Smart Locks: Pros, Cons and the Safety Questions to Ask Before You Buy

You’re standing at the front door with groceries in both arms, a dog pulling at the leash, and your keys are somewhere at the bottom of a bag. That moment sells a lot of smart locks. So does the dog walker who needs to get in at noon, the cleaner who comes every other Friday, and the teenager who loses keys every semester.

But a lock is the one smart home device where failure has real consequences. A dead smart bulb is an annoyance. A lock that won’t open, or opens for the wrong person, is a problem. This guide walks through the honest pros and cons, the safety questions people actually ask, and how to pick and set up a lock you can trust.

What a smart lock actually is

A smart lock is a door lock that can be operated electronically, usually through some mix of a keypad, a phone app, a fingerprint reader, a key fob or a voice assistant. Most are deadbolts, because the deadbolt is the lock doing the real security work on a residential door.

They come in 3 broad styles:

• Full replacement deadbolts. You remove the old deadbolt entirely and install a new one with a keypad or touchscreen outside and a motor inside.
• Retrofit locks. You keep your existing exterior deadbolt and keys, and replace only the interior thumb-turn with a motorized unit. Nothing changes outside the door, which matters for renters.
• Smart handle sets and levers. Common on interior doors, side doors and in rentals managed by property companies.

How they connect matters too. Some talk to your phone over Bluetooth only, which works when you’re near the door. Others use Wi-Fi, Z-Wave, Zigbee or Thread, often through a hub or a smart speaker, so you can check or lock the door from anywhere. If you’re still choosing a platform, our guide to how to set up a smart home covers hubs and ecosystems first.

The pros: why people switch

No more keys, or fewer of them. A keypad means nobody in the house needs to carry a key for daily use. Kids can memorize a code. You can’t lose a code down a storm drain.

Guest and service codes. This is the feature most owners end up valuing most. You can give the dog walker a code that only works weekdays from 11 to 2, give a house guest a code that expires Sunday night, and delete the contractor’s code the day the job ends. With a traditional lock, the only way to “revoke” a copied key is to rekey.

An activity log. Most app-connected locks record when the door was locked or unlocked and by which code or user. That’s useful for knowing the kids got home, or confirming the cleaner showed up.

Auto-lock and remote lock. Many models can lock themselves a set time after the door closes, and Wi-Fi or hub-connected models let you lock the door from your phone if you’re not sure you did.

Smart home routines. A lock can trigger other things, such as turning on entry lights when the door unlocks after dark.

The cons: what owners complain about

Batteries. Nearly all residential smart locks run on AA or rechargeable battery packs. Battery life varies a lot by model, connection type and how often the door is used. Wi-Fi locks generally drain faster than Bluetooth or Thread locks. You will get low-battery warnings, but you have to act on them.

Another account to secure. Your lock is now tied to an app account. If that account has a weak or reused password, the weak point is no longer the cylinder but your login.

Connectivity hiccups. Remote features depend on your Wi-Fi or hub. If the internet is down, keypads and Bluetooth usually still work locally, but remote unlocking and notifications may not.

Installation fit. Doors that stick, misaligned strike plates or unusual door thicknesses can make motorized bolts jam or strain, which also drains batteries faster.

Cost. Smart locks cost more than a standard deadbolt, and some brands charge a subscription for extra features such as longer history or advanced integrations.

Safety question 1: what happens when the battery dies?

This is the question everyone asks, and the honest answer is: it depends on the model, so check before you buy.

Most locks give you several weeks of low-battery warnings through the app, the keypad or both. If you ignore them, manufacturers usually provide at least one fallback:

• A physical key cylinder. Many keypad deadbolts still have a hidden or visible keyway. Keep the key somewhere outside the house you can reach, such as with a trusted neighbor, not in the car you lock with the same phone.
• Emergency power contacts. Many keypad locks have contacts on the exterior where you can hold a 9-volt battery, or a USB-C port, to power the keypad long enough to enter your code. Which one your lock uses varies by model.
• Inside access always works. From inside, the thumb-turn opens the lock mechanically on essentially all residential models, so you are not trapped in by a dead battery.

A useful habit: change batteries on a schedule, such as when you change smoke alarm batteries, instead of waiting for the warning. And use the battery type the manual specifies. Some locks are sensitive to rechargeable AA cells, which run at a lower voltage.

Key takeaway: Buy a lock with at least one backup entry method (a physical key or emergency power contacts), store that backup somewhere you can actually reach, and replace batteries on a schedule rather than waiting for the warning.

Safety question 2: can a smart lock be hacked?

Yes, in principle, the same way any connected device can be. Security researchers have found flaws in some smart lock models over the years, and responsible manufacturers patch them through firmware updates. In practice, the realistic risks for most households are more ordinary:

• Account takeover through a reused password or a phishing email. Use a unique password and turn on 2-factor authentication for the lock app.
• Shared codes that never get deleted. The contractor from 2 years ago may still have a working code.
• Weak physical hardware. A lock with a flimsy bolt or a short strike plate screw fails to a kick long before anyone bothers with radio attacks.

