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The short answer
Measure your door and identify your lock type before looking at any product, because fit is what rules most models out. Then decide how you want to open it: a keypad is the most reliable, fingerprint is the fastest, and phone-based unlocking is the least dependable. Always keep a physical key and know where it is.
Smart locks are one of the few smart home products that must work every single time. A light that fails is an annoyance; a lock that fails leaves you outside. That reframes the buying decision around reliability, power and backup rather than around features.
Fit comes first
Lock mechanisms differ substantially between regions and door types, and a lock designed for one will not fit another. Before shopping:
Identify your lock type
A deadbolt with a separate handle, a knob lock, a mortice, a multipoint mechanism or a euro cylinder. Each has different smart options.
Measure the door thickness
Most locks state a supported range, and doors outside it need spacers or a different model.
Measure the backset
The distance from the door edge to the centre of the lock hole, typically 60 or 70mm.
Photograph both sides of the existing lock
Useful for compatibility checkers and for asking before buying.
Check the door closes and locks easily now
A door that binds will drain a smart lock’s batteries quickly and eventually fail to throw the bolt. Fix the door first.
A door that needs a shoulder to close is not a candidate for a smart lock until it is adjusted. Motors are much weaker than a human hand, and a binding bolt is the single most common cause of smart locks failing to lock and of batteries lasting weeks instead of months.
How you will open it
- Keypad: the most reliable, works for guests and cleaners, needs no phone. Codes can be temporary.
- Fingerprint: fastest in practice, and less reliable with wet or cold hands. Best as one option among several rather than the only one.
- Phone via Bluetooth: convenient, dependent on the app running and the phone having battery.
- Auto-unlock on approach: pleasant when it works, and it depends on background location, which phones suppress to save battery. Expect inconsistency.
- Physical key: the one that always works. Keep it, and keep it somewhere you can reach without entering the house.
The practical answer for most households is a keypad as the primary method, with a phone as a convenience and a key as backup.
Locks worth considering
TEEHO TE001 keyless entry deadbolt with keypad
A sensible first smart lock: it replaces the deadbolt, opens with a code, and does not depend on your phone or an internet connection to work. That simplicity is a feature, since fewer dependencies means fewer ways to be locked out.
Schlage Encode smart Wi-Fi deadbolt lock
Built-in Wi-Fi removes the bridge, which is the component people place badly and then wonder why remote access is unreliable. Schlage’s mechanical quality is the other reason to consider it: the lock itself is a proper lock rather than a smart device with a bolt attached.
Wyze Auto-Lock Bolt v2 with fingerprint keyless entry
Fingerprint is the fastest way to open a door when it works, and pairing it with automatic locking removes the question of whether you locked up. Expect fingerprint reading to be less reliable with wet hands, and make sure a code or key backup is configured.
Fingerprint smart door knob with keypad, keyless entry
Not every door has a deadbolt, and a knob replacement is the option for those that do not. Bear in mind that a knob lock is less secure than a deadbolt regardless of how smart it is, so this is about convenience rather than upgraded security.
Yamiry keypad smart door knob lock with handle
A combined unit avoids aligning a separate handle and deadbolt, which makes fitting simpler on doors where the two currently disagree. As with any knob or handle lock, treat it as convenience rather than a security upgrade, and keep a deadbolt if the door has one.
What we liked
- No keys to lose or copy
- Temporary codes for guests and tradespeople
- Auto-locking removes the did-I-lock-it question
- Activity logs show who came and went
What we didn't
- Batteries need attention and fail at bad moments
- Phone-based unlocking is the least reliable method
- A binding door defeats the motor
- Not every lock fits every door
Power and backup
Smart locks run on batteries, usually AA cells, for six to twelve months. Lithium cells last considerably longer in cold weather, which matters for an exterior door in winter.
Every sensible lock has a backup: a physical key, external contacts for a power bank, or both. Before buying, know which yours has and make sure the corresponding backup exists. A key in a safe place that is not inside the house, or a power bank in the car, is what turns a flat battery from a crisis into an inconvenience.
Change all the batteries at once and set a calendar reminder for six months. Smart locks warn about low batteries and people ignore the notification, and the lock then fails at the least convenient moment. A scheduled change costs a few pounds a year and removes the problem entirely.
Are smart locks secure?
A good one is as secure as the mechanical lock it replaces, which is what actually resists force. The smart part adds convenience and a new attack surface, so choose a lock with a solid mechanism and keep its firmware updated.
What happens if the batteries die?
Most locks offer a physical key override or external contacts for emergency power. Know which yours has before you need it, and keep the corresponding backup accessible from outside.
Does a smart lock need Wi-Fi?
Not to work. Keypad and fingerprint entry are local. Wi-Fi, through a bridge or built in, adds remote control and notifications, which is convenience rather than function.
Will it fit my door?
Measure the door thickness and backset and identify the lock type before buying. Fit is what rules out most models, and manufacturers publish compatibility checkers for exactly this reason.
Is auto-unlock reliable?
Less so than any other method, because it depends on background location which phones suppress to save battery. Treat it as a bonus and use a code or fingerprint as your primary method.
How to choose
Measure the door and identify the lock type first, and fix any binding before fitting anything. Choose a keypad as the primary method with a phone as a convenience. Prefer built-in Wi-Fi over a bridge if you want remote access. Then set a battery reminder and make sure the physical backup exists and is reachable from outside.
