Thinking about swapping your door keys for a smart lock?

Many models are designed for DIY fitting on a standard door, but the right choice depends on your door, your existing lock and your insurance.

Here's a step-by-step guide on how to fit one - and when bringing in a checked locksmith makes more sense.

The easier way to book quality trades

Download app

How does a smart lock work?

A smart lock replaces or adds to your existing lock so it can be operated without a traditional key. You control it with a smartphone app, a keypad, a fingerprint reader, a key fob or a voice assistant, depending on the model.

Most smart locks connect to your phone using Bluetooth or wifi. A wifi connection (or a separate hub or bridge, on some models) lets you lock and unlock the door remotely, which is handy if you ever wonder whether you left it unlocked.

Many models also offer:

• Temporary or one-off access codes, for a cleaner or dog walker

• Automatic locking after a set time

• Activity logs showing when the door was locked or unlocked

• Links to smart home systems such as Amazon Alexa or Google Home

Is your door suitable for a smart lock?

Smart locks come in a few types, and not every type fits every door. The main approaches to installing one are:

• Cylinder replacement: Swaps your existing euro cylinder for a smart one. Common on uPVC and composite doors

• Retrofit (over the existing lock): Fits over the inside of your current lock and operates the existing mechanism, so the outside stays as it is

• Full replacement lock: Replaces the whole lock body, typically on timber doors

First things first, you'll need to measure your door thickness and check your cylinder size and lock type against the manufacturer's compatibility guide.

Manufacturers usually supply different fixing packs for different door thicknesses, so the measurement matters.

Not sure which lock suits your door? Our guide to keyless door locks explains the options, and our locksmith hub brings everything together in one place.

How to install a smart lock

If you are confident with basic DIY, you can follow these steps. Always put the manufacturer's instructions first, as every model is fitted slightly differently.

What you need:

• Your smart lock and everything in the box (fixing packs, batteries, keys)

• A screwdriver set, tape measure and pencil

• A drill, if the instructions call for it

• Your phone, with the lock's app downloaded

• A dust sheet to protect the floor

Step-by-step smart lock installation

1. Read the instructions first

Check you have the correct fixing pack for your door thickness before you remove anything.

2. Keep the door open

Leave the door open throughout, and keep the old key to hand, so you cannot lock yourself out.

3. Remove the existing lock or cylinder

Unscrew the fixings and take out the old lock or cylinder following the instructions (our guide to changing a uPVC door lock shows how to remove a euro cylinder). Do not drill out a lock unless the manufacturer says to.

4. Check the fit

Compare the new lock against your measurements, such as the cylinder length and the distance from the lock to the edge of the door.

5. Fit the new lock

Attach the lock, mounting plate or cylinder as shown in the guide, and fit the batteries.

However, if your smart lock needs hardwiring into your home's electrical supply, it's best to call a qualified electrician rather than attempt the wiring yourself.

Need reassurance? All tradespeople pass up to 12 checks before joining, and we keep checking after.

No hardwiring needed? Then continue with the steps below.

6. Pair it with the app

Follow the app's set-up steps to connect the lock to your phone, and to your wifi or hub if the model uses one.

7. Test it with the door open

Lock and unlock several times using the app, keypad and key. Check the bolt moves freely and lines up with the strike plate.

8. Test it with the door closed

Only once everything works, close the door and test again, with someone inside or your key in your pocket.

Finally, make sure to follow the manufacturer's instructions closely, as each lock is slightly different and give yourself enough time for the job (more on that below).

If you are at all unsure, we strongly recommend hiring a professional locksmith so you can have peace of mind that your home is secure.

Need peace of mind? Every Checkatrade job is backed by the £1,000 guarantee.

Up to £1,000. Eligibility criteria and T&C’s apply.

How long does it take to install a smart lock?

It's important to give yourself a decent window of time to fit your smart lock properly. Rushing the job could compromise your home's security.

As a rough guide, allow around two hours to remove an existing lock and fit a compatible smart lock.