On the physical side, look for a deadbolt certified to ANSI/BHMA A156.40, the American standard for residential deadbolts first approved in 2015. It grades locks A, B or C separately for security, durability and finish, so a listing such as “AAA” means top grade in all 3. Grade C still means the lock passed testing.

On the digital side, look for a manufacturer that publishes a security or vulnerability-reporting page and pushes firmware updates. NIST’s IR 8425 sets out baseline cybersecurity capabilities for consumer connected devices, such as secure updates and data protection, and it underpins the FCC’s voluntary U.S. Cyber Trust Mark labeling program. As of fall 2026, the FCC was still setting up the program’s administrators and says it will announce when products can apply, so don’t expect the label on most locks yet. Check the FCC’s program page for its status.

Your home network matters as well. If your lock uses Wi-Fi, follow the basics in our guide to securing your home Wi-Fi.

Safety question 3: can renters use a smart lock?

Often yes, but get permission first. Most leases restrict changing or adding locks, and landlords usually need a way in for emergencies and repairs. State and local rules on landlord access and lock changes vary, so read your lease and check your state’s tenant rules. This is not legal advice.

Renter-friendly approaches:

• Retrofit locks that replace only the interior thumb-turn. The exterior cylinder and the landlord’s key keep working, and you can reinstall the original part when you move out.
• Ask the landlord whether they’ll approve a keypad deadbolt if you give them a code, or whether they’ll install one. Many property managers now use smart locks themselves to handle move-ins and maintenance visits.
• Keep the original hardware in a labeled bag so you can restore the door exactly as it was.

Safety question 4: how should guest access codes work?

Guest codes are the best feature of a smart lock, and also the easiest to get sloppy with. A few rules:

1. One code per person or service, never a shared “guest” code. That way the log shows who entered, and you can remove one person without changing everyone’s code.
2. Use schedules. Recurring codes (weekdays 11 to 2) for regular help, and expiring codes for guests and short-term rentals.
3. Delete codes when the job ends. Put a reminder on your calendar.
4. Avoid obvious codes like 1234, birth years or your street number.
5. Wipe the keypad occasionally. On some keypads, worn or smudged buttons can hint at which digits are in a code. Some locks let you type extra random digits before or after your real code to hide it.

Matter, Aliro and what’s changing

Two standards from the Connectivity Standards Alliance (CSA) are shaping new locks:

• Matter lets a certified lock work with multiple ecosystems, such as Apple Home, Google Home, Amazon Alexa and Samsung SmartThings, instead of being tied to one app. Many Matter locks connect over Thread. Our explainer on what Matter is covers how it works, and our Alexa vs Google Home vs Apple HomeKit comparison can help you pick a platform.
• Aliro is a newer CSA standard for using a phone or watch as a digital key. The CSA released Aliro 1.0 on February 26, 2026. It covers tapping with NFC, Bluetooth Low Energy for longer range, and ultra-wideband for hands-free entry, with Apple, Google and Samsung among the companies that have said they’ll support it in their wallets. Expect support to roll out gradually across new locks and phones; check a lock’s listing for Aliro certification rather than assuming it.

Where to start: choosing and setting up a smart lock

1. Check your door. Measure door thickness and backset, and make sure the existing deadbolt turns smoothly with the door closed. Fix sticking doors first.
2. Decide on retrofit or replacement. Renters and anyone who wants to keep their existing keys should look at retrofit models.
3. Pick your ecosystem and connection. Bluetooth-only is simplest; Wi-Fi, Thread or a hub adds remote control. Matter certification gives you more flexibility later.
4. Look for a tested deadbolt. Check for an ANSI/BHMA A156.40 grade on the box or spec sheet.
5. Confirm the backup. A key cylinder, emergency power contacts or both.
6. Secure the account. Unique password, 2-factor authentication, and turn on automatic firmware updates.
7. Set up codes properly. One per person, schedules for regular visitors, and a calendar reminder to clean up codes.
8. Use a longer strike plate screw. If your strike plate is held by short screws, longer screws into the frame make the door much harder to kick in, smart lock or not.

If installation isn’t something you want to tackle, a locksmith can help; our piece on how technology is changing locksmiths explains what modern locksmiths now handle.

The bottom line

Smart locks are genuinely useful, mostly because of guest codes, activity logs and not needing keys. Their weak points are predictable: batteries, account security and poor installation. Buy a lock with a tested deadbolt and a backup way in, lock down the app account, and treat codes like keys you actually have to collect back. Do that, and a smart lock is at least as safe as the deadbolt it replaced, and a lot more convenient. For more terms like Thread and Z-Wave, see our glossary.

Sources

• Builders Hardware Manufacturers Association: ANSI/BHMA A156.40 Residential Deadbolts — the residential deadbolt standard and its A/B/C grades
• Connectivity Standards Alliance: Introducing Aliro 1.0 — Aliro 1.0 release date, NFC, BLE and UWB support
• FCC: U.S. Cyber Trust Mark — voluntary IoT labeling program and its current setup status
• NIST IR 8425: Profile of the IoT Core Baseline for Consumer IoT Products — baseline security capabilities for consumer connected devices