Cylinder lock, chain lock or smart lock: what's the difference?

The standard cylinder lock: the baseline every door needs

The euro-cylinder is the mechanism inside the door handle that the key actually turns. It's the lock doing the real work of keeping a door shut against someone pushing, kicking or picking it, and it's the one thing every front door has regardless of what else gets added later.

Cylinders vary a good deal in quality. Cheap ones that came with a new-build flat or an older Soviet-era door are often the weakest point in an otherwise solid door, and swapping just the cylinder is one of the most cost-effective security upgrades there is.

A straightforward cylinder replacement, including a mid-range cylinder, typically runs from around 60 € as one of our standard lock replacement jobs. If the door itself, the frame or the strike plate is also worn, that adds to the job, and we'd quote it after a look or photos.

Chain locks and extra bolts: a second obstacle, not the main defence

A chain lock or a small secondary bolt sits above or below the main cylinder and does a narrower job: it lets you open the door a crack to see who's there without letting them push their way in, and it slows down anyone who's already got past the main lock.

It is not, on its own, real security. Chains are thin metal fixed with short screws into a door frame that's often no stronger than the chain itself, and a firm shoulder against the door can pop them. They're a convenience and a second obstacle, not a substitute for a good cylinder.

Where they earn their keep is on doors that get opened to strangers a lot, or in houses where a ground-floor door benefits from a second point of resistance. Fitting one is a small job, usually well under an hour once the main lock work is done.

Smart locks: convenience and an overview, not necessarily more security

A smart lock replaces the key with a code, a phone app, a fob or some combination of these, and often logs who opened the door and when. For a korteriühistu managing a shared entrance, or a household that's tired of cutting spare keys for cleaners and guests, that's genuinely useful.

What it does not automatically do is make the door harder to force open. The mechanical part behind a smart lock still needs to be a decent cylinder or deadbolt; a smart lock bolted onto a weak mechanism is still a weak door, just with an app attached.

Smart locks also add things a plain key doesn't have: batteries to keep charged, a wifi or Bluetooth connection that can drop out, and a bit more that can go wrong mechanically. For most people that's a fair trade for the convenience, but it's worth going in with eyes open.

As one of our smart home installations, from 90 € per job, fitting covers the lock itself, pairing it with your phone or the building's system, and checking it sits properly in the existing door and frame.

What we would fit on a typical Tallinn flat

For most flats, our starting point is the same: get the cylinder right first. A good-quality cylinder with a well-fitted strike plate does more for security than anything bolted on afterwards, and it's the cheapest of the three upgrades to do properly.

A chain or secondary bolt is worth adding if you regularly answer the door to people you don't know, or if the flat is on the ground floor. It's a modest extra cost on top of a lock job and doesn't need its own visit.

A smart lock is worth it for the convenience it brings — no keys to lose, easy to let in a cleaner or a guest without being home — provided the mechanical lock underneath is solid. We'd fit the two together rather than swap a good cylinder for a smart one that isn't as strong.

• Weak or worn cylinder: replace it first, from 60 €
• Ground-floor flat or frequent visitors: add a chain or secondary bolt
• Want keyless entry, shared building access or usage logs: add a smart lock, from 90 €
• Budget for one upgrade only: put it into the cylinder, not the extras

When to call a locksmith rather than try it yourself

Swapping a cylinder sounds simple and often is, but it's easy to buy the wrong size, get the wrong side round, or find that the strike plate and frame need adjusting too, especially on older wooden doors in Kalamaja or Nõmme where nothing is quite standard any more.

Smart locks add a wiring and pairing step that's straightforward when it goes right and fiddly when it doesn't, particularly on a communal door where the whole korteriühistu needs it to keep working.

If you've locked yourself out, if the cylinder has snapped in the door, or if you just want the job done once and done properly, it's worth calling in rather than working through it by trial and error. We're on call around the clock for anyone genuinely stuck outside their own door.