However, the job may take longer if you're working with an unfamiliar locking mechanism. Which brings us to...

Risks of installing a smart lock yourself

DIY smart lock installation does carry some risks:

• Damage to the door or lock: Drilling or forcing parts into the wrong place can mark or weaken a door

• A weaker lock if fitted badly: A lock that is misaligned or not fully secured may not protect your home as it should

• Wiring mistakes: On models that need a wired power supply, incorrect connections can cause faults. Leave mains wiring to a qualified electrician

• Insurance and warranty issues: Check your insurer's requirements for external door locks, and the manufacturer's terms, as some products are only warranted when installed in a particular way

If you are not comfortable with any step, stop and ask a locksmith to do it.

Smart lock advantages and disadvantages

Smart locks are not right for everyone. Here is how the pros and cons stack up:

Advantages of a smart lock:

• Remote access: Let people in when you are not at home

• Convenience: Give out temporary codes and stop worrying about spare keys

• Visibility: Keep an eye on who comes and goes with activity logs

• Smart home links: Connect the lock to other devices, where the model supports it

Planning your smart home

Ready to embrace the benefits of a smart home? Read our guide to help you plan your smart home from start to finish.

Learn more

Disadvantages of a smart lock:

• Reliance on technology: A flat battery, a lost phone or a connection problem can make it harder to get in, so keep a backup key or access method

• Higher cost: They usually cost more than a standard lock

• Cyber security: As with any connected device, your account and lock need protecting

• Maintenance: Batteries need replacing and software needs updating

Overall, a smart lock can add convenience and, if it meets the right security standard, strong protection. But always weigh up the pros and cons before you buy.

How to keep your smart lock secure

A few habits make a big difference, in line with National Cyber Security Centre advice for smart devices:

• Install software and firmware updates, and switch on automatic updates if the option is available

• Turn on two-step verification for the lock's app and account if it is offered

• Change any default password, and use a strong, unique one (for example, three random words)

• Avoid easy-to-guess keypad codes, and remove codes for people who no longer need access

What is lock snapping and how can I prevent it?

Lock snapping is a common way for burglars to break into properties. And worse, it requires zero skill. Here, we’ll explain exactly what lock snapping is and how you can prevent it.

Learn more

Smart lock installation: when to hire a professional

Hiring a locksmith is worth considering if:

• Your door is uPVC, composite or glazed and you are not sure which lock fits

• The lock needs hardwiring or other electrical work

• You need the lock to meet an insurance requirement

• You are replacing several locks

• You simply want the job done and the lock tested properly

A professional can recommend a lock suited to your door, fit it correctly and help make sure it works with your insurance.

How much does professional smart lock installation cost?

Smart lock prices start at £63 for a basic keypad lock and reach around £210 for Z-Wave.

That said, the final price depends on the keyless door lock you choose, your door and the type of installation.

Our smart locks cost guide explains what to expect, and our locksmith prices guide covers wider locksmith work.

How much do smart locks cost in 2026?

If you're looking for a way to keep your home safe using the latest technology, a smart lock system could be the answer. Smart lock installation will transform your home security by swapping traditional keys for keyless entry. In this smart locks cost guide, we'll look at the average cost of keyless entry systems for your home.

Learn more

Or use our cost calculator below for a quick estimate.

Job Estimate Calculator

Get Started

Step 0/3

Preparing for your smart lock installation

Smart lock installation checklist

• Check door compatibility

• Confirm insurance requirements

• Measure door thickness

• Download the app

• Keep the old key

• Test with the door open

• Set a strong code

• Switch on updates

• Leave any hardwiring to a qualified electrician

• If in doubt, hire a locksmith for the job instead

Smart locks often sit alongside other home security upgrades. A locksmith can fit the lock, while our home security hub covers alarms and CCTV.

FAQs

Checkatrade

Follow us

More Digital Smart Door Lock Installation Articles

How much do smart locks cost in 2026?

Locksmith prices in the UK in 2026

Types of locks for front doors

View all