139 plain-language answers in 11 topics, taken from the guides on this site. Search for a question, pick a topic, or read straight through, and follow the links when you want the full story.
A smart home is a set of sensors and actuators tied together by a hub that runs your rules. Which radio each device uses, whether Zigbee, Z-Wave, Thread or Wi-Fi, decides what you need to plug in. Matter is the layer that lets ecosystems share devices, and local control is what keeps things working when the internet, or a vendor, does not. When something misbehaves, check the battery, the signal path and the pairing state first.
What a smart home is made of, and the handful of ideas everything else builds on.
A home where everyday devices such as lights, plugs, heating, locks and sensors can be controlled from an app or by voice, and can also act on their own through rules you set. Three parts do the work: sensors measure things, actuators (relays, motors, valves, locks) do something physical, and a controller, usually a hub, ties them together and runs your automations.
The controller at the centre of a smart home. It speaks one or more protocols, remembers which devices you have paired, and runs your automations. Some hubs are dedicated boxes, some are built into speakers or displays, and some are software that runs on your own hardware.
Read more All 29 hubs we profile Hub Advisor
It depends on how the devices connect. Wi-Fi devices work with your router and their own app, so they need no hub. Zigbee and Z-Wave devices need a hub that acts as the controller. Thread devices need a Thread border router. Matter devices need a Matter controller, which is often a speaker, display or phone you already own.
Read more Protocols compared
A hub runs your devices and automations. A bridge translates between two protocols or ecosystems, for example exposing Zigbee devices to Matter. A gateway is broadly interchangeable with either, because brands use the words inconsistently. When in doubt, check what the box actually does rather than what it is called.
Read more Matter bridges explained
A platform built around a phone app and a voice assistant, usually free with the devices you buy. The big four are Amazon Alexa, Google Home, Apple Home and Samsung SmartThings. Each can act as the controller for your devices, and Matter is what lets one device work with several of them.
Read more Hubs by category
No. Alexa, Google Assistant and Siri are an input method, a way to give commands. The hub runs the logic: the schedules, conditions and automations. Many homes benefit from both, and moving your automation logic to a local hub does not mean giving up voice control.
Read more Hubs
A sensor measures: motion, an open door, temperature, humidity, a leak, air quality. An actuator does something physical: a relay, a motor, a valve or a lock. Sensors are the input layer of every automation and actuators are the output.
Read more Glossary
A saved rule that runs without you. It has a trigger (the event that starts it, such as motion, a door opening, sunset or a button press), optional conditions ("only if it is dark") and one or more actions (turn on a light, send a notification, close a valve). Platforms use different names: Flow on Homey, Routine on Alexa and Google, Automation on Home Assistant and Apple Home.
Read more Automation recipes Motion lighting that nobody resents
A scene is a saved set of device states that is recalled together, such as a "Movie night" scene that dims lights and closes blinds. It does not decide when to run. An automation decides when: something triggers the scene, or triggers a set of actions directly.
Read more Glossary
Local control means commands and automations are handled on your own network with no cloud round-trip. It is the single most important attribute for reliability, because it keeps working during an internet outage or if the manufacturer shuts its service down. It is also faster: local processing is typically tens of milliseconds, while a cloud round-trip can take a second or more, which is very noticeable on a light switch.
Read more Hubs: local vs cloud When the internet drops
A cloud-dependent device or platform sends its commands through the manufacturer's servers, so it stops working when your internet or that service is down. It is the opposite of local control. Cloud-dependent devices are not automatically bad, but you should know which ones you own.
Read more Glossary When the internet drops
Only the local parts will. Devices and automations that run through your hub on your own network keep working. Anything that routes through a manufacturer's cloud, including many cameras and consumer ecosystems, does not. And local control only protects you from internet outages, not power cuts: if the hub and router lose power, nothing runs unless they are on a small UPS.
Read more Troubleshooting: power cuts When the internet drops
That is called end of life. For a cloud-dependent device it can mean the device stops working entirely. Devices with local control are largely protected from this, because they do not need the vendor's servers. It is one of the strongest arguments for choosing local-control devices.
Read more Glossary: end of life When the internet drops
Whether devices from different brands genuinely work together. It has been the central problem of the smart home, and it is the problem Matter was created to solve.
Read more Compatibility checker Matter
Choosing between ecosystems, dedicated hubs and self-hosted software, and what changes when you switch.
There is no single best, because "best" depends on whether you value breadth, simplicity or local-only control. In our review roundup, reviewers point to Homey Pro for the broadest protocol support, Home Assistant for power and customisation, SmartThings for the friendliest start, and Hubitat as a local-only middle ground. Our Hub Advisor narrows the choice to your situation.
