What Happens When Your Smart Lock Battery Dies? (Every Model, and How You Get Back In)

By SmartHomeWorkflow Team · Last updated 2026-07-19

Here’s the direct answer, because it’s the thing people actually worry about: a dead smart-lock battery does not lock you out. Every lock in our library is built with a backup way in for exactly this moment. What changes from model to model is which backup, and knowing yours before the battery quits is the whole point of this page. Every fact below traces to a dated, sourced product record.

First: the battery warns you before it dies

A truly dead lock is almost always a warning you ignored. Smart locks watch their own charge and nag you for weeks:

Schlage Encode Plus: app entry at 20%, a critical alert at 8%, plus a flashing red battery icon on the lock itself.
Yale Assure Lock 2 Plus: a notice at 25%, escalating to daily emails and push notifications as it drains.
August Wi-Fi lock: an early low-battery push notification through the app.
eufy FamiLock S3 Max: when the main pack runs low it switches to backup cells for PIN-only entry, so the lock keeps working while you deal with it.

Treat the first alert as the deadline, not the last one. Replace or recharge then and the “dead battery” scenario never arrives.

The three ways back in

Every lock’s backup falls into one of three buckets. Which bucket yours is in is set by whether it keeps a physical keyway.

1. Your existing key (the retrofits). The August Wi-Fi lock, SwitchBot Lock Ultra, and Aqara U200 install over your existing deadbolt and leave the exterior keyway untouched. Your original house key is the dead-battery way in, even if the electronics are completely flat. (The Aqara needs a cylinder with an emergency-key function; measure before buying, per its record.) This is a quiet advantage of retrofit locks and our renters guide leans on it.

2. An included key (the keyed replacements). The Level Lock Pro hides a real keyway behind its ordinary-deadbolt look and ships with two keys; the Schlage Encode Plus includes one. These fully replace the deadbolt but keep a mechanical override.

3. Emergency external power (the key-free locks). The Yale Assure Lock 2 Plus and Schlage Sense Pro have no keyway at all, a deliberate security choice (nothing to pick or bump). Their fallback is power, not a key. Hold a 9V battery to the Yale’s two exterior contact pads, or press a USB-C power bank to the Sense Pro’s jumpstart port. The keypad then wakes up long enough to enter your code. The eufy FamiLock covers all bases: a USB-C emergency port, a physical key, and four built-in AAA cells that take over for PIN-only access.

One myth to retire: the “touch a 9V battery to the terminals” trick is real, but it’s not universal. It works on the Yale here; Schlage’s Encode Plus has no jumpstart of any kind (that 9V feature belongs to Schlage’s older Touch series, not Encode); on the Encode you use the included key. Always check your specific model, which is exactly what the records below are for.

Every lock, shortest battery life to longest

Show only ones that work with:

