Changing Locks in a New House: Why It's Job One

When you pick up the keys to a new home, changing the locks should be near the top of your list — ideally on day one, before the first night you sleep there. It feels like an odd priority when there are boxes everywhere and the broadband isn't sorted, but it's the single quickest thing you can do to make the place genuinely yours. Changing the locks in a new house isn't paranoia; it's the only way to know who can actually open your front door.

Here's why it matters, what to change, and what it realistically costs in Manchester.

You have no idea how many keys exist

This is the heart of it. When you bought or rented your home, you were handed a set of keys. What you weren't handed is a guarantee that those are the only keys.

Over the years, copies tend to multiply, and previous occupants rarely keep track. The list of people who may hold a working key to your new home can include:

• The previous owners and their grown-up children.
• Former tenants who never returned every set.
• Cleaners, dog-walkers and babysitters.
• Tradespeople — builders, decorators, gardeners — who were given a key "just for the week".
• Neighbours who held a spare.
• The estate or letting agent, who may have kept a copy.

None of these people is necessarily a threat. The point is that you cannot know, and you cannot retrieve keys you don't know exist. Changing the locks resets the count to zero: from that moment, the only keys that work are the ones in your hand.

What to change — every external door

The rule is simple: secure every door that leads from outside into the house. That means the front, the back, any side door, and the door from an attached garage or conservatory if it opens into the living space.

It's tempting to do only the front door because it's the obvious one. Don't. Burglars strongly prefer back and side doors precisely because they're hidden from the street, and a back door still on the previous owner's key undoes everything you achieved at the front. If you're paying a locksmith to come out, the marginal cost of doing the back door at the same visit is small.

Internal doors you can almost always ignore. Bathroom and bedroom locks are about privacy, not security, and old keys to them pose no real risk.

Rekey or replace?

You have two ways to make the old keys useless, and the right one depends on the locks already fitted.

Rekeying keeps the existing lock and changes its internal pins so old keys no longer turn. It's the cheaper option at roughly £45–£65 per lock, and it's ideal when the existing locks are modern, sound and already to a decent standard.

Replacing swaps the whole lock for a new one — roughly £70–£150 per lock, or more for a British Standard mortice. It's the better choice when the existing locks are old, worn, sticking, or below the standard your insurer expects. We go into the rekey-versus-replace decision in more depth in our guide on what to do when you've lost your keys, and the logic is the same here.

On a uPVC door, "changing the lock" usually means swapping the Euro cylinder — the barrel the key turns. That's quick and inexpensive, and it's the natural moment to fit a better cylinder than the developer originally chose.

Upgrade while you're at it

Moving in is the ideal time to bring your doors up to standard, because the locksmith is already there and the doors are getting attention anyway. Two upgrades pay for themselves:

On uPVC and composite doors, fit a 3-star anti-snap cylinder. Standard developer cylinders are defeated by lock snapping in seconds; an anti-snap cylinder closes that off. A standard cylinder fitted is £80–£180, an anti-snap one £140–£250 — the extra is modest for the protection it buys.

On wooden doors, make sure the mortice lock is a BS3621 five-lever, the thief-resistant standard most insurers require on final-exit doors. You can tell a BS3621 lock by the Kitemark stamped on the faceplate. A BS3621 mortice fitted runs £140–£280. Our explainer on what BS3621 actually means is worth a read if your insurance renewal has ever mentioned "British Standard locks".

Manchester's housing varies enough that the right upgrade depends on where you've landed. The Victorian terraces around Didsbury and Chorlton tend to have wooden doors and mortice locks, so BS3621 is the thing to check. Newer builds and estate housing in Salford lean towards uPVC and composite doors, where the anti-snap cylinder is the priority.

What it costs for a typical house

Putting it together, a typical two-door Manchester home comes to somewhere between £150 and £450, depending on whether you rekey or replace and whether you take the upgrades. A flat with a single entrance door is cheaper; a larger house with three or four external doors costs more.

Our lock replacement page sets out the full pricing, and we'll always give you a firm quote on the phone once you've told us the door types and how many you need doing. There are no call-out surprises and no pressure to replace locks that only need rekeying.

A note for landlords

If you let property, changing or rekeying the locks between every tenancy is one of the cheapest forms of risk management you have. A departing tenant may have kept a set, copied one, or passed one to a friend or partner — and the next tenant has every right to expect that nobody else can walk in.

There's no single law forcing it, but a landlord who hands over a home a previous tenant can still access is on shaky ground if anything goes wrong. Rekeying is quick and cheap, and many letting agents already do it as standard turnover work. It's a small cost set against the goodwill of a tenant who feels genuinely secure from day one.

Don't forget the spares and the rest of the keyring

Changing the locks resets your security, but only if you account for every set of keys that comes with them. When you take ownership, you're often handed a fistful of keys on various rings — some for doors, some for windows, some you can't identify at all. Sort them before you decide what to change.

Pay particular attention to window locks, which many people forget entirely. If the previous owners had key-operated window locks and the keys are missing or shared, those windows are a weak point regardless of how good your door locks are — and most insurers expect key-operated locks on accessible windows to be in working order. It's worth checking they all lock and that you have the keys.

Garages, sheds and outbuildings are the other commonly overlooked spot. A garage that connects to the house is effectively an external door and should be treated as one. A detached shed full of tools matters too, because a burglar's first stop is often the garden store for something to lever your back door with.

A simple first-week checklist

To keep it manageable amid the chaos of moving, here's the order that makes sense:

• Day one: change or rekey the main door you'll use, so your first night is on keys only you hold.
• First few days: do the remaining external doors — back, side, garage-to-house.
• First week: check every window lock works and you have the keys; sort any that don't.
• While you're at it: upgrade to anti-snap cylinders or BS3621 mortices where the existing locks fall short.
• Keep a spare safe: once it's all done, label and store a spare set somewhere sensible — not under the doormat.

It looks like a lot written down, but most of it happens in one locksmith visit. The point is simply to be deliberate rather than leaving it to chance.

When to call a locksmith

Call before you move in if you can, so the locks are sorted before your first night. If completion day is hectic, calling within the first few days is fine — just don't let it slide into "next month", because that's when it gets forgotten. If you've moved in and discovered a door won't lock properly at all, that's a repair as much as a security job; our uPVC door repair service covers the common alignment and mechanism faults on plastic doors.

Tell us your postcode, how many external doors you have and what they're made of, and we'll talk you through whether rekeying or replacing makes sense — and give you a straight price before we set off.