Yes, change or rekey your locks on day one after moving in. You cannot know how many keys exist for your new front door, and An Garda Síochána’s home security guidance points to restoring known access control as the sensible first step. The single action that matters most today: book a cylinder swap or rekey with a PSA licensed locksmith before you unpack.

TL;DR:

• A euro cylinder swap usually suffices for uPVC or composite doors, while damaged cylinders, worn gearboxes, or uncertified timber door mortice locks may require replacement.
• For a do it yourself swap, measure the existing cylinder from the fixing screw to each end; guessing can leave it protruding and vulnerable to snapping.
• Ask a locksmith to confirm in writing that locks meet BS3621 or EN1303 where relevant, and keep receipts, photographs, and certification for your insurer.
• Reset smart lock accounts, alarm codes, keypads, and access fobs on moving day; changing the physical cylinder does not remove former occupants’ digital access.
• Secure the main entrance first, then side doors and garage access; ground floor and reachable first floor windows outrank upper floor windows.

Table of Contents

• Day-one checklist: what to do about locks immediately after moving in
• Rekeying versus replacing: which to choose for common door types
• Standards, insurance and safety: what to check so your lock work meets expectations
• DIY vs professional locksmith: when to attempt yourself and when to book a locksmith
• How a local locksmith service like ECS Locksmiths can help when you move in
• Security assessment of the new property before moving in
• How to prioritise which locks to change or rekey first based on risk areas
• Benefits of master key systems for new homeowners
• Importance of updating security codes and access for electronic systems when moving in
• Checklist for keeping records of new locks and keys for future reference
• Author perspective: a locksmith’s quick checklist and common pitfalls
• How ECS Locksmiths can help
• FAQ
• Sources
• Authoritative sources and practical links to official guidance

Day-one checklist: what to do about locks immediately after moving in

Before you do anything else with the boxes, work through the locks. Previous owners, estate agents, tradespeople and former tenants may all hold copies of your keys, so this is not a step to leave for later.

1. Walk the property and list every external door and window lock, noting the type (euro cylinder, mortice, multi-point) and how many keys you were handed.
2. Collect all keys in one place and check them against the number of doors so you know what is missing.
3. Decide whether a cylinder rekey is enough for your uPVC or composite doors, or whether a full mortice lock replacement is needed on timber doors.
4. Fit a temporary chain or door limiter, switch on any existing alarm and leave a hallway light on timer while you arrange permanent work.
5. Book a same day or next day appointment with a locksmith if you would rather not do the work yourself.

Pro Tip: Photograph every lock and key before you touch anything, it gives you a clear record if a dispute over keys ever comes up with an agent or previous owner.

Rekeying versus replacing: which to choose for common door types

Rekeying means changing the pins inside an existing cylinder (or swapping the cylinder entirely) so old keys stop working, without replacing the whole lock body. It is quick, usually cheaper than a full replacement, and restores control over who can get in within the hour on most uPVC and composite doors.

Full replacement makes more sense when the lock itself is old, damaged, or does not meet current standards. A tired mortice lock on a timber door, a cylinder that already sticks or grinds, or a multi-point mechanism with a worn gearbox are all signs that swapping pins will not solve the underlying problem.

• Euro cylinders on uPVC or composite doors: a straightforward cylinder change is often all that is needed to regain control, according to An Garda Síochána’s HS2 guidance.
• Mortice deadlocks on timber doors: these may need replacing outright if they are not certified to the BS3621 standard that insurers commonly expect.
• Multi-point locking systems: the cylinder can usually be changed independently of the gearbox, but a locksmith should check the whole mechanism still aligns correctly afterwards.
• Smart locks: check the new cylinder or retrofit unit is compatible with your door’s backset and spindle before buying, and re-pair the app or hub to your own account rather than trusting a previous owner’s credentials.

Door construction plays a part too, as selecting robust materials like those discussed in timber cladding gates can enhance overall security. Guidance from An Garda Síochána notes that secure doors are typically at least 44 millimetres of hardwood with secure hinges, and that laminated glazing adds resistance where glass panels are fitted. If your new front door falls well short of that, a lock upgrade alone will not close the gap, and it is worth discussing the door itself with whoever carries out the work.

Standards, insurance and safety: what to check so your lock work meets expectations

Two standards come up repeatedly when insurers assess a home’s locks. BS3621 covers thief resistant mortice deadlocks, setting requirements for how hard a lock is to pick, drill or force. EN1303 covers cylinder performance, including resistance to drilling and manipulation. Neither standard guarantees a break-in cannot happen, but both give insurers a benchmark they recognise.