Product	~Price*	Amazon Alexa	Google Home	Apple Home	SmartThings	Home Assistant	Connection	Hub needed	Works offline	Subscription
Aqara Smart Lock U200✓ fully verified	$169.99	worksAmazon Alexa: works	worksGoogle Home: works	worksApple Home: works	worksSmartThings: works	worksHome Assistant: works	Thread · Matter · Bluetooth	Yes	Partly	—
Aqara Smart Lock U200 — the catch, per ecosystem ~$169.99 at time of research — never treated as a live price ✓ Amazon Alexa: works — Through Matter you get lock, unlock and status. Fingerprint, tap-to-unlock, passcode management and Aqara settings such as auto-lock live in the Aqara Home app. The lock is Thread-only, so you need an Echo or eero that acts as a Thread border router; an older Echo alone will not connect it. ✓ Google Home: works — Google turns off voice unlock for every Matter lock, and turns off remote unlock unless the lock requires a PIN, so 'Hey Google, unlock the door' does not work. You need a Google device with a Thread border router (Nest Hub 2nd gen or Nest Wifi Pro), since the lock is Thread-only. Fingerprint, tap-to-unlock and passcode management stay in the Aqara app. ✓ Apple Home: works — Joins Apple Home through Matter over Thread rather than Apple's older HomeKit route, so you need a home hub with a Thread radio: HomePod, HomePod mini or a Thread-capable Apple TV 4K. Apple Home Key works from a supported iPhone or Apple Watch. Temporary guest codes cannot be set from Apple Home, and fingerprint and tap-to-unlock management stay in the Aqara app. ✓ SmartThings: works — Needs a SmartThings hub with a Thread border router (SmartThings Station, Hub v3, Aeotec, or newer Samsung TVs), because the lock is Thread-only; a hub that only does Matter over Wi-Fi will not connect it. Through Matter you get lock, unlock and status; fingerprint, tap-to-unlock and Aqara settings stay in the Aqara app. ✓ Home Assistant: works — Works through Home Assistant's official Matter support, including managing PIN codes, but you need Home Assistant's Matter add-on plus a Thread border router on the network because the lock is Thread-only. Fingerprint and tap-to-unlock enrollment and Aqara-specific settings still need the Aqara app, and community reports say managing lock codes through Matter can be unreliable on this model. Connection: Thread · Matter · Bluetooth · Hub for full use: Yes (Needs a Thread border router in whichever ecosystem you choose. The lock has no Wi-Fi radio; everything runs over Thread. A HomePod, HomePod mini or Apple TV 4K, a Thread-capable Echo or eero, a Nest Hub (2nd gen) or Nest Wifi Pro, or a Thread-capable SmartThings hub all qualify.) · Works offline: Partly — some of it keeps working without the internet and some of it does not Full sourced profile for Aqara Smart Lock U200 →
August WiFi Smart Lock (4th gen)✓ fully verified	$199.99	worksAmazon Alexa: works	worksGoogle Home: works	worksApple Home: works	worksSmartThings: works	worksHome Assistant: works	Wi-Fi · Bluetooth	Yes	Partly	—
August WiFi Smart Lock (4th gen) — the catch, per ecosystem ~$199.99 at time of research — never treated as a live price ✓ Amazon Alexa: works — Cloud-to-cloud via the August Alexa skill using the lock's built-in WiFi — lock and status by voice anytime, but voice UNLOCK requires a 4–12 digit PIN configured during skill account linking; no PIN set, no voice unlock. ✓ Google Home: works — Cloud-to-cloud Works-with-Google-Home linking using the lock's built-in WiFi. Voice unlock works but Google requires a spoken security PIN for any voice unlock — a Google platform rule for locks, not stated on August's page. ✓ Apple Home: works — HomeKit is genuinely native on the 4th gen (WiFi/Bluetooth in the lock, no bridge). Remote Siri/Home-app control away from home needs an Apple home hub (HomePod or Apple TV). No Matter support — August's own compatibility pages list no Matter or Thread anywhere (re-checked 2026-08-07, still absent). ✓ SmartThings: works — Official cloud-to-cloud linked service — SmartThings talks to August's cloud, so it needs the lock's WiFi online and there is no local execution; no SmartThings hub required. ✓ Home Assistant: works — Official integration in Home Assistant core (since 0.64, IoT class Cloud Push) covering lock/unlock, DoorSense door state, battery, and who-operated attribution — but entirely cloud-dependent on the August/Yale cloud (no local API), some data updates slowly because August offers no push API for it, and HA's docs flag Gen-4 battery reporting as frequently inaccurate. Connection: Wi-Fi · Bluetooth · Hub for full use: Yes (No bridge, and that is the 4th generation's whole point — the radio moved into the lock. August states it plainly: 'the August Wi-Fi Smart Lock requires no additional bridge to connect. Wi-Fi capability is built right into the smart lock.' Home Assistant's own documentation agrees from the other side, listing the Gen 4 among the devices that do not require a Connect Bridge or Doorbell. Worth knowing if you are comparing against the older Smart Lock + Connect, which does need one. The lock's Wi-Fi is unusually flexible for this category: 802.11 b/g/n on 2.4GHz OR 5GHz, where most smart locks are 2.4GHz-only.) · Works offline: Partly — some of it keeps working without the internet and some of it does not Full sourced profile for August WiFi Smart Lock (4th gen) →
ULTRALOQ Bolt Fingerprint (Apple Home + Wi-Fi)	$199.99	worksAmazon Alexa: works	worksGoogle Home: works	worksApple Home: works	worksSmartThings: works	inconclusiveHome Assistant: we researched this and the evidence does not settle it — the profile has the sources	Wi-Fi · Bluetooth	No	?	—