Read more Hub reviews and scores Hub Advisor Compare hubs
We group the 29 hubs we profile into categories: beginner-friendly entry points, platforms for tinkerers, consumer ecosystems (Alexa, Google Home, Apple Home, SmartThings), dedicated all-in-one hubs, open-source platforms, professional and building-automation systems (such as Loxone, KNX and Homematic IP), and budget or legacy RF. Several hubs genuinely belong in more than one group.
Read more Hubs by category
The largest open-source home automation platform by integration count. It is free, fully local and needs no mandatory account, and it has the steepest learning curve of any mainstream option. An optional Nabu Casa subscription adds remote access and voice.
Read more Home Assistant on the hubs page
No, but they combine well. A common setup is to let a local hub take over the automation logic while Alexa or Google keep working as voice front-ends. Because you are adding a layer rather than replacing one, nothing needs to be unpaired.
Read more Troubleshooting: migrations
Yes, with a caveat. With Matter, one device can belong to several ecosystems at once (multi-admin), so the same plug can be live in Alexa and Apple Home. Zigbee and Z-Wave devices are different: each belongs to one network at a time and must be removed from the old hub before joining a new one.
Read more Matter multi-admin
Mostly tedious rather than difficult. The work is unpairing and re-pairing Zigbee and Z-Wave devices one at a time, and rebuilding your automations. Matter devices are far easier thanks to multi-admin, because they can run in two systems while you move. The universal rule is to exclude or factory-reset each device from its old hub before pairing it to the new one.
Read more Migration guides
No. A hub sets the floor of your privacy and reliability, not the ceiling for every attached device. A cloud camera on a local hub still depends on the manufacturer's cloud. If the camera offers RTSP or ONVIF you can connect through that instead.
Read more Troubleshooting: cloud camera offline
A hub that speaks several radio protocols natively. Homey Pro is the broadest example in our list with seven, while most hubs manage two to four. The benefit is fewer boxes; the trade-off is that everything depends on that one hub.
Read more Which hubs speak which protocols
The drivers that teach a hub to talk to a particular brand or service. Home Assistant calls them integrations. On Homey they are called apps, which is different from a phone app. How large that catalogue is matters when you pick a platform, so check that your key devices are supported before committing.
Read more Glossary
Yes. Backing up your device pairings and automations is critical before firmware updates, and it is the difference between a five-minute and a five-hour recovery after a hub failure.
Read more Glossary: backup and restore
How devices actually talk to each other: Zigbee, Z-Wave, Thread, Wi-Fi, Bluetooth and the rest.
The language devices use to communicate. Our protocols section covers ten of them: Matter, Zigbee, Z-Wave, Thread, 433 MHz, Bluetooth/BLE, infrared, Wi-Fi, Ethernet and the local network. They are not all the same kind of thing: some are radios, some are wires, and Matter is a layer that sits on top of other links.
Read more Protocols
Zigbee is a low-power mesh protocol on 2.4 GHz, built on the IEEE 802.15.4 radio standard. One device, the coordinator (normally built into your hub), forms and manages the network. Mains-powered devices act as routers and relay other devices' messages, while battery devices are end devices that sleep between reports. The mesh is self-healing, so if one relay disappears messages find another route. Traffic is encrypted with AES-128, and Zigbee has the largest device catalogue of any smart home radio.
Read more Protocols Glossary: Zigbee
The coordinator forms and manages the network and there is exactly one per network. A router is a mains-powered device that relays traffic for others (not to be confused with your internet router). An end device is a battery device that sleeps and does not relay anything, so sensors and buttons do not extend your mesh.
Read more Glossary
The unified Zigbee certification that replaced earlier fragmented profiles. It greatly improved cross-brand compatibility, so it is the version to look for.
Read more Glossary
Z-Wave is a mesh protocol on sub-1 GHz frequencies, so it avoids competing with 2.4 GHz Wi-Fi traffic. It needs a hub as its controller, and the Z-Wave Alliance enforces strict interoperability certification across brands. Like Zigbee, it uses mains-powered repeaters and AES-128 encryption. A classic Z-Wave network is limited to 232 nodes, which only matters in very large installations.
Read more Protocols
Z-Wave is region-locked by frequency: roughly 868 MHz in the EU and 908 MHz in North America. The radios physically cannot hear each other and there is no software fix. This applies to hubs too, so a US hub will not run EU Z-Wave devices either. Check the region marking before you buy, especially when importing.
