Retrofitting Existing Deadbolts with Smart Lock Conversion Kits for Renters

Intro: Why Renters Should Retrofit Instead of Replace

Related products: Kwikset Convert Smart Lock Conversion Kit with Zigbee

The Replacement Problem

Most leases forbid changing the door, and a full smart-lock replacement is exactly that: it swaps out the entire deadbolt assembly, including the exterior keyway, which means drilling into the door and possibly a new hole in the frame (govelocks.com). For a renter, that's a deposit risk and often a lease violation in one move.

The Retrofit Alternative

A smart lock conversion kit sidesteps the problem entirely. Instead of replacing the deadbolt, the kit mounts over the existing lock's interior thumbturn and adds an electronic actuator on the inside of the door — the existing bolt, latch, and key cylinder keep doing the mechanical work (Kwikset Support). The Kwikset Convert was designed precisely for this situation: in apartment units, you must keep the existing deadbolt so property owners retain key access, and the conversion box lets you add smart features without touching the exterior (CEPRO).

What This Guide Covers

This guide covers which standard deadbolts a conversion kit will fit, how a no-drill installation works, and how to choose between Z-Wave (as in the Convert's radio variants) and Bluetooth (as in the Danalock module) for a renter's setup — so you can add a smart lock to a rental and remove it without a trace.

How a Smart Lock Conversion Kit Works

Related products: Kwikset Convert Smart Lock Conversion Kit with Zigbee · Danalock V3 HomeKit Smart Lock

What the Kit Actually Replaces

A smart lock conversion kit does not replace the deadbolt. It mounts over the interior thumbturn of your existing lock and adds an electronic actuator — a small motorized arm that does the turn the thumbturn used to do. The bolt, latch, and key cylinder keep doing all the mechanical work, exactly as before (Kwikset Support). Effectively, the kit adds an app-controlled motor on the inside of the door while the deadbolt itself stays the same lock your landlord installed.

Coupling to the Tailpiece

Installation is confined to the door's interior face. With a single screwdriver, you remove only the interior thumbturn, then clamp or screw the smart unit onto the inside plate — the exterior keyhole and housing are never touched, and no new holes are drilled in the door or frame (Gove Locks). The retrofit couples mechanically to the lock's tailpiece: Danalock's US manual instructs installers to "remove the inside thumb-turn, leaving just the deadbolt and tail-piece remaining," after which the module engages the same spindle the thumbturn used to turn (Danalock V3 US manual). The Kwikset Convert works the same way: small screws secure its interior assembly to a mounting plate, and the assembly can be un-screwed and reinstalled the same way whenever you need it off the door (Kwikset Support).

What Stays the Same

Because the door's exterior hardware is never modified, the original key — including the landlord's — keeps working from outside, and a manual thumb-turn or mechanical override remains inside for when batteries die or the app can't reach the lock (CEPRO). One caveat worth knowing up front: the Danalock Universal Module V3 is a different class of device. It drives electric door hardware such as garage doors, door strikes, and magnetic locks — not a standard residential deadbolt (Danalock brochure).

Compatibility: Which Deadbolts a Retrofit Kit Will Fit

Related products: Kwikset Convert Smart Lock Conversion Kit with Zigbee

Three mechanical checks decide fit

Because a conversion kit mounts inside the door and drives the existing bolt, compatibility is decided by door hardware, not by electronics. Three questions matter:

1. Is it a mechanical deadbolt? The Kwikset Convert "is only compatible with Mechanical Deadbolts" — Kwikset's own support content states it explicitly, and it "will not work with the Halo Touch," Kwikset's electronic lever. If your rental lock is already a smart or electronic unit, a retrofit kit is the wrong tool.
2. Does it use a conventional thumb-turn and tailpiece? Retrofit kits either replace or couple to the interior thumb-turn. Danalock's U.S. installation manual tells installers to "remove the inside thumb-turn, leaving just the deadbolt and tail-piece remaining," and the module then couples directly to that tailpiece.
3. Does the lock's cylinder family have a kit adapter? Cylinder shape is the difference between "fits" and "doesn't." The Kwikset Convert is built for the conventional square-recess U.S. deadbolt — Kwikset names the 158 Square Deadbolt as a confirmed match — while the Danalock V3 line achieves global reach through country-specific adapters covering the three most common cylinder types: Scandi oval, drop-in (U.S.), and euro profile.

