Smart Locks: How to Choose One, Install It and Keep Your Door Secure
A smart lock lets you open your door with a code, your phone or a fingerprint, share access with guests and see who came and went. This guide explains the types of smart locks, how they connect, what security grades mean, how to check your door before buying, and the settings that keep a smart lock secure.
Quick answer
A smart lock lets you open your door with a code, your phone or a fingerprint, share access with guests and see who came and went. This guide explains the types of smart locks, how they connect, what security grades mean, how to check your door before buying, and the settings that keep a smart lock secure.
In this article
A smart lock replaces or upgrades the deadbolt on your door so it can be opened with a code, an app, a fingerprint or your phone's proximity. The everyday benefits are real: no more hiding a key under the mat, letting in a dog walker remotely, getting an alert if the door is left unlocked. But a lock is still a lock first. The right smart lock is the one that fits your door, works with your home setup and is at least as physically strong as what it replaces.
The main types of smart locks
- Full deadbolt replacement. Replaces both the interior and exterior parts of your deadbolt, usually with a keypad or touchscreen outside. This gives the most features, including code entry.
- Retrofit lock. Replaces only the interior thumb-turn of your existing deadbolt. Your current exterior keyhole and keys keep working, which makes retrofits popular with renters and anyone who wants to keep matching keys.
- Smart handle or lever set. Combines a lever handle with a locking mechanism, common on side and garage doors, and on doors that do not have a separate deadbolt.
- Smart keypad add-ons. Some systems pair a separate keypad, mounted outside, with a retrofit lock inside.
How smart locks unlock
| Method | How it works | Worth knowing |
|---|---|---|
| Keypad code | Enter a PIN on the exterior pad | Easy to share temporary codes; wipe the pad occasionally so worn keys do not hint at your code |
| Phone app | Tap to lock or unlock, nearby or remotely | Remote control needs Wi-Fi or a hub |
| Auto-unlock | Uses your phone's location to unlock as you arrive | Convenient, but test it; misfires can happen near the door |
| Fingerprint | Built-in sensor on the exterior | Fast for regular household members; register several fingers |
| Phone or watch tap | Digital key stored in a wallet app on supported phones | Only works with compatible lock and phone combinations |
| Physical key | Traditional key cylinder | A useful backup; some keyless models omit it entirely |
How smart locks connect
Connection type decides whether you can control the lock from away, how long the batteries last and which smart home system it joins.
- Bluetooth works directly with your phone at close range. Battery-friendly, but remote access needs a separate bridge or hub.
- Wi-Fi allows remote access without a hub, but typically drains batteries faster.
- Z-Wave and Zigbee are low-power protocols that need a compatible hub, often used in professionally installed or hobbyist systems.
- Thread with Matter is the newer standard designed to work across ecosystems, with low power use and local control. Our explainer on Matter and Thread covers why it matters for devices like locks.
Before buying, confirm the lock supports the platform you already use, whether that is Amazon Alexa, Google Home, Apple Home or something else. Our guide to choosing a smart home ecosystem explains the differences.
Physical security: check the grade
The most reliable sign of a lock's strength is its ANSI/BHMA grade, a rating from American testing standards that covers durability, strength and resistance to attack:
- Grade 1: the highest, common in commercial buildings.
- Grade 2: a solid level for residential doors.
- Grade 3: the basic residential level.
Not every smart lock is graded, and some list only partial certifications. If a lock does not state a grade, ask the manufacturer. Equally important is the hardware around the lock: a reinforced strike plate fastened with long screws that reach the door frame's stud does more to resist a kicked-in door than any smart feature.
Check your door before you buy
- Measure the backset, the distance from the door edge to the center of the deadbolt hole. Most US doors use one of two standard sizes, and most locks support both, but confirm.
- Measure door thickness. Very thin or very thick doors may need an adapter kit.
- Test the bolt. Lock the existing deadbolt with the door open, then closed. If you have to push or lift the door to make the bolt slide, a motorized lock will struggle and drain batteries. Adjust the strike plate or hinges first.
- Check the interior space. Retrofit and motorized units are bulky; make sure they do not hit a door handle or trim.
- Consider weather. Exterior keypads on doors exposed to rain, direct sun or extreme cold need appropriate weather ratings.
- Look for Wi-Fi coverage near the door if you choose a Wi-Fi model or bridge.
Installation of most residential smart locks needs only a screwdriver and the manufacturer's app. Allow time for calibration, which teaches the motor how far to turn.
Settings that keep a smart lock secure
- Protect the account. Use a unique, strong password and turn on two-factor authentication for the lock's app; access to the account is access to your door. Prefer an authenticator app or passkey over text-message codes where the app supports them.
- Use individual codes. Give each person or service their own code so you can remove one without changing everyone's.
- Schedule guest access. Set codes that work only during certain hours or expire after a date.
- Turn on auto-lock after a short delay, and enable door-left-unlocked alerts.
- Install firmware updates promptly; enable automatic updates if offered.
- Review the activity log occasionally and remove old users.
- Check privacy settings. Lock apps record when the door was used and by whom. Read what the company stores and shares, and remove the lock from your account and factory-reset it before selling or moving out.
Batteries and power failures
Most smart locks run on AA batteries or a rechargeable pack. Expect a warning in the app before they run out, and replace them promptly. A Wi-Fi outage usually only removes remote features; the keypad and Bluetooth typically keep working locally. Find out what your lock offers as a backup, whether a physical key, external battery terminals or both, before you are standing outside in the cold.
Smart locks for renters and shared homes
Renters should get written permission before changing any lock and keep the original parts. Retrofit models are the least invasive choice. In shared homes and short-term rentals, the ability to issue and revoke codes is often the most valuable feature of all, and many owners pair a lock with a doorbell camera for a clear view of who is at the door.
A smart lock is worth it when it removes small daily frictions without weakening your door. Start with fit and physical strength, pick a connection that matches your smart home, and secure the account as carefully as you would the keys themselves.
Frequently asked questions
What happens if a smart lock's batteries die?
Most smart locks warn you in the app and with a light or sound well before the batteries run out. Many keep a physical key cylinder as a backup, and some keypad models have terminals that let you power the lock briefly from an external battery to enter a code. Check which backup your model offers before you rely on it.
Can I install a smart lock if I rent?
Often, but ask your landlord first, since many leases restrict changing locks. Retrofit smart locks that replace only the interior part of an existing deadbolt are popular with renters because the outside key still works and the original part can be reinstalled when you move out.
Are smart locks easier to break into than regular locks?
Most break-ins involve force or an unlocked door, not hacking, so the strength of the deadbolt, strike plate and door frame matters most. A smart lock with a good physical security grade, kept updated and protected by a strong account password with two-factor authentication, can be as secure as a conventional deadbolt and adds activity logs and auto-locking.