• Ask any locksmith to confirm in writing that replacement locks meet BS3621 or EN1303 where relevant to your door type.
• Keep receipts, photographs of the fitted locks, and any certification paperwork together in one folder for your records.
• Mention lock upgrades to your insurer if your policy asks about security measures, since some policies set conditions around lock standards.

A seasonal reminder worth acting on: the government-backed Lock-Up, Light-Up campaign encourages locking doors, using timer switches for lights, keeping keys away from windows and letterboxes, and using an alarm where one is fitted, treating locks as one layer among several rather than the whole solution.

DIY vs professional locksmith: when to attempt yourself and when to book a locksmith

A straightforward euro cylinder swap on a uPVC or composite door is within reach for a confident DIYer with a screwdriver, a tape measure to get the cylinder length right, and a steady hand. Measuring wrong is the most common mistake, so take the old cylinder out and measure it rather than guessing from the door thickness.

1. Measure the existing cylinder from the centre of the fixing screw to each end before ordering a replacement.
2. Remove the single fixing screw on the edge of the door, slide the old cylinder out, and fit the new one the same way round.
3. Test the door locks and unlocks smoothly from both sides before considering the job finished.

Call a locksmith instead when the work involves a mortice lock, when the door or frame shows signs of damage or warping, when you are dealing with a multi-point mechanism that will not align, or when you want a smart lock integrated properly with existing hardware. A rushed DIY job on a mortice lock or multi-point system can leave a door that looks locked but is not secure.

Simple DIY cylinder kits typically cost a small amount for parts and take under half an hour. A professional visit costs more but includes diagnosis, correct fitting and, where needed, paperwork for insurers. Always use a locksmith licensed by the Private Security Authority for on-site work, as An Garda Síochána recommends, rather than an unverified tradesperson.

Pro Tip: If you are even slightly unsure which cylinder size or lock type you need, send a photo of the existing lock to a locksmith before buying anything, it saves a second trip to the shop.

How a local locksmith service like ECS Locksmiths can help when you move in

A professional visit solves the problems that trip up DIY attempts: matching cylinder sizes, fitting a BS3621 compliant mortice deadlock correctly, and making sure a multi-point mechanism still closes properly once the cylinder changes. It also leaves you with paperwork an insurer may ask for.

• Rekeying and cylinder swaps on uPVC, composite and timber doors.
• Mortice deadlock installation to current standards.
• Smart lock fitting and setup, including re-pairing to a new account.
• Emergency callouts for lockouts on moving day itself.
• Documentation of work carried out, useful for insurance records.

Security assessment of the new property before moving in

A short walk-through before the moving van arrives tells you far more than relying on what the seller or agent mentioned in passing. Check every external door for how the lock engages, whether the frame feels solid when you push against it, and whether hinges are screwed in firmly rather than just resting in place.

Windows deserve the same attention, particularly ground-floor and easily reached first-floor windows. Look for working window locks, not just a handle that turns, and check that keys exist for any lockable window handles. A garage connected to the house is effectively another entry point and is often overlooked.

Note anything that looks like a past break-in repair, a replaced panel, a patched frame, or a lock that looks newer than the rest of the door. These are not red flags on their own, but they are worth asking the previous owner or agent about before you finalise your moving-in plans.

Walk the perimeter at dusk too. Poor lighting around side gates and back doors is exactly what the Lock-Up, Light-Up campaign targets, and a cheap timer light often closes that gap faster than any lock change.

How to prioritise which locks to change or rekey first based on risk areas

Not every lock needs attention on day one, and trying to do all of them at once usually means doing none of them well. Work outwards from the doors a stranger could use without being noticed.

Start with the main entrance, front and back doors are the highest priority because they see the most key copies over a property’s lifetime, from previous owners to cleaners to tradespeople. Side doors and any door opening directly from a garage into the house come next, since garages are often left unlocked during a move and are easy to overlook.

Ground-floor and easily accessible windows rank above upper-floor windows, especially any with a lockable handle where you were not given a key. Garden gates and sheds matter less for personal safety but still deserve a glance, since tools left behind can make a break-in easier elsewhere on the property.

Treat this as a sequence rather than a single job: secure the main entrance today, work through side access points within the first week, and leave lower-risk areas like shed locks for whenever you get to them.

Benefits of master key systems for new homeowners

A master key system lets one key open several locks around the property, while individual keys still work only on their own doors. For a new home with a side door, a garden gate and perhaps an outbuilding, this means carrying one key instead of three without weakening security on any individual lock.