Door thickness and torque-blade match

Two more physical dimensions decide whether a kit will actually mate with your door:

• Door thickness. The Kwikset Convert's interior box fits doors from 1-3/8" to 1-3/4" thick; outside that range, the kit will not align correctly.
• Torque-blade shape. The Convert ships with three torque-blade adapters to match the shape of your existing lock's actuator. If none of the three adapters engages your lock, no amount of screwing will make the retrofit work — measure and match before installing.

Watch for a similar-sounding device that doesn't convert deadbolts

One catalog trap for renters: the Danalock Universal Module V3 is a different class of product. Per Danalock's own brochure, it drives electric door hardware — garage doors, door strikes, electromechanical or magnetic locks — rather than converting a standard residential deadbolt. If your rental entry uses an electric strike or mag lock, that's a genuinely different (and compatible) scenario; if you have an ordinary deadbolt, the Universal Module is not the product you want.

Verify before you buy

Kwikset maintains a dedicated "What locks are supported by Kwikset Convert?" support page with the full compatibility list — check your exact lock model there before purchasing. The universal rule is simple: start from a standard mechanical deadbolt with a working key cylinder and a working interior thumb-turn, exclude anything electronic, match the cylinder family and door thickness, and confirm the specific model on the vendor's list.

Source: Kwikset Support — Convert (Zigbee) product detail Source: Danalock V3 BT U.S. manual Source: Danalock V3 product page Source: Danalock Universal Module manufacturer brochure Source: CEPRO — Kwikset Convert Z-Wave review Source: Kwikset Support — What locks are supported by Kwikset Convert?

Renter-Friendly Installation Without Drilling

Related products: Kwikset Convert Smart Lock Conversion Kit with Zigbee

The single biggest lease-breaker for renters is the drill. A full smart-lock replacement swaps out the entire deadbolt, including the exterior keyway, which often means new holes in the door or frame [Gove Locks]. A retrofit conversion kit sidesteps this entirely: it mounts over the interior of your existing deadbolt, so the only hardware you touch is the inside thumbturn. The exterior keyhole, strike plate, and door face are never modified — no new holes, no repairs, no deposit disputes [Gove Locks].

A screwdriver-only, under-10-minute job

Thumbturn-adapter retrofits are widely described as quick, single-tool installs. The standard sequence is: unscrew the interior thumb turn, attach the mounting plate over the existing interior plate, add the smart lock, and pair it — all with one screwdriver, typically in under 10 minutes [August Home]. With the Kwikset Convert, the interior assembly fastens to the mounting plate with small screws only, and because both sides are just screws, the assembly can be un-screwed from the door and reinstalled the same way — handy if your hub requires pairing within 12 inches (305 mm), per Kwikset's own support guidance [Kwikset Support]. That reversibility cuts both ways: it's also exactly why removal at move-out is trivial.

Why landlords say yes

Because the exterior is never changed, your original key — including the landlord's — continues to work from outside, keeping emergency-entry clauses and lease terms intact [Gove Locks]. Renter guides rate landlord approval for retrofits as "very high" on this basis, versus "low" for keypad-replacement deadbolts that alter the door's appearance [Gove Locks].

Making move-out deposit-safe

Reversibility is a promise; these habits turn it into a guarantee. Immediately save every original screw, washer, and the thumbturn itself in a labeled zip-lock bag. Take "before" photos of the escutcheon, door edge, and strike plate. Place a strip of blue painter's tape where the metal plate rests to prevent micro-scratches, and if your deadbolt feels stiff, work dry lubricant — not oil — into the bolt before mounting so the motor isn't strained. Then run a move-out reversal test right after installing: confirm you can strip the kit back to a stock deadbolt in under 10 minutes [Gove Locks].