ULTRALOQ Bolt Fingerprint (Apple Home + Wi-Fi) — the catch, per ecosystem ~$199.99 ultraloq.com listed the Bolt Fingerprint at $199.99 on 2026-08-14, read from the storefront's structured product endpoint; both Apple Home + Wi-Fi variants (satin nickel and black) carry that price with no compare-at figure, identical to the Matter-over-Thread variant. Price at time of research. ✓ Amazon Alexa: works — ULTRALOQ lists this variant as working with 'Apple Home, Amazon Alexa, Google Home, SmartThings, IFTTT'. The route is not stated — this version is not the Matter one, so the connection is ULTRALOQ's own Wi-Fi service rather than Matter, and the level rests on the manufacturer's word alone. Amazon publishes no per-model entry to check it against. ✓ Google Home: works — Named in ULTRALOQ's list for this variant. As with Alexa, the mechanism is unstated and non-Matter, so the claim rests on the manufacturer's word; no Google-side per-model listing was found. ✓ Apple Home: works — This is the version ULTRALOQ actually names Apple Home for, and it is the reason to choose it: the variant is literally titled 'Apple Home + WiFi + Bluetooth'. ⚠ ULTRALOQ does not say whether the pairing is HomeKit or Matter, and this variant is not the one covered by the Matter certificate — so 'Apple Home' here is the vendor's claim, not a certified route. As with any Apple Home accessory, remote control away from the house needs an Apple home hub: ULTRALOQ's own FAQ says 'you will need to set up an iPad, HomePod, or Apple TV as your remote control hub', which sits awkwardly beside the variant selector's 'no hub required' line. Both are true of different things — the lock needs no bridge for Wi-Fi; Apple needs a home hub for remote access. ✓ SmartThings: works — Named in ULTRALOQ's platform list for this variant. Mechanism unstated and non-Matter; no SmartThings-side listing for this model was found, so the claim rests on ULTRALOQ's word. ? Home Assistant: inconclusive — Home Assistant appears nowhere on ULTRALOQ's product page, and no ULTRALOQ statement of support or non-support was found. Unlike the Matter-over-Thread version of this same lock — which HA can commission through its official Matter integration — this variant has no certified local route to point HA at. Recorded unknown rather than none because the vendor says nothing either way. Connection: Wi-Fi · Bluetooth · Hub for full use: No — verified that none is needed · Works offline: Not checked — we have not established whether this keeps working without the internet Full sourced profile for ULTRALOQ Bolt Fingerprint (Apple Home + Wi-Fi) →
ULTRALOQ Bolt Fingerprint (Matter over Thread)✓ fully verified	$199.99	worksAmazon Alexa: works	worksGoogle Home: works	worksApple Home: works	worksSmartThings: works	worksHome Assistant: works	Thread · Matter · Bluetooth	Yes	Partly	—
ULTRALOQ Bolt Fingerprint (Matter over Thread) — the catch, per ecosystem ~$199.99 ultraloq.com listed the Bolt Fingerprint at $199.99 on 2026-08-14, read from the storefront's structured product endpoint; the Matter-over-Thread variant (SKU BOLT-F-MATTER) carries the same price as the Wi-Fi/Apple Home variants and no compare-at figure. Price at time of research. ✓ Amazon Alexa: works — ULTRALOQ lists this variant as working with 'Matter-compatible platforms including Apple Home, Alexa, Google Home, and Samsung SmartThings'. Everything runs over Matter-over-Thread, so the Echo in question must be a Thread border router — a plain Echo Dot gets you nothing. Alexa's standard voice-unlock code gate applies. ✓ Google Home: works — Named in ULTRALOQ's Matter platform list, over Thread only — needs a Google Thread border router (Nest Hub 2nd gen, Nest Hub Max, Nest Wifi Pro). Google disables voice unlock for Matter locks and restricts remote unlock, so expect lock and status to be the reliable operations. ✓ Apple Home: works — Reached through Matter rather than a legacy HomeKit pairing on this variant, so it needs a Thread-capable Apple home hub (HomePod, HomePod mini, or Apple TV 4K with Thread). ⚠ Do not read Apple Home Key into this: ULTRALOQ sells Home Key on its Bolt NFC line, and nothing on the Bolt Fingerprint page claims it for this model. ✓ SmartThings: works — Named by ULTRALOQ ('Samsung SmartThings') and corroborated by the Matter certificate. Requires a SmartThings hub that is a Thread border router; a hubless SmartThings app cannot commission a Thread-only device. ✓ Home Assistant: works — Home Assistant is not mentioned anywhere on ULTRALOQ's page — this level rests on the Matter certificate, not on the vendor's word. HA's official Matter integration commissions certified locks over Thread (with a Matter server and a border router such as HA's own OpenThread Border Router add-on) and exposes lock, unlock, state and PIN-credential management. Fingerprint enrolment and user management stay in the U-tec app. Connection: Thread · Matter · Bluetooth · Hub for full use: Yes (Needs a Thread border router — ULTRALOQ states it plainly for this variant ('Requires a Matter Over Thread hub controller (Thread border router)'), and the Matter certificate lists Thread as the ONLY transport. There is no Wi-Fi radio in this version to fall back on.) · Works offline: Partly — some of it keeps working without the internet and some of it does not Full sourced profile for ULTRALOQ Bolt Fingerprint (Matter over Thread) →
Aqara Smart Lock U400	$269.99	inconclusiveAmazon Alexa: we researched this and the evidence does not settle it — the profile has the sources	inconclusiveGoogle Home: we researched this and the evidence does not settle it — the profile has the sources	worksApple Home: works	inconclusiveSmartThings: we researched this and the evidence does not settle it — the profile has the sources	inconclusiveHome Assistant: we researched this and the evidence does not settle it — the profile has the sources	Thread · Matter · Bluetooth +1	Yes	?	—
