7 Best Retro Fit Smart Locks of 2025

The SwitchBot Smart Lock redefines simplicity in home automation with its adhesive-based retrofit design that turns any existing deadbolt into a smart lock in minutes—no tools, no wiring, no permanent changes. What truly sets it apart is its ultra-low barrier to entry: the 3M adhesive mount ensures renters and homeowners alike can upgrade their security without altering door hardware, making it a game-changer for Airbnb hosts and vacation rentals where non-destructive installation is key. With voice control via Siri, Alexa, and Google, plus one-tap remote access through the app, it delivers core smart functionality with zero friction.

In real-world use, the SwitchBot shines in everyday convenience—think unlocking the door for a dog walker while you’re at work or letting in a family member during a rainstorm without getting up from the couch. Its 180-day battery life (at 10 uses/day) means fewer interruptions, and the auto-lock feature based on door closure timing adds a layer of passive security. However, it doesn’t physically throw the deadbolt—it motorizes your existing one—so performance depends heavily on your current lock’s smoothness. On stiff or older mechanisms, you may experience occasional misfires or resistance, especially in colder climates where metal contracts.

Compared to more integrated systems like the Level Lock+, the SwitchBot is less seamless but far more accessible. It’s ideal for users who want smart access without commitment, especially those in rentals or seeking a temporary smart upgrade. While it lacks a keypad or fingerprint sensor, its Apple Watch unlock feature adds a touch of premium convenience at a fraction of the cost. For those prioritizing easy setup and reversibility over all-in-one sophistication, the SwitchBot offers unmatched flexibility—especially when value and simplicity outweigh raw power or full integration.

The TCL D2 Plus isn’t just a smart lock—it’s a security hub on your front door, thanks to its built-in doorbell and real-time video alerts that eliminate the need for a separate doorbell camera. This integration delivers a “see before you unlock” experience that’s rare at this price point, making it a standout for families, hosts, and anyone concerned about package theft or unexpected visitors. Add to that AI-powered fingerprint recognition that unlocks in under 0.3 seconds, even with wet or worn fingers, and you’ve got one of the fastest, most reliable biometric systems in the mid-tier market.

During testing, the IP55 weather resistance proved its worth in heavy rain and sub-zero conditions, with no lag in fingerprint response or Wi-Fi connectivity. The hub-free Wi-Fi is a major win—no extra bridge required—enabling true remote access and instant alerts straight to your phone. Whether you’re unlocking for a guest from the office or checking who rang the bell while on vacation, the TCL Home App delivers smooth, lag-free control. The auto-lock feature with fully customizable delay (5–900 seconds) is perfect for households with kids or pets who might forget to close the door fully, though the lock can occasionally misread a near-closed door as fully shut.

Pitted against the Philips WiFi Smart Lock, the D2 Plus trades a keypad for a camera—but gains far more than it loses. It’s a better fit for tech-savvy families and Airbnb hosts who want all-in-one entry control and monitoring without stacking devices. While slightly pricier than budget models, its combination of speed, security, and built-in visibility makes it a smarter long-term investment. When convenience, speed, and surveillance converge, the D2 Plus outperforms rivals that treat the doorbell as an afterthought.

The Level Lock+ earns its title as the best overall smart lock by blending invisible elegance with military-grade security—a rare feat in a market flooded with bulky, gadgety designs. Its sleek, low-profile body mounts discreetly inside your door, leaving your exterior hardware untouched and your home’s aesthetic intact, while the AAA-rated BHMA certification confirms it meets the highest durability and forced-entry resistance standards in the industry. With Apple Home Key support, you can unlock your door by simply tapping your iPhone or Apple Watch—no app, no code, no fumbling—delivering a luxury-grade entry experience that feels like the future.

Performance-wise, the Lock+ is rock-solid. The 440C stainless steel drive mechanism ensures smooth, consistent operation even after thousands of cycles, and the included Wi-Fi bridge (Level Connect) provides reliable remote access without depending on spotty 2.4GHz signals from your router. In real-world testing, remote lock/unlock commands executed in under 3 seconds, and activity logs updated in real time, crucial for monitoring kids, cleaners, or guests. The auto-lock and key fob features add redundancy, though the lack of a built-in keypad means guests must use the app or a physical key—limiting accessibility for less tech-savvy users.

Compared to the Level Bolt, the Lock+ offers a more integrated experience with Apple Wallet and Home app deep linking, but at a steep price premium. It’s best suited for Apple-centric households who value discreet design, top-tier materials, and seamless automation over budget savings. While the Philips or TCL models offer more features for less, none match the refined build quality and silent sophistication of the Lock+. When security, aesthetics, and Apple ecosystem synergy matter most, the Lock+ justifies its cost through sheer execution.

The Philips WiFi Smart Lock stakes its claim as the best value smart lock with built-in Wi-Fi, delivering a full suite of premium features—including a fingerprint keypad and remote app control—without requiring a separate hub or bridge. This retrofit model clamps over your existing deadbolt, preserving your door’s look and original keys, while adding real-time notifications, activity logging, and auto-locking via door sensor—a rare combo at this price. The included smart keypad is a major differentiator: guests can enter with a code or fingerprint, no app download needed, making it ideal for homes with kids, elderly relatives, or frequent visitors.

