Smart Locks: Which Ones Work on a Rental Door, an Old Deadbolt, or Without Wi-Fi

By the Home Security Systems & Alarms editorial team · Research-based (no hands-on testing) - see how we evaluate · Last updated September 14, 2026

This page answers three questions that the product pages bury: will it go on a door I do not own, will it go on a door built before smart locks existed, and does it need Wi-Fi to work? Every price and every specification below was read on the maker's own US page on the date shown. We have not installed or tested these locks; this is a documented comparison of what each company publishes, not a review of build quality, app reliability or how the lock feels in the hand. Where a company publishes no price on its own site, we say so instead of borrowing a figure from a retailer.

If you are earlier in the process and have not decided what kind of system you want, start with how to choose a home security system. If you rent, the rules that govern what you may install are covered separately in what a landlord can and cannot restrict.

The three fit questions, in order

1. Does it replace your deadbolt, or sit on top of it?

This is the fork in the road, and it decides almost everything else.

• Retrofit (inside only). The unit screws to the inside of the door in place of the thumbturn and turns the deadbolt you already have. August describes its lock as attaching "right to the existing lock on the inside of your door so you can continue to use your existing keys," and Yale describes the Approach as installing "on the inside of your door without replacing your existing deadbolt, so you can keep your keys." Nothing changes on the street side. No new holes. The existing key still opens the door, which matters if a landlord, a building manager or a family member holds one.
• Replacement (whole deadbolt). The old deadbolt comes out and the new one goes in, usually with a keypad on the outside. You get code entry without a phone, a published BHMA security grade, and in some cases Apple Home Key. You also inherit a fitting problem: the new lock has to match your door.

2. Will it physically fit?

For a replacement lock, three measurements decide it. Schlage publishes them for the Encode Plus: the lock "fits standard doors with 1-3/8 in. to 1-3/4 in. door thickness and 2-3/8 in. or 2-3/4 in. backset," with a universal backset that adjusts between the two. Backset is the distance from the edge of the door to the centre of the bore hole, and it is the measurement people get wrong. Old, custom, fire-rated and some steel doors fall outside these ranges, and that is when a replacement lock arrives and will not go on.

For a retrofit lock, the fit question is narrower but absolute: it needs a single-cylinder deadbolt, meaning key outside, thumbturn inside. August states the requirement plainly in its specifications and, like Yale, publishes a compatibility checker for the interior hardware. If your door has a deadbolt that takes a key on both sides, no retrofit lock on this page will work, because there is no thumbturn for it to hold.

3. What does it talk to?

Three answers, and only one of them needs your router.

• Built-in Wi-Fi. Remote lock, unlock and activity alerts from anywhere, no extra box. August's current lock and Schlage's Encode family do this. It also means the lock is an internet-connected device on your network, which is worth treating with the same care as a camera.
• Bluetooth only. The app works when your phone is near the door and not otherwise. Kwikset's Aura page is explicit: you can lock or unlock "using the Kwikset App within Bluetooth range of your lock." For a lot of households that is all a smart lock was ever needed for, and it removes the remote-access attack surface entirely.
• A hub. Z-Wave locks such as the Schlage Connect join a home automation system rather than your Wi-Fi. Schlage describes the Connect as combining "the enhanced security of Z-Wave Plus" for connecting "to your home automation system," which means you need that system first. This is the route people already running Home Assistant or a similar local hub usually want.

In all three cases the keypad or the key still opens the door when the network is down. A smart lock's connection is how you supervise it, not how it works.

Lock by lock: what each one does to your door (read 2026-09-14)

Prices are the list or regular prices shown on each maker's own US site on 2026-09-14. Sale and coupon prices were excluded. Blank cells mean the company did not publish the figure on the page we read, not that the feature is missing.

If you rent

A retrofit lock solves the landlord problem almost completely, and it is worth understanding exactly why. The lock never touches the outside of the door. The cylinder, the keyway and every key already cut for that door keep working, so the building's master key or the landlord's copy is unaffected. Nothing is drilled. At move-out you undo the mounting plate, screw the original thumbturn back on, and the door is as you found it. Yale markets the Approach on exactly this basis, calling it "the perfect choice for renters or first-time smart lock users," and August's product page describes its lock as "renter friendly with minimal assembly."

Three cautions that the marketing does not cover.

• Read the lease before you buy, not after. A lease can restrict alterations and devices even when the change is reversible, and some leases specifically address door hardware. Our guide to what a landlord can and cannot restrict sets out where the line usually falls and why anything touching a shared corridor or the exterior is treated differently from the inside of your unit. That page is general information, not legal advice, and so is this one.
• A retrofit lock is not a security upgrade. It automates the deadbolt you already have. If that deadbolt is worn, poorly fitted or anchored in a soft strike plate with half-inch screws, a smart lock changes nothing about how the door resists force. A $15 box of 3-inch strike plate screws does more for a weak frame than any lock on this page, and you can take the old screws with you.
• Keep a physical key on you. Batteries die. Every retrofit lock here leaves the keyway working precisely so that this is a non-event, which is an argument for the retrofit route in a building where you cannot simply call a locksmith and be let in.

If drilling is the constraint across your whole setup and not just the door, the same logic applies to sensors and cameras: see apartment security without drilling and the wider renter-friendly security guide.

If your door is old

Old doors fail smart locks in predictable ways. Before you order anything that replaces the deadbolt, spend five minutes with a tape measure.