Aqara Smart Lock U400 — the catch, per ecosystem ~$269.99 at time of research — $269.99 read from Aqara's own storefront structured data (SKUs DTC-US-EN-U400-BLACK and DTC-US-EN-U400-SLIVER, both in stock at the same price) rather than the rendered page, per this vendor's standing method rule. ⚠ Budget beyond the lock if UWB hands-free unlocking is why you want it: Aqara requires 'a Thread-enabled Apple Home hub' for that feature, which is a HomePod or Apple TV you may not already own. Never treated as a live price. ? Amazon Alexa: inconclusive — Not established for this model. Aqara's description names Apple Home explicitly and then generalises — 'Aqara and other Matter-compatible platforms through the Aqara app' — without naming Alexa. Alexa is a Matter controller, so the lock is very likely reachable there, but 'likely' is not evidence and this catalogue does not publish protocol theory as a compatibility claim. Recorded as unknown rather than inferred. ? Google Home: inconclusive — Same position as Alexa: not named in Aqara's own description for this lock, and not inferred from the fact that it speaks Matter. An honest unknown. ✓ Apple Home: works — ⚠ THE DEEPEST APPLE STORY IN THIS CATALOGUE'S LOCK SHELF, AND THE ONE WITH THE MOST PREREQUISITES — read both halves. Aqara names Apple Home support with specific minimum versions, 'iOS 18.5+, watchOS 11.5+', and the headline feature is UWB hands-free unlocking: the door opens as you approach with your phone or watch, no tapping. But that feature is not in the box. Aqara states it needs 'a Thread-enabled Apple Home hub', and tap-to-unlock needs 'an Apple Thread-enabled Matter controller' — a HomePod or a Wi-Fi + Ethernet Apple TV 4K, bought separately; the Wi-Fi-only Apple TV 4K has no Thread radio. Without one you have a capable keypad-and-fingerprint lock and none of the hands-free behaviour it is sold on. ? SmartThings: inconclusive — Not established — Aqara's description for this lock names Apple Home and 'other Matter-compatible platforms' generically without naming SmartThings, and no per-model statement was found in either direction. ? Home Assistant: inconclusive — Not established for this model, and deliberately not borrowed from siblings: Aqara names Home Assistant explicitly on its G410 doorbell and G350 camera pages, and does NOT name it in this lock's description. The same vendor's platform lists demonstrably differ per product, so the omission stays an unknown rather than becoming either an inherited yes or an evidenced no. Connection: Thread · Matter · Bluetooth · NFC · Hub for full use: Yes (Not for the lock's basic operation — fingerprint, passcode, NFC card and physical key all work at the door with nothing else in the house. But two of the features Aqara sells it on DO require hardware you buy separately, and Aqara names them precisely: UWB hands-free unlocking needs 'a Thread-enabled Apple Home hub', and tap-to-unlock needs 'an Apple Thread-enabled Matter controller'. In practice that means a HomePod, a HomePod mini or a Thread-capable Apple TV 4K; the Wi-Fi-only Apple TV 4K has no Thread radio and does not qualify. Anything Thread-based also needs a Thread border router to reach your phone remotely, which is the same box. If the hands-free trick is the reason you are buying this lock, price that hub alongside it.) · Works offline: Not checked — we have not established whether this keeps working without the internet Full sourced profile for Aqara Smart Lock U400 →
SwitchBot Lock Ultra Vision Pro Combo✓ fully verified	$279.99	worksAmazon Alexa: works	worksGoogle Home: works	partialApple Home: partial support — see the catch	partialSmartThings: partial support — see the catch	worksHome Assistant: works	Matter · Wi-Fi · Bluetooth	Yes	?	—
SwitchBot Lock Ultra Vision Pro Combo — the catch, per ecosystem ~$279.99 $279.99 for the full combo (Lock Ultra + Hub Mini Matter + Keypad Vision Pro), read from SwitchBot's own store on 2026-08-08 — price at time of research, never a live price. The lock alone is $139.99, and SwitchBot sells five other configurations in between ✓ Amazon Alexa: works — Via the SwitchBot Smart skill, which needs a SwitchBot hub online — included here. Voice unlock requires a PIN code set in the Alexa app. ✓ Google Home: works — Cloud account linking to Google Home, which needs a SwitchBot hub online — included here. Voice unlock requires a PIN code set in the SwitchBot app. ◐ Apple Home: partial — Lock/unlock and Siri via Matter, and the Matter-capable hub this needs — a Hub Mini Matter — is included in this combo, so the path works out of the box. Worth knowing if you shop the cheaper configurations: the base Hub Mini does NOT qualify. No Apple Home Key — SwitchBot states its Lock products do not support it. Face, palm and fingerprint stay in the SwitchBot app. ◐ SmartThings: partial — Via Matter as a bridged secondary device, and the Matter-capable hub required for it ships in this combo. The base Hub Mini does not qualify, so a cheaper SwitchBot bundle may not reach SmartThings at all. Biometrics stay in the SwitchBot app. ✓ Home Assistant: works — Two official HA core paths: the Bluetooth-local switchbot integration (no hub, no cloud — Lock Ultra explicitly listed: lock/unlock, door state, auto-lock, calibration, battery) and the switchbot_cloud integration via a hub. Keypad biometrics are not exposed to HA. Connection: Matter · Wi-Fi · Bluetooth · Hub for full use: Yes (Included in this combo — the Hub Mini Matter that unlocks Wi-Fi remote access, Matter, Apple Home and SmartThings ships in the box) · Works offline: Not checked — we have not established whether this keeps working without the internet Full sourced profile for SwitchBot Lock Ultra Vision Pro Combo →
Kwikset Halo Select Plus Touchscreen Smart Lock✓ fully verified	$309	worksAmazon Alexa: works	worksGoogle Home: works	worksApple Home: works	worksSmartThings: works	worksHome Assistant: works	Thread · Matter · Wi-Fi	No	Partly	—
