Hold the back of your hand along the edge of the window frame on a windy evening and move it slowly round the perimeter. Somewhere the air goes cold and alive. Where that happens tells you most of what you need to know, because a draught is not one problem. It is three different problems wearing the same jumper.
Problem one: the window is fine, the seals are not
If the cold air comes from between the opening sash and the frame, on a window that is otherwise sound, you are probably feeling dead gaskets or a dropped hinge. Rubber seals compress and harden over a couple of decades; friction hinges sag until the sash no longer pulls tight. Both are repairs, not replacements. A window repair specialist can re-gasket a whole house of windows and re-tension or replace hinges for a small fraction of what new windows cost, and the improvement on a cold night is immediate. This is the cheapest fix in the whole trade and the least advertised, for the obvious reason that there is more money in selling you windows.
Problem two: the window can never be sealed, but it can be backed up
Old single-glazed sashes and metal-framed windows leak by design, and in a conservation area, or on a listed building, you may not be allowed to replace them with modern units anyway. Secondary glazing is the honourable compromise: a discreet second pane fitted to the inside of the reveal, leaving the original window untouched. Done well it kills draughts, roughly halves heat loss through the window, and is quietly brilliant against traffic noise, which is why hotels on main roads use it. It is also reversible, which is exactly what conservation officers want to hear. Its price is aesthetic: another frame line inside, and a slightly more awkward window to open and clean.
Problem three: the window is simply finished
Sometimes the honest diagnosis is age. Frames that have warped so the sash no longer meets them squarely, uPVC gone chalky and brittle, rot in the sills, misted units and failing hinges arriving together. Repairing a window like that is re-stringing a broken racket. When several faults cluster on the same windows, replacement stops being the expensive option and becomes the only one that stays fixed.
The order to try things in
Work upward from the cheapest credible fix. First the free checks: adjust the locking keeps, check the sash is seated, fit heavy curtains honestly. Then seals and hinges. Then secondary glazing where replacement is barred or the originals deserve keeping. Replacement last, chosen because the diagnosis demands it rather than because a salesman arrived first. A firm that offers repairs as well as installations is well placed to give you a straight verdict, since they earn either way.
Getting a diagnosis rather than a pitch
Describe the symptoms precisely when you contact firms: where the cold air enters, the age of the windows, whether the sash closes tight. The listings on this site include repair specialists and secondary glazing firms alongside installers, so look through companies near you with the right specialism, or set out the symptoms and invite quotes for the fix rather than the full replacement.
Do the back-of-the-hand test tonight and write down exactly where the draughts live. Whoever you call, that list will keep the conversation about your windows instead of their brochure.
