What happens to smart devices when the internet goes down?
Which smart devices keep working offline and which become useless — and how to choose ones that fail gracefully.
- Difficulty
- beginner
- Time
- 15 min
- Read
- 2 min
Short answer
It depends entirely on whether the device thinks locally or in the cloud. Anything that still has a physical switch and local control keeps working; anything that routes every command through a company's servers stops.
This is the question worth asking before buying rather than during an outage. The answer varies enormously between products that look identical, and it is rarely on the box.
Step by step
- Understand the two designs.Cloud-dependent: your phone talks to a company's server, which talks to the device — no internet, no control. Local: your phone talks to the device directly over your own network — the internet is only needed from outside the house.
- Check what still has a physical control.A smart bulb in a lamp with a working switch is still a lamp. A smart bulb wired to a smart switch that needs the cloud is nothing at all. Keeping a manual override matters.
- Know the risky categories.Smart locks, thermostats, security cameras and doorbells are where an outage matters most. These are worth choosing specifically for local operation.
- Check whether a hub gives local control.Many systems work locally through a hub and only need the internet for remote access. A hub often converts a cloud-dependent setup into a locally-resilient one.
- Test it deliberately.Unplug the router for ten minutes and see what still works. Far better to find out now than during an actual outage. Most people are surprised by at least one result.
- Keep manual overrides for anything important.A physical key for a smart lock. A thermostat with real buttons. Heating and door locks are not places to depend on a working internet connection.
- Consider the router's own power.A power cut takes the router down too, so the wifi goes even if the broadband is fine. Battery-backed devices with no wifi are still offline.
- Favour local control when buying.Look for local API support, hub-based operation, or open standards. It also protects you if the manufacturer discontinues the service.
Tips
- Smart heating is the one most worth checking. A system that cannot be controlled during an outage in January is a genuine problem, not an inconvenience.
- Do the unplug test when you install something, not when it matters.
- Devices supporting open local standards tend to keep working both during outages and after a manufacturer loses interest.
Questions people ask
Do smart bulbs work without internet?
It depends on the system. Locally-controlled ones keep working on your own network; cloud-dependent ones stop. Either way, a bulb in a lamp with a physical switch still works as a lamp.
How do I know if a device needs the cloud?
Unplug your router and try to control it from a phone on the same wifi. If it works, control is local. It is the only reliable test.