Two caveats before you buy

First, check the lease — even fully reversible hardware changes usually need landlord awareness or permission, and the door itself must match the kit's requirements before purchase [Lockin]. Second, remember that no amount of install finesse works around battery life: these kits are battery-only, so keep the physical key and watch low-battery alerts to avoid a lockout that a smart lock can't solve [Gove Locks].

Z-Wave vs Bluetooth: Choosing the Right Retrofit Radio

Related products: Danalock V3 Z-Wave Plus Smart Lock, Gen5

Once you've confirmed your deadbolt fits, the second big decision is the radio. The mechanical retrofit is the same either way — the real difference is what hardware the lock needs to talk to your phone and your smart home system, and what it costs you in extra equipment. For renters, that distinction matters more than the lock's feature list.

Z-Wave: the automation-friendly choice

Z-Wave is one of the most widely adopted wireless protocols for smart-home locks, with 3,000+ certified products backed by Samsung, Google, and Amazon (GetLynx, "Z-Wave vs WiFi vs Zigbee vs Matter"). It runs on a dedicated frequency that doesn't conflict with your 2.4 GHz Wi-Fi, uses 128-bit encryption, and forms a low-power mesh — an important trait for locks that run on AA batteries, since Z-Wave's power draw is low enough to keep battery life practical (GetLynx, "Z-Wave vs WiFi vs Zigbee vs Matter"). The Kwikset Convert Z-Wave kit is a prime example: an interior conversion box marketed explicitly for rentals where the existing deadbolt — and the landlord's key — must stay (CEPRO, "Kwikset Convert Z-Wave Smart Lock Review").

The catch is that a Z-Wave lock needs a Z-Wave hub or bridge as separate hardware, and remote control still depends on your home internet connection (GetLynx, "Z-Wave vs WiFi vs Zigbee vs Matter"). If you already run a SmartThings-style hub, a Z-Wave retrofit slots in cleanly and typically gets the strongest community ratings — Z-Wave retrofits like the August Pro are the most popular retrofit-over-deadbolt class with official integrations (SmartThings Community, "What's the best door lock retrofit over existing dead bolt?"). The Convert is the budget Z-Wave option, though reviewers note its bulky interior box, audible motor, and mixed reviews (CEPRO, "Kwikset Convert Z-Wave Smart Lock Review"; SmartThings Community, "What's the best door lock retrofit over existing dead bolt?").

Bluetooth: the lowest-hardware option

Bluetooth retrofit locks skip the hub requirement: they pair directly with your phone, giving you tap-to-lock control at the door. That's the lightest hardware footprint a renter can get. The trade-off is that remote lock/unlock and reliable home-automation integration depend on a bridge — such as August's Connect bridge — or a hub with Bluetooth bridging (SmartThings Community, "What's the best door lock retrofit over existing dead bolt?"). Bluetooth-class retrofits (Danalock being the reference example) also cost less up front but tend to earn ratings a star or two below the leading Z-Wave kits (SmartThings Community, "What's the best door lock retrofit over existing dead bolt?").

A quick decision guide

• Remote control is essential: plan for a hub either way — Z-Wave hub for Z-Wave kits, a Bluetooth bridge for Bluetooth kits.
• You already have a Z-Wave/SmartThings hub: a Z-Wave retrofit gives you mesh networking, low power draw, and no Wi-Fi interference.
• No hub, phone-at-the-door control is enough: a Bluetooth module keeps things simplest and cheapest.

One catalog note: the Kwikset Convert conversion kit as sold here (KW99140CONX) carries the Zigbee radio. Zigbee shares Z-Wave's low-power mesh profile and AES-128 security but operates at 2.4 GHz, where it can interfere with Wi-Fi; Z-Wave-specific claims apply to the separate Z-Wave variant of the same kit family (e.g., 914ZW500CONV15) (GetLynx, "Z-Wave vs WiFi vs Zigbee vs Matter"; SmartThings Community, "What's the best door lock retrofit over existing dead bolt?").