Read more Troubleshooting: imported Z-Wave device
Z-Wave Plus is a certification tier that brings better battery life, range and over-the-air update support, so it is effectively the baseline to look for. Z-Wave Long Range (LR) is a newer variant that trades mesh networking for much greater point-to-point range, useful for outbuildings, gates and large properties.
Read more Glossary
A low-power, IPv6-based mesh protocol built on 802.15.4, designed as the radio backbone for Matter. Thread radios sleep most of the time, which suits battery sensors and locks that should not need new batteries every few months. It needs at least one Thread border router on the network.
Read more Matter over Thread explained
It is the gateway between the Thread mesh and your Wi-Fi or Ethernet network. Without one, Thread devices can talk to each other but not to your phone or hub. Many everyday devices already include one, typically smart speakers and displays, streaming boxes, some Wi-Fi routers and some hubs. Not every model has the radio, so check the spec sheet for "Thread border router".
Read more Thread border routers explained
No, although they use the same kind of radio (IEEE 802.15.4 at 2.4 GHz). A Zigbee device cannot join a Thread network and the other way round. They differ above the radio, in how messages are routed and what they mean.
Read more The smart home stack
An application-layer standard from the Connectivity Standards Alliance that defines what a device is and how it is controlled. One certified device can work across Alexa, Google Home, Apple Home and SmartThings. Matter is not a radio protocol: it runs over Wi-Fi, Thread or Ethernet.
Read more Protocols
No. Matter standardises the top of the stack and the onboarding step, and leaves the radio to Wi-Fi, Thread or Ethernet. Zigbee and Z-Wave are complete stacks of their own, which is why "Zigbee or Matter?" is the wrong first question. Existing Zigbee and Z-Wave devices can join the Matter world through a bridge.
Read more The smart home stack Matter bridges
A network where devices relay each other's traffic, so coverage grows as you add mains-powered devices. Zigbee, Z-Wave and Thread are meshes; Wi-Fi is not, although mesh Wi-Fi systems extend a router.
Read more Glossary
It is simple, because devices connect directly to your existing router and need no hub, and it has plenty of bandwidth for cameras and displays. The trade-off is power: each device draws more than a mesh radio, which is why most battery sensors avoid Wi-Fi in favour of Zigbee, Z-Wave or Thread. It suits always-powered devices such as plugs and cameras.
Read more Protocols
Most smart home devices do not support 5 GHz. The 2.4 GHz band also travels through walls better. On a router that combines both bands under one name, some devices fail to pair, and temporarily splitting the two bands is a standard fix.
Read more Glossary: 2.4 GHz, 5 GHz, dual-band Getting signal into the garden, shed and garage
A short-range, low-power version of Bluetooth used by locks, sensors and wearables, with a typical range of about 10 to 30 metres. Phone-proximity features such as auto-unlock and presence detection almost always rely on it. Without a bridge, BLE devices generally cannot be controlled from outside the home.
Read more Protocols
A simple, often one-way radio protocol used by many older and budget European plugs, blinds and remotes, including KlikAanKlikUit. It is typically unencrypted, has no mesh and gives no delivery confirmation. It is cheap and fine for low-stakes jobs, but a poor foundation for anything security-sensitive.
Read more Protocols
Controlling legacy gear that has no other smart connectivity: TVs, air conditioners and AV equipment. A hub adds it through an IR blaster. It is one-way and line-of-sight, so the hub cannot confirm that the device actually responded.
Read more Protocols
Thread, Zigbee or Z-Wave. They offer low power and a mesh. Wi-Fi battery sensors usually last months rather than years because the radio draws far more power.
Read more Which one for what
Thread, Z-Wave or Bluetooth LE are the usual choices. Look for strong encryption and a local fallback, so the lock still works when the network does not.
Read more Smart lock guide Smart locks
Rough figures for a typical home: Zigbee and Thread about 10 to 20 m per hop, Z-Wave about 30 m per hop indoors, Bluetooth LE 10 to 30 m, Wi-Fi 20 to 50 m indoors, and infrared a few metres in line of sight. Walls, materials and interference change real-world range a lot, and mesh protocols extend further because each mains-powered device relays for the others.
Read more Protocols compared Getting signal into the garden, shed and garage
Zigbee, Z-Wave and Thread are secured with AES-128, which is why a modern mesh device is far harder to spoof than a legacy 433 MHz one. Most 433 MHz and infrared devices are one-way and unencrypted.
Radio bands below 1 GHz, such as 433, 868 and 915 MHz. Compared with 2.4 GHz they penetrate walls better and are less congested, at lower data rates. They are regulated per region, which is why some devices are region-locked.
Read more Glossary
Adding devices, sharing them between apps, and telling the three Matter roles apart.
