If you have decided your windows need better locks — whether for security, for an insurance requirement, or for child safety — the next question is the practical one: what do you actually buy, and for which window? The honest answer is that it depends entirely on the type of window you have, and fitting the wrong device is a common and avoidable waste of money. This is a plain buyer’s guide to choosing and upgrading window locks: what suits each window, what to specify, and what it should cost.
If you first want to understand why windows are a weak point and how each lock resists attack, start with our window security guide. This guide picks up where that leaves off — at the buying decision.
This is the whole game. The right device depends on how your window opens:
Whatever the window, the feature that matters most is that it is key-operated. A key lock resists forcing, acts as a visible deterrent, and — the part people miss — is what most home insurers require on accessible windows as a condition of cover. A non-locking catch may be convenient, but for security and for your policy it barely counts. When you are buying, “key-locking” is the words to look for.
Cheap is a false economy here, because a lock is only as strong as its weakest fixing. When choosing, look for: a recognised standard such as BS3621 on the lock, or windows tested to PAS 24 if you are replacing the whole unit; solid construction (brass or steel rather than thin zinc-alloy castings on the load-bearing parts); and multiple locking points rather than a single bolt, since one point can be levered. Trusted hardware brands — the likes of Yale, Mila and Jackloc — are a reasonable shorthand for quality.
Never lock or restrict every window so completely that no one can escape a fire. Keep at least one easily-openable window in each room as an escape route, and make sure the whole household knows where the keys are.
If you are upgrading several windows, ask for them to be keyed alike where possible, so one key fits the lot — far more practical than a drawer of near-identical keys. It is usually achievable when the locks are the same type, and it makes the “keep the keys accessible for escape” rule much easier to live with.
Window locks are among the cheapest security upgrades there is. The hardware itself is modest — a key-locking handle, casement lock or restrictor is typically a low-double-figures part — so the main variable is whether you fit it yourself or have it done. A locksmith fitting locks across a house is usually a short, inexpensive visit, and far cheaper than the replacement windows a glazing company might steer you toward for a fault that is really just the lock.
A named, vetted master locksmith covers your area — no call-out fee.
Confident DIYers can fit surface-mounted casement locks and restrictors, and swapping a like-for-like espag handle is achievable — the catch is matching the replacement exactly for length, backset and faceplate, which is where home jobs most often stall. Where it matters is the security-critical accessible windows and anything your insurer specifies: there, having them fitted correctly to the right standard is cheap insurance against a lock that looks fitted but does not actually protect you. If in doubt, a locksmith can survey what you have, tell you honestly what each window needs, and fit the right locks in one visit.
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