The practical benefit shows up most during a move itself, when tradespeople, family helping you unpack or a cleaner might need access to specific areas without a key to everything. A well-designed master key system lets you grant that access to one door while keeping the rest on separate keys.

It also simplifies future rekeying. If you later want to change access for just the garden gate without touching the front door, a properly set up master system makes that a single, contained job rather than a full rethink of every lock on the property.

Master key systems suit homes with several outbuildings or a mix of shared and private areas more than a simple terraced house with one front and back door, where the extra complexity may not be worth it.

Importance of updating security codes and access for electronic systems when moving in

Physical keys are not the only thing to change hands with a property. If the home has an electronic keypad, a smart lock, an alarm system or any access control panel, the previous occupant’s codes and app access need resetting before you treat the property as secure.

A smart lock left on a previous owner’s account can potentially still be unlocked remotely by someone who kept their login details, even after you change the physical cylinder. Resetting the lock to factory settings and re-pairing it to your own account closes that gap.

Alarm systems often ship with a default code that gets changed on installation, so check whether the existing code is still the installer’s default or something the previous owner chose, and reset it either way. The same applies to any garage door keypad, gate entry system or shared building access fob.

Treat this as part of the same day-one process as changing physical locks, not a separate task for later. An unresolved digital access point defeats the purpose of a fresh cylinder on the front door.

Checklist for keeping records of new locks and keys for future reference

Once the locks are sorted, the paperwork is worth five minutes of your time. A simple record saves confusion later, whether you are dealing with an insurance claim, lending a key to a neighbour, or selling the property years from now.

• Note the make, model and standard (BS3621 or EN1303 where relevant) of every lock fitted.
• Keep receipts and any locksmith paperwork together in one folder, physical or digital.
• Photograph each lock once fitted, along with the key or fob issued for it.
• Record how many keys exist for each lock and who holds a copy.
• Store spare keys somewhere secure but memorable, not inside the house they open.

Author perspective: a locksmith’s quick checklist and common pitfalls

The mistake I see most often is ordering a cylinder by eye rather than measuring the old one out of the door. Get that wrong and you are back at the shop for a second trip, or worse, fitting a cylinder that sits slightly proud of the door edge and can be gripped and snapped from outside.

Frame strength gets overlooked too. A brand new, standards-compliant lock fitted into a soft or rotten frame is not much of an upgrade. Check the frame before you spend money on the lock.

My quick list: measure twice, keep every receipt, do not assume a smart lock’s factory reset button is where the manual says it is, and when a job involves a mortice lock or a multi-point system, call a PSA licensed professional rather than guessing.

— Barry

How ECS Locksmiths can help

If the checklist above has you reaching for the phone rather than a screwdriver, that is exactly the point where we come in. We handle same-day rekeying, cylinder swaps, mortice deadlock installation and smart lock fitting, so your new home is secured properly before your first night there.

We also cover emergency callouts if you find yourself locked out on moving day itself, and we leave you with the paperwork an insurer might ask for. Visit our services page to see the full range or book a callout, or find your nearest team through our locksmith Dublin page.

FAQ

Should I change the locks when I move into a new house?

Yes, changing or rekeying locks on moving day is the sensible default, since you cannot know how many keys exist for the property. A simple cylinder swap on a uPVC or composite door usually restores control within an hour.

Do you need to change the locks on a new house?

There is no legal requirement to change locks on a new house, but it is widely recommended practice because previous owners, agents and tradespeople may hold copies of existing keys. A rekey or cylinder change closes that gap quickly and affordably.

What is the first thing you do when you move into a new house?

Before unpacking, walk the property and list every external lock, gather all keys you were given, and decide which locks need rekeying or replacing first, starting with the main entrance. Fitting a temporary chain or limiter and switching on any existing alarm covers you while you arrange permanent work.

Can you change house locks by yourself?

A straightforward euro cylinder swap on a uPVC or composite door is manageable for a confident DIYer with the correct cylinder measurements. Mortice locks, damaged frames and multi-point systems are better left to a PSA licensed locksmith to avoid leaving the door looking secure without actually being secure.

Sources

• HS2 Home Security Doors (An Garda Síochána)
• Gov

Authoritative sources and practical links to official guidance

The guidance behind this article comes from official crime-prevention sources rather than general advice. An Garda Síochána’s home security guidance covers door standards, cylinder advice and PSA licensing, while the government’s seasonal campaign covers lighting and layered security. For booking work on your own property, our services page lists rekeying, installation and emergency callout options.

Recommended

• Expert Locksmiths in Dublin
• Expert Locksmiths in Glasnevin
• Expert Locksmiths in Rathfarnham