Kwikset Halo Select Plus Touchscreen Smart Lock — the catch, per ecosystem ~$309 Kwikset's own product page listed the Satin Nickel Halo Select Plus at $309.00 on 2026-08-14. Price at time of research, not a live price; Kwikset shows no compare-at figure on this listing. ✓ Amazon Alexa: works — Kwikset states 'Works with Amazon Alexa, Apple Home and Google Home. Control your lock with your voice, create helpful automations that secure your home and manage all your smart devices in one app.' The lock is Matter 1.3 certified with Wi-Fi AND Thread transports (CSA certificate CSA25931MAT47235-24), so an Echo can reach it over either — unlike the Thread-only Matter locks on this shelf, which need a Thread border router before they work at all. Transport is left unknown because which radio a given Alexa setup commissions is not stated by either party. Alexa's standard voice-unlock code gate applies. ✓ Google Home: works — Named by Kwikset alongside Alexa and Apple Home, and reachable over Matter (certificate above). Google restricts remote unlock for Matter locks and disables voice unlock; expect lock and status to behave normally and unlock to be the restricted operation. Neither party publishes a per-model capability list. ✓ Apple Home: works — The reason to buy the Plus over the plain Select: 'With NFC technology and Apple home keys, simply tap to unlock Halo Select Plus using your iPhone or Apple Watch for easy and secure access to your home.' Home Key is provisioned through Apple Home, and Kwikset names Apple Home in its works-with statement. As with every Apple Home accessory, remote access away from the house needs an Apple home hub (HomePod or Apple TV); Kwikset does not say so on this page, and it is Apple's requirement rather than Kwikset's. ✓ SmartThings: works — SmartThings is NOT named on Kwikset's page — the level rests on the Matter certificate rather than on the manufacturer's marketing. SmartThings is a Matter controller, and this lock is Matter 1.3 certified over Wi-Fi and Thread, so a current SmartThings setup can commission it and drive the standard Door Lock cluster. Anything Kwikset-specific — SmartKey, geofence auto-unlock, code scheduling beyond Matter's own model — stays in the Kwikset app. ✓ Home Assistant: works — Home Assistant is not named by Kwikset either; this too rests on the Matter certificate. HA's official Matter integration (with a Matter server) commissions certified locks and exposes lock/unlock, state and PIN-credential management. Because this lock carries a Wi-Fi Matter transport as well as Thread, an HA household does not need a Thread border router to use it — which is unusual on this shelf and is the practical reason to prefer it over Thread-only Matter locks. Connection: Thread · Matter · Wi-Fi · Hub for full use: No — verified that none is needed · Works offline: Partly — some of it keeps working without the internet and some of it does not Full sourced profile for Kwikset Halo Select Plus Touchscreen Smart Lock →
Yale Assure Lock 2 Plus✓ fully verified	$309.99	worksAmazon Alexa: works	worksGoogle Home: works	worksApple Home: works	worksSmartThings: works	partialHome Assistant: partial support — see the catch	Wi-Fi · Bluetooth · NFC	No	?	—
Yale Assure Lock 2 Plus — the catch, per ecosystem ~$309.99 $309.99 for the Wi-Fi configuration this record describes (YRD450-N-WF1, 'Assure Lock 2 Plus with Wi-Fi and Apple Home Keys'), read from Yale's own store structured offer data on 2026-08-08. ⚠ THE NAME COVERS THREE CONFIGURATIONS AT TWO PRICES: the Bluetooth-only 'with Apple Home Keys' (YRD450-N-BLE) is $219.99, and a 'Wi-Fi Connect for Vacation Rental Hosts' variant (YRD450-N-CB1) is also $309.99. A bare price under this product name means nothing without the configuration attached. Never treated as a live price. ✓ Amazon Alexa: works — Needs the built-in Wi-Fi (WF1) model ✓ Google Home: works — Needs the built-in Wi-Fi (WF1) model ✓ Apple Home: works — Apple Home Key via NFC tap; HomeKit over Wi-Fi/Bluetooth — not Thread or Matter ✓ SmartThings: works — Needs the built-in Wi-Fi (WF1) model ◐ Home Assistant: partial — Officially supported in HA core two ways, both with real setup caveats: the August/Yale-Access cloud integration lists the Assure Lock 2 (the lock must be online — built-in Wi-Fi WF1 model or a Connect bridge), and the local Yale Access Bluetooth (yalexs_ble) integration lists the YRD450 but requires extracting the Yale Access offline key. HA's docs name the base YRD450/Assure Lock 2 family, not the Home-Key '-N Plus' variant specifically. Connection: Wi-Fi · Bluetooth · NFC · Hub for full use: No — verified that none is needed · Works offline: Not checked — we have not established whether this keeps working without the internet Full sourced profile for Yale Assure Lock 2 Plus →
Schlage Encode Plus✓ fully verified	$329	worksAmazon Alexa: works	worksGoogle Home: works	worksApple Home: works	doesn't workSmartThings: verified: does not work	worksHome Assistant: works	Thread · Wi-Fi · Bluetooth	?	?	—
Schlage Encode Plus — the catch, per ecosystem ~$329 $329 MSRP on schlage.com on 2026-08-10. The 2026-08-08 note that Schlage published no price anywhere on its own site is no longer true: the encode-plus page now carries a product-comparison widget stating '$329 MSRP' against the Schlage Encode Plus Smart WiFi Deadbolt by name. At time of research — never treated as a live price. ✓ Amazon Alexa: works — Built-in WiFi (no hub) but requires the Schlage Home app plus enabling the Alexa skill — a cloud-linked skill, not a hubless native pairing. ✓ Google Home: works — Built-in WiFi but requires the Schlage Home app and linking the Schlage service in Google Home — a cloud-linked service, not direct native pairing. ✓ Apple Home: works — Native HomeKit over Thread with Apple Home Key. Remote control, automations, and sharing Tap to Unlock require a HomePod or Apple TV set up as an Apple home hub (a HomePod or the Wi-Fi + Ethernet Apple