Smart Locks 101: Replace, Retrofit, or Skip

Prices in this article are typical U.S. retail, checked October 2026.

Section 1: Why is the front door the one device that has to work? (Introduction)

A smart lock is a door decision first: replace the deadbolt, retrofit the interior thumb-turn or skip it. Choose by door type, lease rules and whether you need a keypad, Home Key or remote access, and who else needs a key.

Every smart device in the house can fail politely. A bulb that will not dim is an annoyance; a thermostat that loses Wi-Fi still heats. The front door is different. It is the one device that has to work at 3 a.m., in the rain, with a dead phone and a sleeping house.

That is the lens for this guide. A smart lock is not a gadget you judge by its app. It is a mechanical deadbolt with a radio attached, and the mechanical part matters more than the radio. The best smart lock is the one whose battery, keyway, and bolt still make sense when the network is gone.

The category has also become confusing. Some locks replace the whole deadbolt. Some bolt onto the inside of the door you already have. Some are levers, some are keypads, some are both, and the prices run from about $100 to more than $300. This guide separates the three designs, explains what the security grades actually measure, covers power and protocols, and ends with a buying sequence. For the wider device picture, start with the Devices hub.

Section 2: Which of the three lock designs fits your door?

There are three ways to add intelligence to an entry door, and they are not interchangeable.

Replace the deadbolt

The most common design is a full deadbolt replacement: you remove the existing deadbolt and install a new one with a keypad, a radio, and a motor inside. Yale’s Assure Lock 2 is the mainstream example, with Bluetooth built into every model and Wi-Fi or Z-Wave versions above it. Schlage’s Encode line is the same idea with a touchscreen and a built-in alarm.

This design gives you the most features: keypad codes, auto-lock, access logs, and often a physical key as backup. It also asks the most of your door. You need a standard prep — a 2-1/8-inch bore hole and a 1-inch edge bore — and a door thickness between 1-3/8 and 1-3/4 inches, which covers most U.S. entry doors. The backset, the distance from the door edge to the center of the bore hole, must be 2-3/8 or 2-3/4 inches; better locks adjust to both.

Retrofit the deadbolt you have

A retrofit lock leaves the outside of the door alone. You keep your existing key and cylinder, and a motorized unit mounts on the interior side to turn the thumb-turn. August’s Wi-Fi Smart Lock is the best-known example, and Level’s Bolt is the hidden version that fits inside the door.

The appeal is obvious: no new keys, no cylinder to re-key, and a five-minute install with a screwdriver. The trade is that the outside of the door does not change, so there is no keypad unless you add one, and the lock inherits whatever cylinder and bolt the door already had. For renters, that is often the deciding factor. If you cannot change the hardware, a retrofit is the only option that does not require the landlord’s blessing.

The lever and the second door

Lever-style smart locks exist for doors that use a lever rather than a deadbolt: a side door, a garage entry, a back door with a handle set. They are convenient and usually cheaper, but a lever latch is a weaker security target than a deadbolt. Use them for the mudroom, not the front door.

The side door is worth a mention because it is the most common gap. A house with a $300 lock on the front and a builder-grade knob on the back has one smart lock and one easy door.

Section 3: Does a smart lock actually make the door safer?

A smart lock does not automatically make a door safer. The lock is one part of an assembly: the bolt, the strike plate, the frame, and the door itself. Consumer Reports’ lock testing is blunt about this. Its testers found that a few well-placed kicks or a couple of minutes with a cordless drill defeat almost every lock in its ratings. At least half of the models failed the first round, and the retest with a reinforced box strike plate improved security for any lock.

That finding is the most useful thing in the category. The strike plate — the metal plate on the door frame that receives the bolt — is often held by two short screws into soft wood. A reinforced plate with long screws into the stud behind the frame is a cheap upgrade that improves any lock, smart or not. Do that before you spend the extra $100 on a brand.

What the grades mean

Locks are graded under ANSI/BHMA standards, and the grades are about durability and physical attack, not app features. BHMA defines three progressive levels, with Grade 1 the highest and Grade 3 the minimum residential rating. The tests count cycles, hammer blows, and torque, so a Grade 1 deadbolt is built for commercial use and a Grade 3 is what many builders install.

The labels are easy to misread. Schlage, for example, certifies the Encode Plus as “Grade AAA in Security, Durability and Finish” under the residential deadbolt standard (A156.40) and as “Commercial Grade 1” under A156.36. Those are two different standards with two different scales, and both are top-of-scale claims. When you compare locks, compare the standard cited, not the letter.

What smart adds, and what it does not

Smart features help with the things mechanical locks are bad at: knowing who came in, giving a cleaner a code that expires, locking the door you forgot. They do not stop a determined intruder with a drill, and they introduce their own failure modes: a dead battery, a jammed motor, an app that will not connect.

The honest framing: a smart lock improves convenience, auditability, and access control. It does not turn a hollow-core door into a vault. If physical security is the actual goal, spend first on the strike plate, the frame, and the door, then on the lock.

Section 4: Which radio, battery and offline test should you check?

