Are smart door locks secure enough for a front door?

Smart locks are genuinely useful for households with cleaners, carers, guests or teenagers who lose keys, because you can issue and withdraw access without cutting metal. The security question is simpler than the marketing suggests: the electronics decide who gets in, the mechanics decide whether the door holds.

Step by step

1. Separate the two halves of the product.There is a mechanical lock — a euro cylinder, a mortice lock or a multipoint strip — and there is an electronic layer that turns it. Ask what the mechanical half is rated to before asking anything about the app.
2. Insist on the same standard you would want anyway.TS007 three-star or Sold Secure Diamond on a euro cylinder, BS3621 on a timber door mortice. A smart lock without a recognised mechanical rating is a convenience product, and your insurer may treat it as one.
3. Check the retrofit type.Some smart locks replace the whole cylinder; some clamp over the inside thumbturn and leave the original lock intact. The clamp-on type is much easier to fit and to reverse, and it keeps whatever rating the existing cylinder has.
4. Plan for a flat battery.Ask what happens when the batteries die: a physical key override, an external contact for a power pack, or nothing. Ask how it warns you, and how long the warning gives you. This is the failure people actually meet.
5. Plan for a lost or dead phone.A keypad, a fob, or a key carried by someone else. A lock whose only credential is one phone is a lockout waiting to happen.
6. Ask what happens if the manufacturer's servers go down.Good products keep local Bluetooth or keypad access working when the internet is off. Products where every unlock is a round trip to a cloud service fail as a group when that service does.
7. Check the account security, because it is now part of your front door.A unique long password, two-factor authentication turned on, and access codes for visitors that expire rather than live forever. Review the access list when a cleaner or lodger leaves.
8. Think about escape as well as entry.Everyone in the house has to be able to get out quickly in the dark, including children and anyone who does not use a smartphone. If the answer involves an app, it is the wrong answer.
9. Tell your insurer.Policies often specify a lock standard by name. Confirm in writing that what you are fitting meets it before you fit it, not after a claim.

Tips

• Keep a conventional key with someone you trust. It is the fix for almost every smart-lock failure mode at once.
• Change the batteries on a date, not on a warning. An annual swap costs a few pounds and removes the scenario entirely.
• Auto-unlock by geofence is the feature most likely to surprise you. Try it for a week before relying on it.

Common mistakes

• Buying on app features and ignoring the mechanical rating — The electronics decide convenience; the metal decides resistance. An unrated mechanism with an excellent app is still an unrated mechanism.
• Making one phone the only way in — A dead phone, a lost phone or a software update then locks the household out, usually at the least convenient moment.

If it doesn't work

Alternatives

• Key safe with a police-approved rating: For carers or a regular visitor, a rated key safe fitted out of obvious sight solves the same problem with no batteries and no account. Cheap versions are not worth fitting — look for a recognised attack-tested rating.
• Keyed-alike cylinders: If the real annoyance is carrying four keys, having front, back and garage cylinders keyed alike costs far less than a smart lock and adds no failure modes.
• Smart keypad on an outbuilding first: Fitting one to a shed or side gate for a year tells you how you feel about batteries and apps before it is between you and your house.

Questions people ask