A security door lock is a high-resistance lock fitted to an entry or security door, usually a deadbolt or multipoint lock. In Sydney, deadbolt installation costs about $290 (range $170–$460), and replacing a single basic lock costs about $255 (range $140–$400).
This guide explains which types suit which doors, what to check before you buy and how to avoid the common mistakes. It sits under our types of door locks guide.
Key points
- A deadbolt on the front and back doors gives the best security gain for the money.
- The door, frame and strike plate matter as much as the lock itself.
- Exit doors must still allow quick escape, so confirm egress rules before fitting a key-operated deadbolt.
- Use a locksmith with a NSW Class 2C security licence and ask for the licence number.
Security door lock types compared
Each type protects in a different way, so match the lock to the door and how you use it.
| Lock type | How it protects | Best for |
|---|---|---|
| Single-cylinder deadbolt | Solid bolt thrown into the frame, keyed from outside, thumb-turn inside | Front and back timber doors |
| Double-cylinder deadbolt | Keyed on both sides, which resists reaching through glass | Doors with glass panels, with egress checked first |
| Multipoint lock | Several bolts engage along the door edge at once | Aluminium and timber doors needing extra grip |
| Security screen door lock | Lock built into the screen door frame | Screen doors over a main entry; see screen door locks |
| Smart or digital deadbolt | Code, card or app entry with a keyed override | Shared access and short-stay rentals |
| Restricted key cylinder | Keys can only be copied with authority | Rentals, strata and businesses where many people hold keys and tracking copies matters |
Cheap knob locks on rentals are the weakest link we see, and a solid deadbolt is the usual first upgrade.
What makes a security door lock strong
The lock is only one part of the system. Check each of these before you spend money.
- Bolt throw: a longer bolt that sinks deep into the frame is harder to force, so ask your locksmith about the throw on the model.
- Cylinder quality: better cylinders from brands such as Lockwood, Abloy and Lane resist wear and tampering far better than budget hardware.
- Strike plate and screws: long screws that reach the stud stop a kick-in, while short screws into soft timber often split.
- Door and frame condition: a rotten or split frame defeats the lock, so repair or reinforce it before upgrading.
- Australian Standard compliance: look for locksets made to AS 4145, and ask your locksmith to confirm the rating of the model.
- Key control: a restricted cylinder stops casual copying; our restricted key systems guide explains it.
Security door lock for front, back and side doors
Different doors face different risks, and each needs its own approach.
- Front door: fit a deadbolt above the handle set, and check the frame because this is the door most intruders test first.
- Back door: hidden from the street, so a deadbolt and reinforced strike plate matter even more than at the front.
- Laundry and side doors: these often carry only a latch, and a deadbolt costs about $290 (range $170–$460) per door in Sydney.
- Garage internal door: treat it as an external door, because garage roller doors are often the easier way in; see garage and roller door locks.
- Sliding doors: the standard latch is weak, so add a secondary lock or bar; our sliding door locks guide covers the options.
- Windows near doors: a good lock fails if a window beside it opens freely, so read window locks as well.
Security door lock cost in Sydney
These typical Sydney prices include GST and were current in October 2026.
| Job | Price range | Typical |
|---|---|---|
| Deadbolt installation | $170–$460 | $290 |
| Replace a single basic lock | $140–$400 | $255 |
| Rekey, per lock | $52–$140 | $75 |
| Smart or digital lock, supplied and fitted | $345–$920 | $600 |
| Security screen door and multipoint locks | Quoted individually (indicative — get itemised quotes) | Varies by door and brand |
- Bundle doors in one visit: fitting several deadbolts together avoids repeated travel charges.
- Book in business hours: after-hours, weekend and public-holiday call-outs carry a surcharge that varies by locksmith.
- Ask what is included: the quote should list the lock model, keys supplied, labour and any frame work.
- Compare rekeying first: if your current lock is sound, see rekey vs change locks before replacing it.
Safety and exit rules for a security door lock
A strong lock must never trap you inside during a fire or emergency.
- Keep escape quick: NCC exit-door rules expect occupants to open exit doors easily, so ask your locksmith what suits your home.
- Prefer a thumb-turn inside: single-cylinder deadbolts let you leave without hunting for a key.
- Keep keys accessible: if you fit a double-cylinder deadbolt, leave the key in a safe, agreed spot at night.
- Check strata and rental rules: landlords, agents and owners corporations may need to approve lock changes on common or leased doors.
- Test before you rely on it: every household member should be able to open the door from inside without the key.
- Use a licensed installer: a Class 2C locksmith knows egress and fire rules and will ask for ID and proof of residence before opening a home.
Common mistakes to avoid
- Buying the lock but ignoring the frame: a strong deadbolt in a weak frame fails with one kick, so reinforce the frame.
- Fitting short screws: screws that stop in the door jamb instead of the stud are the usual reason doors give way.
- Choosing price over grade: very cheap deadbolts can wear within a few years, especially near the coast where salt corrodes parts.
- Skipping the secondary doors: back and side doors are tested first by opportunists, so lock them to the same standard.
- Leaving spare keys outside: a key under the mat undoes everything; use a key safe instead, as our key safes guide explains.
Security door lock FAQs
What is the best security door lock for a front door?
For most Sydney homes, a quality single-cylinder deadbolt above the handle set, with a reinforced strike plate and a sound frame, is the best value. Add a restricted cylinder if you need to control key copies. A locksmith can match the lock to your door.
How much does a security door lock cost to install?
Deadbolt installation in Sydney typically costs about $290, with a range of $170–$460 (October 2026). Replacing a single basic lock costs about $255. Smart locks cost more, at about $600 supplied and fitted. Specialist security screen and multipoint locks are quoted individually.
Can I fit a security door lock myself?
Handy owners can fit some deadbolts, but alignment, frame reinforcement and exit safety are easy to get wrong. Rentals and strata doors also need approval first. A licensed locksmith checks egress, uses the right screws and tests the lock properly before leaving.
Do I need a licensed locksmith to install a deadbolt?
Locksmiths in NSW work under a Class 2 security licence (Class 2C, security equipment specialist). Ask for the licence number before work starts. A legitimate locksmith also checks your ID or proof of residence before opening a home or car.
Next step: upgrade your entry doors with a licensed locksmith
If you are unsure which lock suits each door, we can inspect your frames, check exit requirements and quote the options. TQN Locksmith’s licensed Sydney team provides itemised prices before work starts. Compare costs in our locksmith cost guide, then book a licensed locksmith.