TV 4K also provides the Thread border router; the Wi-Fi-only Apple TV 4K does not). Not a Matter device — Schlage's KB states the Encode Plus is not Matter-enabled. ✗ SmartThings: doesn't work — Schlage's own support KB states the Encode Series (including Encode Plus) is not SmartThings-compatible — the lock is WiFi-only with no Z-Wave and no Matter, so no SmartThings path exists; Schlage points SmartThings households to the Z-Wave Schlage Connect instead. ✓ Home Assistant: works — Official Schlage integration in Home Assistant core (since 2023.9), cloud-polling via Schlage's cloud API (~30-second state refresh, internet required) — the Encode Plus is an explicitly tested device with lock control, PIN-code management, auto-lock, and battery sensors. The HomeKit-controller-over-Thread route remains an optional local alternative. Connection: Thread · Wi-Fi · Bluetooth · Hub for full use: Not checked — we have not established whether this needs a hub · Works offline: Not checked — we have not established whether this keeps working without the internet Full sourced profile for Schlage Encode Plus →
Level Lock Pro✓ fully verified	$349	worksAmazon Alexa: works	worksGoogle Home: works	worksApple Home: works	worksSmartThings: works	worksHome Assistant: works	Thread · Matter · Bluetooth	Yes	Partly	—
Level Lock Pro — the catch, per ecosystem ~$349 at time of research — never treated as a live price. Re-verified unchanged 2026-08-08 at Level's own store. ✓ Amazon Alexa: works — Matter-over-Thread needs an Echo that is a Thread border router — Level names Echo (4th gen), Echo Hub, Echo Plus (2nd gen), Echo Show 8/10 (3rd gen), Echo Studio, and eero 6/6+/Pro/Max models. The Level Connect cloud bridge exists as a non-Matter alternative, but it is a 1:1 bridge and cloud-dependent. ✓ Google Home: works — Matter-over-Thread needs a Google hub that is a Thread border router — Level names Nest Hub (2nd gen), Nest Hub Max, Nest Wifi, Nest Wifi Pro, and Google TV Streamer 4K. Level Connect cloud path is the non-Matter alternative (1:1, cloud-dependent). ✓ Apple Home: works — Apple Home Key needs iPhone XS+ on iOS 17.1+ or Apple Watch Series 4+ on watchOS 10.1+; remote access and automations need an Apple Home hub (HomePod mini, HomePod 2nd gen, or Apple TV 4K 3rd gen Wi-Fi+Ethernet). The lock is also Matter-certified, so a Matter path into Apple Home exists alongside the Home Key pairing. ✓ SmartThings: works — Needs SmartThings hardware that is a Thread border router — Level names the Aeotec Smart Home Hub, SmartThings Station, Hub Dongle, Hub v3, plus select 2023 Samsung TVs, monitors, soundbars, and appliances. ✓ Home Assistant: works — Local via Home Assistant's official Matter integration (Level has an official HA brand page since 2025.10); needs a Thread border router in the HA setup, and commissioning pairs over the phone's Bluetooth — community threads report initial Level-lock pairing failures. Connection: Thread · Matter · Bluetooth · Hub for full use: Yes (Thread border router (HomePod, the Wi-Fi + Ethernet Apple TV 4K, newer Echo/Nest hubs) for Matter/remote — or the $79 Level Connect WiFi bridge (1 bridge per lock)) · Works offline: Partly — some of it keeps working without the internet and some of it does not Full sourced profile for Level Lock Pro →
Lockly Visage Zeno Series Facial Recognition Deadbolt	$349	worksAmazon Alexa: works	worksGoogle Home: works	partialApple Home: partial support — see the catch	doesn't workSmartThings: verified: does not work	inconclusiveHome Assistant: we researched this and the evidence does not settle it — the profile has the sources	Wi-Fi · Bluetooth	No	?	Optional*
Lockly Visage Zeno Series Facial Recognition Deadbolt — the catch, per ecosystem ~$349 Lockly listed the Visage Zeno Series deadbolt at $349.00 on 2026-08-14, read from its own storefront data; both finishes carry that price, and no crossed-out original price is recorded even though the page presents it as a 'Sale price'. Price at the time we researched it. ✓ Amazon Alexa: works — Lockly names Alexa on the product page, and on this lock it works over the built-in Wi-Fi rather than through Matter — Lockly's hub page states the fallback explicitly: 'Devices not compatible with Matter, but that support Alexa or Hey Google, can still use voice control by pairing with a hub', and this lock needs no hub because its Wi-Fi is built in. Vendor's word alone; Amazon publishes no per-model entry. ✓ Google Home: works — Named by Lockly ('Hey Google') on the same non-Matter, Wi-Fi-based route as Alexa. The Zeno Series page footnotes voice support as requiring the Wi-Fi connection. Vendor's word alone. ◐ Apple Home: partial — Lockly states 'Apple Home Key compatible — Unlock with iPhone or Apple Watch' and lists Siri among the voice options, so tap-to-unlock is claimed. What is NOT established is how much of Apple Home you get beyond it: this lock is absent from Lockly's own Matter-compatible device list, Lockly does not describe a HomeKit pairing, and no Apple-side listing for the model was found. Recorded partial because the credential is claimed and the wider platform integration is not evidenced — an Apple household should treat Home Key as the feature it is buying, not full Home-app parity. ✗ SmartThings: doesn't work — This is an evidenced no, not a silence. Lockly states the rule — 'Only Matter-compatible Lockly devices support Siri voice control and automation with Apple Home, Amazon Alexa, Google Home, and Samsung SmartThings via Matter integration' — and publishes the membership list at lockly.com/pages/matter-compatible-devices, which names the Model S, Secure Plus/Pro latches and deadbolts, Secure Lux Mortise, Flex Touch and Access Touch models, the Compact models and the Guard series, and does NOT include the Visage Zeno. Lockly's only stated route to SmartThings is Matter, and this lock is not on the Matter list. ? Home Assistant: inconclusive — Lockly names no Home Assistant support and states no non-support either. There is no Matter certification to give Home Assistant a standard route in — this lock is absent from Lockly's own Matter list — and no way to control it on your own network is documented. We record this as unknown rather than as a no because the maker says nothing in either direction, but a Home Assistant household should assume nothing here works until there is evidence. Connection: Wi-Fi · Bluetooth · Hub for full use: No — verified that none is needed · Works offline: Not checked — we have not established whether this keeps working without the internet Full sourced profile for Lockly Visage Zeno Series Facial Recognition Deadbolt →
Schlage Sense Pro✓ fully verified	$399	worksAmazon Alexa: works	worksGoogle Home: works	worksApple Home: works	worksSmartThings: works	worksHome Assistant: works	Thread · Matter · Wi-Fi +1	Yes	?	—
Schlage Sense Pro — the catch, per ecosystem ~$399 at time of research — never treated as a live price. Re-verified unchanged 2026-08-08 against Schlage's own launch announcement. ✓ Amazon Alexa: works — Matter-over-Thread only (the CSA cert lists Thread as the sole Matter transport) — requires an Echo or eero that is a Thread border router; a plain Echo Dot gets no integration at all. Lock/unlock/status via Matter's Door Lock cluster, with Alexa's standard voice-unlock code gate. UWB hands-free, entrance modes, and access-code scheduling stay in the Apple Wallet/Schlage Home apps. ✓ Google Home: works — Matter-over-Thread only — requires a Google Thread border router (Nest Hub 2nd gen, Nest Hub Max, Nest Wifi Pro). Google disables voice unlock for Matter locks and disables remote unlock unless the lock mandates a PIN — expect lock/status to work, with unlock restricted (whether the Sense Pro mandates a PIN over Matter is unverified). UWB hands-free is Apple-only today; Google Wallet Aliro keys are announced, not shipping. ✓ Apple Home: works — The strongest ecosystem: Apple Home Key + UWB hands-free unlock are shipping and Apple-exclusive today — needs iPhone 11+/Apple Watch Series 6+ AND a Thread-enabled home hub (Apple TV 4K 2nd/3rd gen Wi-Fi+Ethernet, HomePod 2nd gen, HomePod mini). Apple Home control rides Matter, not a legacy HomeKit pairing; hands-free is set up in Apple Home but the three UWB entrance modes are configured in the Schlage Home app. ✓ SmartThings: works — Matter-over-Thread only — requires a SmartThings hub that is a Thread border router; hubless SmartThings app users cannot connect this lock. Lock/unlock/status/codes per Matter's Door Lock cluster. UWB hands-free is not available to SmartThings users today — Samsung Wallet Aliro keys are announced pending certification, and entrance-mode config stays in the Schlage Home app. ✓ Home Assistant: works — Needs the HA Matter integration (Matter server) plus a Thread border router (e.g., HA's OpenThread Border Router add-on or a Nest hub). HA's Matter lock support is unusually deep — set/clear lock users and PIN credentials via documented actions — but UWB hands-free, entrance modes, and Schlage-specific settings stay in the Schlage/Apple apps. Connection: Thread · Matter · Wi-Fi · UWB · Hub for full use: Yes (Needs a Thread border router in whichever ecosystem you choose — HomePod/Apple TV 4K, a Thread-capable Echo or eero, Nest Hub (2nd gen)/Nest Wifi Pro, or a Thread-capable SmartThings hub. Its WiFi radio serves only the Schlage Home app; Matter runs over Thread alone.) · Works offline: Not checked — we have not established whether this keeps working without the internet Full sourced profile for Schlage Sense Pro →
eufy FamiLock S3 Max✓ fully verified	$399.99	worksAmazon Alexa: works	worksGoogle Home: works	partialApple Home: partial support — see the catch	partialSmartThings: partial support — see the catch	partialHome Assistant: partial support — see the catch	Matter · Wi-Fi	No	?	—
eufy FamiLock S3 Max — the catch, per ecosystem ~$399.99 at time of research, eufy's own product page structured data — $399.99 against SKU E85V0JY1, availability InStock. Never treated as a live price. ⚠ CORRECTED from $330, a $69.99 UNDERSTATEMENT, which is the direction that costs a reader more: someone budgeting from our page would have arrived $70 short. Read from the product's own schema.org Product block rather than the rendered page, because that page also prints $349.99, $299.99 and $599.98 for other eufy locks and bundles in its cross-sell. ✓ Amazon Alexa: works — Lock control + doorbell announcements ✓ Google Home: works — no catch on record ◐ Apple Home: partial — Lock control via Matter over Wi-Fi (eufy's page names Apple Home) — but video doesn't travel over Matter, so the doorbell-cam half stays in the eufy app; Apple Home sees just a lock. ◐ SmartThings: partial — eufy's product page states it integrates with SmartThings via Matter over Wi-Fi — but Matter carries lock control only; eufy's Matter FAQ notes camera streams are not supported over Matter, so the lock's video features stay in the eufy app. ◐ Home Assistant: partial — No official eufy integration covers this lock (HA core's EufyHome integration is lights/switches only) — but an official standards path exists: pair via Matter over Wi-Fi with HA's core Matter integration for lock control. Video and doorbell features don't travel over Matter and stay in the eufy app; the unofficial eufy_security community integration remains the only route to those. Connection: Matter · Wi-Fi · Hub for full use: No — verified that none is needed · Works offline: Not checked — we have not established whether this keeps working without the internet Full sourced profile for eufy FamiLock S3 Max →
No products in this category work with that ecosystem in our records yet. A Setup Check can research options outside our library.

