A hotel's power design should separate two different jobs: a UPS exists to bridge the seconds to minutes before a generator picks up (or to shut equipment down gracefully if there is no generator), while the generator circuit is what actually sustains the network core, PMS workstations, and lock infrastructure for the length of the outage. Sizing the UPS for hours of runtime is usually the wrong instinct — most UniFi-class rack UPS hardware is built for a short bridge, not a long sit. Electronic door locks split into two very different outage behaviors depending on whether they are standalone/offline or online, and that split should drive which devices get battery-only tolerance and which need a wired power or network path tested in advance. None of this should be assumed correct until it's proven with pull-the-plug drills before the property opens.
What should a UPS actually be sized to cover?
A UPS at the network core is a bridge device, not a backup generator substitute. Ubiquiti's own rackmount UPS-2U is rated for an 8-minute runtime at half load (500W) from a 216Wh battery, and its primary function with UniFi hardware is to trigger a Graceful Shutdown for the UNVR/UNAS rather than to keep the network running indefinitely. That number is useful for sizing conversations: if the design assumption is that the generator picks up within a couple of minutes of a utility outage, an 8-minute UPS bridge at half load is enough to ride through the transfer without an unclean shutdown of the video recorder or network appliance. If the generator start time is longer, or if the design has no generator at all, the UPS sizing conversation needs to shift toward graceful shutdown of each device rather than trying to buy enough battery capacity to simply outlast the outage. Ask your electrical contractor what the generator's actual time-to-online is under test conditions, not on the spec sheet, before committing to a UPS runtime number.
That same logic should carry to PMS workstations, key encoders, and the switches feeding them. Each should be assigned to a tier: a short UPS bridge that gets the device through a generator transfer cleanly, or — where no generator covers that circuit — a UPS sized and configured for an orderly shutdown rather than continued operation. Full details on how Cave Group scopes network infrastructure for hospitality properties, including the segmentation that keeps PMS, guest, and AV traffic on separate VLANs even when a UPS is bridging a transfer, are part of the broader hotel network design.
Which loads belong on the generator instead of the UPS?
The network core (switches, gateway, wireless controllers), PMS servers and workstations, key encoders, and the online components of the access-control system are sustained loads: they need to keep running for the duration of the outage, not just through a transfer, which puts them on the generator circuit rather than relying on UPS battery alone. Phones used for front-desk and emergency communication should be treated the same way if they depend on networked VoIP hardware rather than a separate analog line. The UPS at each of these points still matters — it is what keeps the device alive and avoids a hard reboot during the handful of seconds or minutes between utility loss and generator pickup — but the generator is what carries the load afterward.
Coordinating this split is shared work between the integrator and the electrical contractor: the integrator can specify which racks, workstations, and access-control head-ends need to land on generator-backed circuits, but the electrical contractor owns the circuiting, transfer switch configuration, and generator sizing. That handoff should be documented on the drawings, not settled verbally on site, since it is the kind of gap that only shows up during an actual outage.
How do battery-powered door locks really behave in an outage?
This is where lock architecture matters more than most pre-opening checklists give it credit for. Standalone, battery-powered locks that make access decisions locally are not affected by a building power outage at all — Salto's own explanation of its Space architecture describes locks that validate credentials and write updates using data stored on the card itself, operating independently of mains power and network connectivity, "without needing to be connected," for months on battery power alone. That is the behavior a property should expect from any door running this kind of standalone, data-on-card lock during a utility outage — the guest-room door itself generally keeps working.
The online components are the part that actually goes down. In Salto's cloud-connected KS architecture, the same source explains that the IQ controller (the bridge between locks and the cloud) requires mains power and "will go offline during a power outage" unless it has its own UPS. When that happens, only locks that have been specifically configured for Offline Access can continue granting entry using locally stored permissions — everything that depends on a live connection to the IQ, such as new access-rule changes or real-time event logging, stops working until power and connectivity return. That distinction should be a specific line item in a pre-opening review: confirm which locks are configured for offline access, confirm whether the IQ or equivalent head-end sits on a UPS, and confirm what happens to real-time events and new key issuance while it's down.
Security-system components follow a comparable split, worth confirming with whatever monitoring platform is on contract. Alarm.com's documentation notes that its panels carry a 24-hour battery backup and communicate over a dedicated cellular connection rather than the building's broadband, so a panel built this way keeps signaling during a power outage even if Wi-Fi, cable, and utility power are all down. That is a useful independent-communication-path model to hold any hotel life-safety or duress-alert system to, separate from the question of how long the UPS at the network rack needs to last.
What acceptance tests should prove the design before opening?
A pre-opening sign-off should include a pull-the-plug drill rather than relying on paper calculations. At minimum, that means: killing utility power to the rack and timing the generator's actual pickup against the UPS runtime budget; confirming the UPS triggers a graceful shutdown (not a hard crash) on any device configured for it; walking a sample of guest-room doors during the outage to confirm standalone locks still grant access; checking whether the access-control head-end lost connectivity and whether any locks configured for offline access behaved as expected; and confirming PMS workstations, key encoders, and phones either stayed up on generator or shut down cleanly rather than corrupting data. Run the drill again after the generator's automatic transfer switch settings or UPS firmware change, since those are the kinds of updates that quietly break a previously-tested sequence.
Frequently asked questions
How long should a hotel's network UPS actually run before generator pickup?
It depends on how fast the generator actually comes online, which should be measured under test rather than assumed. As a sizing reference, Ubiquiti's rackmount UPS-2U is rated for 8 minutes at half load (500W) before triggering a graceful shutdown, which is a bridge-duration number rather than a sustained-runtime number.
Do battery-powered door locks stop working when the hotel loses power?
Standalone, offline-capable locks that make access decisions locally are generally unaffected by a building power outage because they run on their own battery and do not depend on mains power or network connectivity. The part that typically goes down is the online head-end (such as a cloud gateway) feeding those locks, unless that head-end has its own UPS.
Who decides which circuits go on the generator versus just the UPS?
The integrator should specify which racks, PMS systems, and access-control components need sustained generator power, but the electrical contractor owns the actual circuiting, transfer switch, and generator sizing. That split should be documented on drawings rather than agreed verbally on site.
Does a security panel keep communicating if both power and internet are down?
Alarm.com's documentation describes panels built with a 24-hour battery backup and a dedicated cellular connection independent of the building's broadband, which is designed to keep the panel signaling even when Wi-Fi, cable, and utility power are all out.
What should a pre-opening power acceptance test actually include?
A pull-the-plug drill: cut utility power, time the generator's actual pickup against the UPS runtime, confirm graceful shutdown triggers correctly, walk guest-room doors to verify lock behavior, and confirm PMS/key-encoder systems come back up cleanly rather than with corrupted data.