If you want to use home Wi-Fi during a power outage, first check which devices need power and for how long. A UPS can supply power to the devices connected to it, but that does not mean the upstream network equipment or mobile base stations will keep running. In a rental home, you also need permission before connecting one to building equipment or a shared outlet.
List the devices that must stay on
Check the equipment labels and the diagram for your home internet connection. Besides a Wi-Fi router, your setup may include an ONU, modem, or home gateway. If an upstream device loses power, keeping only the router on may not keep your internet connection available.
| Device | Check first |
|---|---|
| Your Wi-Fi router | Power adapter voltage, current, power use, and plug type |
| ONU, modem, or home gateway | Who owns it, whether it needs power during an outage, and whether you may power it |
| Computer or other device | Whether it must run during the outage; adding it changes total load and runtime |
Voltage and current printed on a power adapter describe its input rating. They do not necessarily equal the device's actual power use or the UPS runtime. Use the manufacturer's stated power consumption when available. If you cannot find it, ask the manufacturer or property manager.
Check whether the network will remain available
A UPS supplies power only to the devices plugged into it. If a shared router in the building, the provider's equipment, or network equipment outside the building stops during an outage, powering your own router may not restore internet access. Ask the rental property or internet support desk: “Will the upstream equipment remain powered during an outage?” and “May I connect a UPS to my equipment?”
Do not connect a UPS to shared equipment, equipment managed by someone else, or a shared outlet without permission. Do not change the power or cabling of rental equipment. If the permitted setup is unclear, wait before buying.
Compare power use and required runtime
- Check the model and manual of each device you want to power. Record the number of devices and their power use in watts (W).
- Add the watts for devices that will run at the same time. The total must stay within the UPS's maximum output in W. VA and W are different ratings, so check both.
- Decide how long you need power and check the manufacturer's runtime chart for that load.
- Allow for differences caused by battery condition, temperature, and battery age. Also consider what you will do if the outage lasts longer.
As one product example, the APC ES BE425M-JP is rated at 425 VA/255 W. Schneider Electric's standard runtime table lists about 28 minutes at a 60 W load. This is a reference value; actual runtime varies with battery charge, temperature, and age. The product page warns about connecting equipment with a power factor correction (PFC) power supply and says the battery is not replaceable. Consider this model only after checking the power type, runtime need, and replacement terms for your own setup. Check the BE425M-JP specifications and listing on Rakuten. Check the seller for current price, stock, and return terms.
Check rental restrictions before buying
- Can you place the UPS where the manual's ventilation, temperature, and clearance requirements can be met?
- Will you connect only your own equipment? Do you have permission to power any supplied or shared equipment?
- Can the UPS and cables be placed without blocking a walkway, and do they fit the outlet and circuit conditions?
- Does the combined wattage and required runtime fit the UPS rating?
- Have you checked the battery, warranty, and disposal terms?
If the upstream network may stop, or permission, load, or placement conditions are unknown, ask the property manager or internet support desk instead of buying a UPS. For steps to record a connection failure after an outage, see “What to Record Before Contacting Support When Rental Internet Stops Working.”
Official sources checked: October 25, 2026.