The four radios

• Bluetooth is in almost every smart lock and needs no hub, but it only works within range of the door. It is fine for phone-as-key and for setup.
• Wi-Fi connects directly to the router, so you can lock and unlock from anywhere without a bridge. It costs battery, because the radio has to stay associated. Schlage’s Encode Plus specifies a 2.4 GHz network, and 2.4 GHz is the band most locks require.
• Thread is a low-power mesh that needs a border router — a HomePod, an Apple TV, or a compatible hub. It is the battery-friendly path to Matter.
• Z-Wave is the older low-power mesh for hubs like SmartThings or Home Assistant. It is reliable and needs a hub with a Z-Wave radio.

Matter matters here because it is the standard that lets one lock work with several ecosystems at once, rather than one vendor’s app. Locks are one of the device types Matter covers, and a Matter lock plus a border router is the most future-proof combination — if the feature set you need is supported. For the credential side — Home Key, NFC and Aliro — see What Is Aliro?.

Battery life is the spec that matters

August rates its Wi-Fi lock at up to three months per set of batteries; the company’s own support page suggests that is typical, not worst case. Wi-Fi locks generally run shorter than Bluetooth or Thread models because the radio is always on. A keypad with a backlight and a camera-adjacent feature set runs shorter still.

Treat battery life as a design constraint, not a footnote. A lock that dies every two months trains you to ignore the low-battery warning. Prefer the model with the longer rating, use lithium cells if the manufacturer allows them, and set a reminder at 80 percent.

The auto-unlock trade-off

Auto-unlock is the feature people love and then turn off. The lock watches your phone’s location and retracts the bolt as you arrive. Done well, it is genuinely nice with an armful of groceries. Done badly, it unlocks when you are already inside, or when your phone drifts to the edge of the geofence and back. Test it for a week with notifications on before you rely on it, and keep the keypad as the fallback.

The offline test

Before you trust a lock, test it without the network:

1. Unplug the router or disable Wi-Fi.
2. Lock and unlock with the keypad.
3. Lock and unlock with the physical key.
4. Check whether scheduled codes still work. Some locks store schedules on the lock; others fetch them from the cloud, and a guest code that only exists online fails when the internet does.
5. Let the battery run low, if you can, and confirm the warning appears before the motor refuses.

If the keypad and the key work offline, the lock is a lock. If they do not, it is an app with a bolt attached.

Section 5: What does a smart lock cost?

Those are list prices from the manufacturers, and they move with sales and finishes. The pattern is consistent: you pay about $70 for Wi-Fi over Bluetooth in the same line, and another $90 for the top trim and Apple home key support.

Installation is usually free if your door has a standard prep, because the swap is a screwdriver job. It stops being free if the door is metal, the bore is nonstandard, or the existing deadbolt is integrated into a handleset. A locksmith call is $100 and up, which can exceed the price difference between tiers.

Two costs hide in the category. A hub or bridge may be required for Bluetooth-only or Z-Wave locks, and it is easy to miss on the product page. A subscription is rare for locks — most include remote access and logs in the price — but check before assuming.

Section 6: What is the buying sequence, and who should skip it? (Conclusion)

1. Fix the frame first. A reinforced strike plate with long screws, and a solid door, do more for security than any radio. Do this before shopping.
2. Choose the design by your constraint. Replacing the deadbolt gives the most features; a retrofit is the renter’s route and keeps your keys; a lever lock belongs on the side door.
3. Choose the radio by your hub. Wi-Fi for standalone simplicity, Thread plus a border router for battery life and Matter, Z-Wave if you already run that mesh.
4. Verify the fit. Measure door thickness and backset, and confirm the lock supports both 2-3/8 and 2-3/4 inches.
5. Run the offline test. Keypad, key, and scheduled codes with the router unplugged. Then set a battery reminder.

Some homes should skip the category. If you live in an apartment with a landlord-managed lock, a $200 retrofit may not be allowed, and a $40 keypad safe is a better spend. If your door is the original hollow model with a failing frame, a smart lock is decorating a weak point. And if you never give out codes and never forget to lock up, the convenience is real but small.

The lock is the one device where “it works when everything else fails” is the whole point. Buy for that night, not for the demo.

Household reality

A keypad code lets a guest in without an app, and the physical key still works when the battery dies. Auto-unlock is the feature most likely to unsettle a household; leave it off until everyone agrees. Add every adult to the lock before the first guest arrives. If the app stops reaching it, the Bluetooth guide starts with range and permissions. In an apartment, the no-drilling lock guide covers the retrofit options.

Where to buy

Related reading

• Smart Locks for Guest Access — codes, schedules, and the cloud dependency.
• Renting a Smart Home — what you can change without permission.
• Home Security Systems 101 — where the lock fits in the alarm.
• Choosing a Smart Home Ecosystem — the platform decision underneath.

Sources

• Consumer Reports: Best Door Locks of 2026 — kick and drill testing, strike-plate findings, updated August 2026
• BHMA Product Grade Levels — Grade 1–3 definitions and progressive performance benchmarks, checked October 2026
• Schlage Encode Plus — A156.40 Grade AAA and A156.36 Commercial Grade 1 certifications, 2.4 GHz Wi-Fi, backset and door thickness specifications, checked October 2026
• August Wi-Fi Smart Lock — $199.99, retrofit design and up to three months of battery life, checked October 2026
• Yale Smart Locks — Assure Lock 2 keypad at $169.99 and Wi-Fi model at $239.99, checked October 2026
• Schlage Encode Plus listing — Encode Plus from $329, checked October 2026