Practical Setup: Pairing, Batteries, and Real-World Caveats

Related products: Kwikset Convert Smart Lock Conversion Kit with Zigbee

Pairing and Hub Compatibility

Once the kit is mounted, setup depends on your smart home system. The Kwikset Convert requires 4 AA alkaline batteries (not included) and a compatible smart home system — Kwikset lists Xfinity, Cox, Echo Plus, and Samsung SmartThings as working hubs for the Zigbee version [Kwikset Convert sell sheet; Kwikset Support]. There's one pairing quirk to plan for: some Z-Wave systems require the Convert interior to be within 12 in (305 mm) of the controller while adding the lock, so Kwikset's official procedure is to unscrew the interior assembly from the door, complete pairing, then reinstall it [Kwikset Support]. It's trivial, but knowing it in advance means you won't panic when the first pairing attempt fails at full distance. Bluetooth-class modules (the Danalock path) skip the hub for basic use: pairing is just your phone at the door, while remote lock/unlock and reliable automation still depend on a bridge or a hub with Bluetooth bridging [SmartThings Community].

Reading Status and Toggling Behavior

The Convert is status-at-a-glance: an amber LED flash means locked, green means unlocked, and red means the four AA batteries are low [Kwikset Support]. Four interior DIP switches control behavior — Status LED (on by default), Auto-Lock (re-locks 30 seconds after unlock; off by default), Audio (on by default), and Invert [Kwikset Support]. Flip Auto-Lock on if you want the door to re-secure itself after you walk out; left on default, relocking stays manual.

Real-World Caveats

Budget for the physical reality check: the Convert's interior box is large — 9.87 × 3.49 in and 3.99 in deep — and protrudes noticeably from the door, so verify it won't hit a closer arm or frame [CEPRO]. It fits doors 1-3/8" to 1-3/4" thick, ships with three torque-blade adapters to match your existing lock, and is audible in operation with otherwise basic features [CEPRO]. Finally, battery-only power means no hardwiring in a rental: always keep the physical key as a backup and watch the low-battery LED, since an app-only approach can lock a renter out [Gove Locks].

Conclusion: Verdict, Key Takeaways, and Next Steps for Renters

Related products: Kwikset Convert Smart Lock Conversion Kit with Zigbee

The Verdict

For renters, the retrofit conversion kit is the deposit-safe path to a smart lock. It never touches the exterior of the door, so the landlord's original key keeps working for emergency entry — the single biggest reason full-replacement smart locks fail lease review. At move-out, you unscrew the kit, screw the saved thumbturn back on, and the door looks exactly as you left it (Gove Locks, "Smart Locks for Renters"; CEPRO Kwikset Convert review). The trade-off is worth it: a slightly larger interior box, battery maintenance, and the discipline of a key backup.

Key Takeaways

• Start from the right lock. A standard mechanical deadbolt with a working key cylinder and interior thumbturn is the requirement; electronic levers and smart deadbolts are out of scope (Kwikset support).
• Verify before you buy. Confirm your exact lock model on the vendor's published compatibility list — Kwikset maintains a dedicated "What locks are supported by Kwikset Convert?" page (Kwikset support).
• The install is trivial. One screwdriver, under ~10 minutes, 100% reversible (Gove Locks).
• Choose the radio by need. Bluetooth is the smallest-hardware option for phone-at-the-door control (a bridge is needed for remote access); Z-Wave or Zigbee plus a hub buys mesh networking, no Wi-Fi interference, and deeper automation (GetLynx protocol comparison).

Your Next Steps

1. Read the lease and confirm hardware changes are permitted.
2. Measure the door (the Convert fits 1-3/8"–1-3/4" thicknesses) and identify the cylinder type.
3. Decide whether remote control is essential — you'll need a hub or bridge either way.
4. Match the radio to a hub you already own, install, run a reversal test, and label-bag the original hardware (Lockin blog; CEPRO).

Do the five-minute pass/fail audit — no new drill holes, exterior keyway retained, reversible in under 10 minutes, physical key backup exists, renter's insurance unaffected — and if all five check out, the retrofit is a clear win (Gove Locks).

Sources

• govelocks.com
• kwikset.com
• cepro.com
• danalock.com
• cdn.contentspeed.ro
• danalock.com
• kwikset.com
• getlynx.co
• lockin.com

Quick Reference

Not sure which option fits your home? Call our tech support team — we can help you spec the right system before you buy.