In daily use, the built-in Wi-Fi delivers fast, stable remote access, and the app’s real-time logs clearly show who unlocked the door and when—perfect for tracking cleaners or contractors. The auto-lock function works reliably when the door sensor is correctly aligned, but installation demands precision: if the magnet and sensor aren’t perfectly spaced (under 20mm), the lock may fail to engage. On metal door frames, interference can further reduce reliability, requiring careful calibration. Battery life is solid—up to 12 months under moderate use—but the 1.5-pound weight can strain older deadbolts over time.

Against the TCL D2 Plus, the Philips trades a doorbell for a more flexible access system with fingerprint + code + app + key options. It’s better for multi-user homes and rentals where access variety and transparency are critical. While not as sleek as Level’s offerings, it delivers 90% of the functionality at less than half the price. When feature density, compatibility, and guest access are your priorities, the Philips lock offers exceptional bang for the buck.

The Level Bolt is the go-to choice for users who want true remote access without sacrificing their existing door hardware—it replaces only the interior deadbolt mechanism, letting you keep your favorite exterior lock and keys while gaining full smart control. With the included Level Connect Wi-Fi bridge, it offers reliable, long-range connectivity that outperforms hub-free models in homes with weak Wi-Fi coverage, making it ideal for larger houses or buildings with thick walls. The 6-stage stainless steel gearbox ensures robust performance, resisting wear and forced entry far better than plastic-gear competitors.

In real-world testing, the Bolt responded consistently to remote lock/unlock commands from over 100 feet away, thanks to the dedicated bridge. The Level Home app is clean and responsive, offering detailed activity history, user access management, and seamless integration with Apple Home, Alexa, and Google Assistant. Installation is straightforward with just a screwdriver, though it requires removing your existing deadbolt—so it’s less renter-friendly than adhesive models. The lack of a keypad or fingerprint sensor means all smart access flows through the app or voice commands, which can be a bottleneck for guests.

Compared to the Level Lock+, the Bolt offers similar security and remote performance but at a lower cost and without Apple Home Key support. It’s best for homeowners who prioritize remote monitoring and voice control over tap-to-unlock convenience. While the SwitchBot is easier to install, the Bolt delivers far more reliability and peace of mind for long-term use. When remote access stability and hardware retention are non-negotiable, the Bolt outshines Wi-Fi-only rivals that depend on your router’s reach.

The Anona Holo punches well above its weight as the best budget smart lock with Matter support, offering future-proof connectivity with Apple HomeKit, Alexa, and Google Home—no hub needed. This non-destructive retrofit lock installs in minutes with just a screwdriver, clamping over your existing deadbolt to add keyless entry, auto-lock, and anomaly detection without altering your door’s look. Its inertial sensor-based auto-lock detects when the door is closed and locks it automatically, while app alerts warn you if the door is jammed or left open, adding a layer of proactive security rare at this price.

In practice, the 4–6 month battery life (on 4 AA batteries) is efficient, and the low-power travel mode extends it further—perfect for vacation homes. The app allows temporary and one-time passcodes, ideal for dog walkers or Airbnb guests, though the keypad is basic and lacks backlighting, making night entry tricky. Wi-Fi performance is decent but can lag during peak network usage, and the plastic housing feels less premium than metal-bodied rivals. Still, for a sub-$90 lock, it delivers remarkable functionality and ecosystem compatibility.

Stacked against the TCL D1, the Anona Holo offers Matter support and anomaly alerts—a clear edge for smart home enthusiasts—while the TCL wins on fingerprint speed. It’s perfect for budget-conscious users and renters who want secure, modern access without overspending. While it doesn’t have a fingerprint reader or doorbell, its Matter readiness ensures long-term relevance in evolving smart homes. When affordability, Matter compatibility, and retrofit ease are key, the Holo outperforms similarly priced locks that lack forward-looking integration.

The TCL Smart Lock D1 is the best budget fingerprint lock that doesn’t skimp on speed or smarts—unlocking in 0.3 seconds with AI-powered biometrics that adapt to wet, dry, or aging fingers. At under $70, it includes built-in Wi-Fi, remote app control, auto-lock, and voice compatibility with Alexa and Google, making it one of the most feature-packed entry-level smart locks available. Its four-way access (fingerprint, keypad, app, physical key) ensures no one gets locked out, and the lifetime technical support and 12-month warranty add peace of mind often missing in budget models.

Real-world use confirms its reliability: the auto-lock timer (30 seconds to 5 minutes) is highly customizable, perfect for households where doors are often left ajar. The app sends real-time alerts and logs, so you always know who entered and when—great for monitoring kids or service workers. Installation is tool-free and takes under 30 minutes, fitting most standard US doors. However, the plastic build feels less durable than pricier models, and the lack of Apple HomeKit support limits its appeal for iOS-heavy homes.

Compared to the Anona Holo, the D1 trades Matter compatibility for faster, more intuitive biometric access—a fair trade for users who prioritize speed and simplicity over ecosystem flexibility. It’s ideal for first-time smart lock buyers, renters, or secondary doors where cost matters but performance shouldn’t suffer. While it lacks a doorbell or premium materials, it delivers core smart features with remarkable consistency. When fingerprint speed, low cost, and ease of use are the mission, the D1 is the clear budget champion.