Matter is designed to work across Alexa, Google Home, Apple Home and SmartThings with one certification, and Home Assistant can act as a Matter controller too. One device can be shared with several of them at once.
Read more Protocols: Matter
Three different jobs, often combined in one box. The controller adds devices, keeps the device list and runs automations; you need one for any Matter device. The Thread border router connects the Thread mesh to your home network; you need one for Matter-over-Thread devices. The bridge makes non-Matter devices, such as Zigbee or Z-Wave, appear as Matter devices.
Read more Three jobs compared
Wi-Fi suits mains-powered devices that need bandwidth, such as plugs, bulbs, light strips and cameras, and needs no extra hardware beyond a controller. Thread suits low-power devices such as door sensors, locks, buttons and blinds, and needs a border router. The two sit side by side in one home: Thread for sensors and locks, Wi-Fi for the mains-powered rest.
Read more Matter over Wi-Fi Matter over Thread
No. Only for Matter-over-Thread devices. Matter over Wi-Fi and Matter over Ethernet need no border router.
Read more Thread border router
Scan the QR code or type the setup code from the device. Your phone talks to the device over Bluetooth LE and hands over your Wi-Fi or Thread network details, and the device then joins and shows up in your app. From then on it talks over Wi-Fi or Thread.
Read more How adding works
Yes. You may need it again. A sharing code for adding the device to a second ecosystem is generated separately by the app that currently owns the device.
Read more Glossary: QR setup code
This is called multi-admin. In the app that currently owns the device, generate a fresh sharing code and scan or enter it in the second app promptly, because sharing codes usually expire within minutes. Do not re-scan the sticker. Many devices support 3 to 5 ecosystems (fabrics), and once the limit is full you must remove one before adding another.
Yes, through a Matter bridge, which makes each device appear as an ordinary Matter device. For most homes the bridge is the realistic way to adopt Matter step by step. Many Zigbee and Z-Wave hubs and lighting bridges can act as one, including those from Philips Hue, IKEA and Aqara. Expect fewer features, because Matter may not expose every setting.
Read more Matter bridges explained
Buying new devices as Matter gives the simplest and fullest support. Bridging suits you when you already own a working Zigbee or Z-Wave system. And some devices need features Matter does not offer yet, so it is fine to leave those in their own app or hub.
Read more Three ways to get a device into Matter
Keep the controller and devices on the same network, because Matter relies on local discovery, which separate guest or IoT networks often block. Make sure IPv6 is enabled on the local network (most routers do this by default). For Wi-Fi devices you need a 2.4 GHz-capable network with good signal where the device sits.
Read more Tips for a stable setup
Use more than one border router so the mesh survives if one is switched off, and prefer recent ones, since older ones sometimes create a separate Thread network instead of joining yours. Spread mains-powered Thread devices around the house as relay points, and give border routers a wired Ethernet connection where you can.
Read more Tips for a stable Thread network
Everything behind it goes offline too. That is the cost of a bridge: one more thing that must stay on. Keep its firmware up to date and use wired Ethernet for it where you can.
Read more Keeping a bridge healthy
What to check before you buy, and the small details that decide whether a device works in your home.
A short checklist drawn from our guides: which protocol it speaks and whether your hub supports it; whether it works locally or needs the cloud; whether a subscription is hiding behind a headline feature; the regional version, for Z-Wave; certification marks; the bulb fitting or IP rating where relevant; and what happens when the manufacturer stops supporting it.
Read more Best Buys guides Compatibility checker Smart locks
No. Certification is formal testing that a device meets a standard, such as Matter, Zigbee 3.0 or Z-Wave Plus. Uncertified "compatible" devices may work but are not guaranteed to. Check the specific model against your hub.
Read more Compatibility checker
A smart plug switches and measures anything on a mains lead. A switch module (relay) sits behind an existing wall switch or inside a fitting, so your original faceplate and manual operation keep working. A smart bulb screws in and goes, but the wall switch can then cut its power.
Read more Smart plugs Switches & dimmers Smart bulbs Smart plugs
A smart switch replaces the wall switch itself, so the room still works by hand and every bulb on that circuit is covered. Smart bulbs are the simplest way into smart lighting and add colour or tunable white, but a conventional switch can then cut their power. Our guides cover both approaches.
Read more Smart bulbs Switches & dimmers Ten smart lighting mistakes, and how to avoid them
Getting the fitting wrong is the most common smart bulb buying mistake. Common types are E27 and E14 screw fittings (Europe), B22 bayonet (UK), GU10 and MR16 spotlights, and E26 (North America). Check your existing bulb before ordering.
