed welds and hardware that is no longer manufactured are the points at which repair stops making sense.
We'll tell you honestly — we'd rather fix a hinge than sell you a window you don't need.
On many systems yes, provided the profile is still supported and matching gasket is available.
They can feel draughty in wind, but they serve a ventilation purpose and closing them permanently can cause condensation problems.
Only if the draught is coming through the window. If it's coming past the reveal or a failed sill, that has to be addressed as part of the installation.