When you move into a new home, previous owners, estate agents, builders and cleaners may all hold working keys. Changing cylinders on moving day is the single most practical security step for any new property.
Who Has a Key to Your New Home?
When you move into a property — bought or rented — you inherit its entire key history. Previous owners may have given copies to family, friends, cleaners, babysitters and former partners. Estate agents routinely hold keys throughout the sale process. Builders, plumbers and electricians who worked on the property may have cut copies before returning the original. Managing agents and letting companies often hold copies as standard practice.
None of these people have any particular reason to return or destroy their copies when you move in.
What Changing the Locks Involves
Changing the locks means replacing the cylinder — the oval barrel inside the lock that the key operates. The lock body itself stays in place. The old cylinder comes out, a new one goes in, and all previous keys stop working immediately.
For most South London homes this takes 20–30 minutes per door and costs £55–£85 per cylinder including the new part.
Upgrade at the Same Time
A move is the ideal time to upgrade to an anti-snap TS007 3-star cylinder. You will have a locksmith visiting anyway. Adding Ultion, ERA Fortis or Yale Platinum 3-star costs slightly more than a basic cylinder replacement and provides significantly better protection against cylinder snapping — the most common burglary technique in South London.
How Many Cylinders?
Most houses need: front door (1 cylinder) and back door (1 cylinder). Some properties have a side gate or garage entry with a cylinder lock. Most flats require just the front door.
Re-Keying vs Replacing
Re-keying alters the existing cylinder pins so old keys stop working. Replacing fits an entirely new cylinder. For a new home, replacement is almost always preferable — it is the opportunity to fit a better cylinder, and costs no more than re-keying a good quality one.
When to Do It
Ideally on moving day or the day before — before you unpack valuables and before anyone with a previous key could observe your new routine.
TrustLock provides same-day cylinder changes across Dulwich, East Dulwich, Peckham, Camberwell, Herne Hill, Brixton and Southwark. Call 07984 547185.