Read more Glossary: bulb base
Not all bulbs are dimmable, and pairing a dimmer with a non-dimmable LED causes flicker and buzzing. Check that both the bulb and the dimmer support dimming.
Read more Glossary: dimmer Dimming without the flicker and buzz
Lumens (lm) measure how much light a bulb emits, and are the number that matters when replacing an old bulb: roughly 800 lm equals a traditional 60 W incandescent. Kelvin (K) is the colour temperature, and lower numbers look warmer: 2700 K is cosy yellow, 4000 K neutral and 6500 K cold daylight. Watts no longer indicate brightness on LEDs.
Read more Glossary: lumen, Kelvin, CCT Why your LEDs look wrong
The colour rendering index scores how accurately a light renders colour, out of 100. Above 90 is good. Cheap smart bulbs often sit in the 80s, which makes skin tones and food look slightly off.
Read more Glossary: CRI Why your LEDs look wrong
Colour bulb configurations. RGBW adds a dedicated white LED to red, green and blue; RGBCCT adds tunable warm and cool white. Dedicated white channels produce far better whites than mixing RGB.
Read more Glossary LED strip and concealed lighting, done so it lasts
A common wire supplies continuous power to a thermostat. Many older homes lack one, which is the single most common smart thermostat installation blocker. Some thermostats ship a power-extender kit to work around it.
Read more Smart thermostats
A communication standard between a thermostat and a modulating boiler that lets the boiler run at partial output rather than simply on or off. It is more efficient and more comfortable, and common in European heating.
Read more Smart thermostats Heating controls that actually save money
A motorised thermostatic radiator valve (TRV) that replaces the manual knob and gives per-room temperature control in homes with no heating zones. It is the cheapest route to room-by-room heating in older European housing.
Read more Smart radiator valves Zoning your heating without spending a fortune
A motion sensor (PIR) detects movement through changes in heat. It is cheap and battery-friendly, but a motionless person becomes invisible to it. An mmWave presence sensor uses radar and detects a person who is present but perfectly still, at the cost of higher power draw, so it is usually mains-powered. The two fail in different ways, which is why combining them cuts false triggers.
Read more Motion & presence sensors Motion lighting that nobody resents
eCO2 is an estimate derived from VOC readings, not a measurement. Cheaper air quality monitors report it. An NDIR sensor measures actual CO2, and it is the one to pay for if you plan CO2-triggered ventilation. CO2 is the number worth watching first.
Read more Air quality monitors Why afternoon meetings feel worse
PM2.5 is airborne particles under 2.5 micrometres, the fraction most associated with health effects. VOC (volatile organic compounds) are airborne chemicals from paint, cleaning products and furnishings.
Read more Air quality monitors Indoor air quality
A smart lock's physical security comes from the deadbolt body and strike plate, not its software, which is why a full-grade deadbolt matters more than a feature list. Choose one that keeps working when the network does, and check what a subscription would remove.
Read more Smart locks Device reviews Smart locks
Look for RTSP or ONVIF support, which lets any hub or NVR record the stream without the manufacturer's cloud. PoE (Power over Ethernet) cameras are the preferred installation: one cable for power and data, with no batteries and no Wi-Fi congestion. An NVR records footage locally.
Read more Smart cameras Glossary: RTSP, ONVIF, NVR, PoE Cameras and privacy
Ingress protection, written as two digits: dust resistance, then water resistance. IP44 handles splashes, IP65 handles jets and IP67 handles submersion. Check it before putting anything outdoors.
Read more Glossary: IP rating Where to put an outdoor camera, and how to keep it weatherproof
Our guides point to a few good first steps. Smart thermostats are described as the fastest payback of any smart device, if they match your boiler. Water leak detectors are the cheapest insurance in the house. A single metering smart plug can start an audit of your biggest energy wasters. Whichever you pick, choose the hub or ecosystem first, because it decides which protocols you can use.
Read more Hub Advisor Best Buys Door and window sensors
Measuring electricity, EV chargers, solar and batteries.
Energy monitoring is the prerequisite for any serious energy-saving effort. You can measure per device with a metering smart plug or the whole home with a P1 reader or CT clamps.
Read more Energy meters Choosing energy monitoring
A standardised data port on smart electricity meters in the Netherlands and much of Europe. A P1 reader gives exact whole-home consumption straight from the meter, which is more accurate than CT clamps.
Read more Energy meters Getting your own data out of a smart meter
A current transformer that clips around a live cable to measure power draw without breaking the circuit. Whole-home energy monitors use it where no P1 port is available.
Read more Energy meters Choosing energy monitoring
Use a metering smart plug on one device at a time, with a hub that logs history. