When a hotel loses utility power or its internet connection, what keeps functioning depends entirely on which pieces of the stack are battery-powered at the door, which equipment sits on a UPS, and which cloud services have a local fallback. Guest-room locks generally keep granting access because they run on local batteries, independent of building power. A cloud PMS, guest Wi-Fi, and networked room controls are a different story — they depend on the local controller, the network gear, and the WAN link staying up, which is a design decision an integrator makes well before opening day, not something to discover during the first outage. This is the kind of continuity planning that should be part of any hospitality technology design review, not an afterthought bolted on after a property has already opened.
Do guest-room locks keep working if the power goes out?
Yes, in most cases, because the locks themselves are battery-powered and make access decisions locally rather than depending on continuous communication with a server. Salto's own documentation on its lock platforms explains that its wire-free locks "can operate autonomously for months on battery power" and are built so that "access functionality works without needing to be connected and can continue operating independently during temporary communication disruptions" (How Salto KS and Salto Space handle connectivity disruptions). The lock reads the credential, validates it against data stored on the card or in the lock itself, and opens the door — none of that requires mains power or a live network link at the door.
Where this gets more complicated is the controller that manages those locks. On a Salto KS deployment, the on-site IQ controller requires mains power, and Salto's own FAQ confirms that it "will go offline during a power outage" unless it sits on a UPS or alternative power source. If the IQ goes down, only locks specifically configured for Offline Access continue granting entry using permissions already stored locally; locks without that configuration may not. On Salto Space, the architecture is built differently around a Data-on-Card model, where "smart stand-alone locks make access decisions locally without requiring continuous communication" to any central controller at all — a meaningfully more resilient posture during an extended outage, according to the same source.
The practical question for a GM or director of engineering to put to their integrator is not "do the locks have batteries" — they almost certainly do — but which specific locks are configured for offline access, whether the IQ or Space server sits on a UPS, and what happens to new credential issuance (a guest checking in mid-outage) versus locks that are already keyed.
What happens to the PMS and keycard encoding when the internet drops?
A cloud-hosted PMS stops being reachable the moment the property's WAN connection drops, which means no new check-ins, no new keycard encoding, and no real-time room-status updates until connectivity is restored. This is a structural limitation of cloud PMS architecture, not a flaw specific to any one vendor — the system simply cannot talk to a server it cannot reach. Properties should ask their integrator what a documented manual fallback looks like: a paper or offline check-in process, and how guests already keyed before the outage are affected (generally not at all, since their credentials already exist on-card or in the lock).
Salto's Space platform offers a specific mitigation worth asking about directly: "you can continue issuing room keys to guests without needing the software or encoder by using the spare keys feature," according to Salto's own Space FAQ. That is the kind of detail that only matters if it has been tested before an actual outage, not discovered during one — confirm with your integrator whether spare keys are provisioned, stored securely at the front desk, and whether staff know the manual procedure for using them.
Which equipment should sit on a UPS versus a generator?
This is a question to work through with your electrical contractor and integrator together, because the right split depends on the property's existing emergency power infrastructure, local code, and how long an outage realistically needs to be bridged. As a starting framework: equipment that needs to survive a brief outage without interruption — the access control controller (Salto IQ or Space server), core network switches, and the Wi-Fi controller — are reasonable UPS candidates, since a UPS bridges the gap in seconds rather than the minutes it typically takes a generator to start and stabilize. Equipment with a longer runtime need, or loads too large for a reasonably sized UPS, belongs on generator power once it comes online.
Runtime targets should be set deliberately rather than assumed. A UPS sized only to "ride through" the few seconds until generator power kicks in serves a different purpose than one sized to carry critical systems through a genuinely multi-hour utility outage with no generator at all. That distinction — bridge power versus sustained backup — should be explicit in the design, because undersizing a UPS for the wrong scenario is a common planning gap.
What should be tested before opening, not discovered during an outage?
An integrator should run a deliberate outage drill before a property opens, not assume the design works because the spec sheet says so. That means physically cutting power to the access controller and confirming which specific locks still grant access and which don't; pulling the WAN connection and timing how long guest Wi-Fi, the PMS connection, and any networked room controls take to fail, and what staff see on their end; and confirming the spare-key or manual check-in fallback actually works end to end, including whether front-desk staff have practiced it. Properties already engaged on guest-room automation and PMS integration work with Cave Group can fold this outage test into the same commissioning punch list used for day-one acceptance, rather than treating it as a separate exercise months later.
Frequently asked questions
Do hotel door locks stop working in a power outage?
Generally no — most hotel electronic locks are battery-powered at the door and make access decisions locally, so they keep functioning during a utility power outage independent of building power, according to Salto's own documentation on its lock architectures.
Can guests still check in if the hotel's internet goes down?
Not through the normal cloud PMS workflow, since a cloud PMS requires connectivity to encode new keys and update room status. Ask your integrator whether a manual fallback such as Salto's spare-keys feature is provisioned and whether staff have practiced using it.
Does the access control server need a UPS?
That depends on the property's outage tolerance and should be worked out with your electrical contractor and integrator, but since Salto's IQ controller is confirmed to go offline during a power outage without a UPS or alternative power source, keeping it powered is generally worth discussing for any property that wants offline-access locks to keep validating new permission changes.
What is the difference between Salto Space and Salto KS during an outage?
Salto Space uses a Data-on-Card architecture where locks make access decisions locally without needing continuous communication to any central controller, while Salto KS is cloud-based and relies on locks specifically configured for Offline Access, or a powered IQ controller with locally stored credential data, to maintain continuity when connectivity drops.
Should every piece of hotel technology be on backup power?
No — treat it as a tiered decision. Short-bridge items like the access controller and core network switches are reasonable UPS candidates, while sustained operation during a longer outage is a generator-level decision; the right split depends on your property's specific infrastructure and should be confirmed with your electrical contractor and integrator rather than assumed.