• Door thickness. Measure the edge of the door. Schlage's published range for the Encode Plus is 1-3/8 in. to 1-3/4 in. Older solid doors, and doors that have been planed or re-faced, can sit outside it.
• Backset. Measure from the edge of the door to the centre of the existing deadbolt hole. Schlage's Encode Plus adjusts to 2-3/8 in. or 2-3/4 in. If yours is neither, a standard replacement deadbolt will not line up with the hole in your door frame.
• Bore hole. The round hole through the face of the door. If it is smaller than the new lock requires, fitting means enlarging it, which in a rental is out of the question and in an old door is a job worth handing to a locksmith.
• Single or double cylinder. Look at the inside of the door. A thumbturn means single cylinder and every option here is open to you. A keyhole on the inside means double cylinder, and no retrofit lock will fit.
• Does the deadbolt throw cleanly today? If you have to lift or shove the door to turn the key, the door has dropped or the frame has moved. A motor will struggle where your hand does, and you will get failed-lock alerts rather than a working lock. Fix the alignment first.
• Is there a storm door or a deep trim? Retrofit units add depth on the inside. August publishes a 46 mm depth for its lock. Check that the interior unit clears anything mounted nearby before you buy.

If the measurements come back non-standard, the retrofit route is not a compromise, it is the correct answer: the mechanism staying in the door is the one already fitted to it.

If you do not want the lock on the internet

There is a reasonable position that a door lock should not be reachable from outside the house at all, and the market still serves it.

Bluetooth only. The Kwikset Aura is controlled from the app only when the phone is in Bluetooth range, and it stores up to 250 user codes on the lock itself. There is no remote unlock because there is no remote anything. The trade is that you cannot let a contractor in from the office, and you cannot see the activity log while you are away.

Hub, not router. A Z-Wave lock such as the Schlage Connect joins a home automation controller. Whether that setup reaches the internet is your choice rather than the lock maker's, which is the main reason local-first smart home users prefer it. It only makes sense if you already run a hub, and Z-Wave locks are usually a poor first purchase for someone who does not.

Codes and nothing else. Every keypad lock above opens with a code with no app involved. If the goal is to stop hiding a key under a pot for the dog walker, a keypad lock with no account and no radio traffic already does that job.

One point in the other direction, for honesty. A lock that never connects also never tells you it was opened. The activity log is the feature that turns a lock into a security device rather than a convenience, and it is the thing you give up first. Decide which of the two you were buying.

Who each one suits

What a smart lock does not do

Worth saying plainly, because the category is sold as a security product and is mostly a convenience product.

• It does not make the door harder to force. Frame, strike plate, screws and hinges decide that.
• It does not replace an alarm. A lock knows its own state; it does not know a window opened. If you want a door opening to trigger something, that is an entry sensor and a system, covered in how many door and window sensors you need.
• It does not tell a monitoring centre anything unless it is integrated with a monitored system, which most of these are not.
• It does not remove the need to think about who has a code. Codes get shared the way keys get copied, and the fix is the same: audit and remove them.

What it does do is end the hidden-key problem, give you a dated record of who came and went, and let you stop wondering at 11pm whether you locked up. Those are real, they are just not the same thing as burglary resistance.

About this comparison

Every figure above was read on the maker's own US page on 2026-09-14, in a browser, and recorded in our pricing log. We excluded sale, coupon and promotional prices and quoted list, regular or MSRP prices only. Where a company publishes no price on its own site (Kwikset) or its product pages did not load on the read date (Level), we say so rather than repeating a figure from a retailer or another review site. We do not perform hands-on testing and make no claim about build quality, motor reliability, real-world battery life or app behaviour; see our methodology and editorial policy. Nothing here is legal advice about a lease. Substantive changes to this page are listed on our corrections page.

Sources

• August - Wi-Fi Smart Lock product page (price, retrofit install over existing deadbolt, keeps existing keys, single-cylinder deadbolt requirement, built-in Wi-Fi 2.4/5 GHz, 2 x CR123, DoorSense, 72 mm diameter and 46 mm depth, "renter friendly with minimal assembly", Yale Keypad Touch accessory price) (accessed 2026-09-14)
• Yale Home - Yale Approach Lock with Wi-Fi product page (price, retrofit install without replacing the existing deadbolt, "keep your keys as a backup", compatible with most single-cylinder deadbolts, included Yale Connect, optional Yale Keypad, renter positioning) (accessed 2026-09-14)
• Schlage - Encode Plus Smart WiFi Deadbolt, Camelot trim (MSRP, door thickness 1-3/8 in. to 1-3/4 in., backset 2-3/8 in. or 2-3/4 in., 4 x AA and up to six months typical use, one physical backup key, up to 100 access codes, BHMA rating, Apple Home Key) (accessed 2026-09-14)
• Schlage - Encode Smart WiFi Deadbolt overview ("From $299", built-in Wi-Fi with no additional accessories) (accessed 2026-09-14)
• Schlage - Connect Smart Deadbolt, Z-Wave Plus overview ("From $241", Z-Wave Plus S2, connects to a home automation system) (accessed 2026-09-14)
• Kwikset - Aura Bluetooth Enabled Smart Lock product page (Bluetooth-range control via the Kwikset App, up to 250 user codes, traditional keyway, SmartKey Security rekeying; no price published, "Where to Buy" only) (accessed 2026-09-14)
• Level - product navigation listing Level Bolt $199, Level Lock $249 and Level Lock Pro $349 with one-line descriptions. The Level Bolt detail page and the Level comparison page both returned "Page not found" on the read date (accessed 2026-09-14)