Lost keys: should you change the lock cylinder or not?

Do you need to change the cylinder after losing a key?

Not always, but you should whenever a finder could link the key to your door. Whether to change the lock cylinder or not therefore depends on the risk, not on the key alone.

The lock cylinder is the part you put your key into, and it alone decides which key opens the door. As long as the lost key exists somewhere, it still works, even if you already have a spare in your pocket. Only a new cylinder makes the old key useless.

A key with nothing to identify a name or address is usually worthless to whoever finds it. But as soon as it can be traced to your home, the loss becomes a security problem you should not put off.

How do you assess the risk after losing your keys?

Ask yourself one simple question: could someone find my door with this key? The more of the following points apply, the sooner you should act.

• Your key ring has a tag with your name, address or phone number.
• The key was together with your ID, wallet or letters showing your address.
• You lost it near your home, in the stairwell or outside the building.
• The key was stolen, for example with your bag or rucksack.
• It is a key to a master key system that opens several doors in the building.
• You are not sure where or when the key went missing.

If none of these points apply, for instance because the key disappeared on a hike or during a swim in the lake, the risk is usually low. Many people then decide against an immediate replacement. If you still feel uneasy, a new cylinder remains the safe choice.

Stolen or lost - why does it make a difference?

A stolen key is far more serious than a lost one, because someone took it on purpose. The thief often has your address as well, from your ID or other papers.

So after a theft, do not wait. Report it to the cantonal police and have the cylinder replaced as soon as possible. Your insurer will usually ask for the police confirmation too.

A lost key, on the other hand, is often just lying somewhere with nobody knowing what it belongs to. In that case, check with the lost property office and the places you last visited before you decide.

A key taken from your letterbox, car or bike basket also counts as stolen. In such cases, the thief often knows where you live or where you regularly spend time. Note down the time and place of the theft while your memory is fresh; it makes the police report and any later questions from your insurer much easier.

Renting a flat: why must you tell the property management?

If you rent, report the loss promptly to the property management or your landlord. The decision about the cylinder is not yours alone, because the locks are part of the rented property.

Many apartment buildings in Switzerland have a master key system: your flat key often also opens the main entrance, cellar, laundry room or letterbox. If such a key goes missing, it can affect everyone in the building. The property management will decide whether only your cylinder or part of the system needs to be changed. Our guide Lost a key to a master key system explains this in more detail.

Do not fit a cylinder from outside the system on your own initiative, as this can cause problems when you move out. Who covers the cost depends on the circumstances, your tenancy agreement and your insurance; see Who pays for the locksmith? for an overview.

Own house: new cylinder or new key system?

In your own home, you decide how far to go. In most cases it is enough to replace the cylinders of the doors the lost key opened.

A cylinder replacement is a quick job: the forend screw, the fixing screw on the edge of the door, is undone, the old cylinder is pulled out and a new one inserted. The lock inside the door stays where it is. If the key opened several keyed-alike doors, such as the front door, garage and cellar, all of those cylinders need replacing.

If you own a small key system of your own, for example for a house with a granny flat or office, things are more complex. Depending on the system, individual cylinders have to be recoded or replaced. With electronic systems, a lost key can often simply be blocked without changing any cylinder.

Lost keys: the steps in the right order

Work through it methodically. That way nothing gets forgotten and you have all the paperwork ready for your landlord and insurer.

1. Retrace your steps and ask wherever you were last, such as a restaurant, shop or your workplace.
2. Report the loss to your municipality's lost property office, or to the transport company's lost property service if you lost it on a train, bus or tram.
3. If the key was stolen, report it to the cantonal police and ask for written confirmation.
4. If you rent, tell the property management or your landlord straight away.
5. Notify your insurer and clarify which costs they will cover.
6. Decide, based on the risk, whether to change the cylinder or not, and keep all invoices.

If you notice signs that someone is tampering with your door, call the police on 117 immediately.

Getting a spare key cut: what applies to security cylinders?

A spare gives you a second key again, but it does nothing about the risk from the lost one. It makes sense when the key cannot be linked to any door.

For standard cylinders, our key service can copy a key from an existing one. Security cylinders are different: they come with a security card. Duplicates are only cut by an authorised dealer or the manufacturer, and only when this card is presented. This copy protection stops strangers from having keys made without your knowledge.

Keep the card separate from your keys, never in your wallet. In rented flats it is usually held by the property management, who order spare keys for you. If the card itself is lost, a new cylinder with a new card is often the simpler solution.

After a cylinder replacement, order enough keys straight away, for example one for every member of the household. A spare left with someone you trust nearby will often save you a long wait outside your door the next time something goes wrong.

How BLITZAUF24 helps after you lose a key

We are available around the clock, including if you are locked out after losing your keys. Before opening a door or replacing a cylinder, we check that you are entitled to access, for example with ID and your tenancy agreement or other proof of residence.

We tell you the price before any work starts. If the right system cylinder has to be ordered first, we can fit a temporary cylinder so your door locks securely again straight away. You can pay in cash, by card, with TWINT or by invoice.