Sorted by price, low to high — an objective order, not a ranking or a verdict. Tap any row’s ＋ (or a phone card) to read every catch. ✓ works · ◐ partial · ✗ doesn’t work (verified) · ? not checked yet · ? inconclusive — we researched it and the evidence doesn’t settle it. In the decision columns, ? means the same thing — we have not established it, which is never the same as “no.” *Prices at time of research — never live prices. Data last verified 2026-08-20; every fact links to its sourced profile.

Which of these works with your home?

Check smart locks against your setup →

Don’t see the exact model you own? Two options, and they’re different:tell us and we’ll add it to the research queue (free), or get aSetup Check — a personalized, human-checked report that researches your whole list, including products we haven’t profiled yet.

Read that table for the ecosystem and subscription columns. Here it is re-cut for the battery question specifically, from the same records.

Lock	Battery	Rated life	Dead-battery way in
August Wi-Fi lock	2× CR123A	~3 months	Your existing exterior key (retrofit)
eufy FamiLock S3 Max	15,000mAh rechargeable + 4× AAA	~5 months	USB-C emergency port · physical key · AAA cells (PIN-only)
Aqara U200	Li-ion pack (or 4× AA)	~6 months	Your existing exterior key (retained cylinder)
Schlage Encode Plus	4× AA	~6 months	Included physical key (no jumpstart)
Schlage Sense Pro	4× AA	~6 months	USB-C jumpstart port (key-free)
Level Lock Pro	1× CR2 lithium	~9–12 months	Included physical key (hidden keyway)
SwitchBot Lock Ultra	Rechargeable pack	~12 months	Existing key · CR123A backup · Type-C emergency power
Yale Assure Lock 2 Plus	4× AA	~18 months	Exterior 9V terminal (key-free)

A dead lock battery isn’t a dead phone

Two “dead battery” questions get tangled together, so keep them apart.

Your lock’s battery is what this page is about: the lock stops responding until you use its backup path above.
Your phone’s battery is a different failure. If you use Apple Home Key, a dead iPhone still taps for a few hours in Power Reserve, and the lock’s own keypad or key is always there as a fallback. That question is covered in the Home Key guide.

And note what doesn’t go down with the lock’s battery: on locally-controlled models, the keypad and biometrics keep working right up until the cells quit. The most cloud-tied lock here is the August: a Wi-Fi or cloud outage degrades its remote control, but the batteries and your key are independent of that.

How to never get caught out

Stock the right chemistry. AA cells are everywhere, but the Level Lock Pro (CR2) and August (CR123A) use less-common cells, so keep a spare set in a drawer, not a mental note.
Lean on the long-lived ones if maintenance annoys you. The Yale Assure Lock 2 Plus (~18 months) asks the least of you; the Level Lock Pro and SwitchBot Lock Ultra are close behind near a year.
Rechargeable packs need a routine. The Aqara U200, eufy FamiLock, and SwitchBot never need new cells, but a pack at zero still needs its backup, so build a recharge habit around the low-battery alert.
Key-free? Keep the tool in the car. If your lock is the Yale or the Sense Pro, a spare 9V battery or a small USB-C power bank in the glovebox is your “key.”

The battery question rarely decides a purchase on its own, but it’s a real part of living with a smart lock, so it’s a column in our full lock directory and a fact on every profile. To match a lock to the rest of your setup, run it through the compatibility checker, or start from the quiz if you’re still choosing an ecosystem.

Frequently asked questions

If my smart lock battery dies, am I locked out?

No. Every smart lock is designed so a dead battery can't strand you — but the way back in differs by model. Retrofit locks (August, SwitchBot, Aqara) keep your existing physical key working. Keyed deadbolts (Level Lock Pro, Schlage Encode Plus) include a real key. And key-free locks (Yale Assure Lock 2 Plus, Schlage Sense Pro) use an emergency power contact — a 9V battery or a USB-C power bank held to the lock — to wake it up long enough to enter your code.

Will the lock warn me before the battery dies?

Yes, usually with weeks of notice. From our verified records: the Schlage Encode Plus flags low battery in the app at 20% and critical at 8%. The Yale Assure Lock 2 Plus notifies at 25%, then sends daily emails and push alerts as it drains. August pushes an early low-battery notification. And the eufy FamiLock falls back to backup cells for PIN-only entry when its main pack runs flat. A dead battery is almost always a surprise you were warned about.

How do you open a key-free smart lock with a dead battery?

With emergency external power. The Yale Assure Lock 2 Plus has two exterior contact pads — hold a 9V battery against them and the keypad powers up long enough to enter your code. The Schlage Sense Pro and the eufy FamiLock use a USB-C port instead: press any phone power bank to it. These locks have no keyway at all, so the emergency-power path is the fallback — it's worth knowing before you need it.

Do rechargeable smart locks have the same problem?

They shift it. The Aqara U200, eufy FamiLock, and SwitchBot Lock Ultra use rechargeable packs (roughly 5–12 months per charge) instead of disposable cells, so there's nothing to buy. You do need a charging routine, though. And a pack that hits zero still needs its backup path: existing key for the retrofits, USB-C emergency power and AAA cells on the eufy. The SwitchBot also keeps a CR123A backup cell and a small supercapacitor for a few emergency unlocks.

Which smart lock batteries last the longest?

From our records, the Yale Assure Lock 2 Plus leads at about 18 months on 4 AA cells. The Level Lock Pro (single CR2) and SwitchBot Lock Ultra (rechargeable) land near a year. The short pole is the August Wi-Fi lock at about 3 months on 2 CR123A cells — its #1 owner complaint. Most of the rest sit in the 6-month range.

Sources for this guide

Product facts in this guide come from our provenance-tracked research records — every claim traces to a named source with the date we verified it. Dates matter: ratings, prices, certifications, and compatibility can change after we check them, so read anything time-sensitive as true as of the date shown, not guaranteed current. Spot something stale? Tell us and we'll fix it.

Yale Assure Lock 2 Plus — record last verified 2026-08-20 · 11 sources, cited in full on its profile
Schlage Sense Pro — record last verified 2026-08-08 · 14 sources, cited in full on its profile
Schlage Encode Plus — record last verified 2026-08-08 · 16 sources, cited in full on its profile
August WiFi Smart Lock (4th gen) — record last verified 2026-08-07 · 16 sources, cited in full on its profile
Level Lock Pro — record last verified 2026-08-08 · 15 sources, cited in full on its profile
eufy FamiLock S3 Max — record last verified 2026-08-09 · 19 sources, cited in full on its profile
Aqara Smart Lock U200 — record last verified 2026-08-11 · 22 sources, cited in full on its profile
SwitchBot Lock Ultra Vision Pro Combo — record last verified 2026-08-08 · 12 sources, cited in full on its profile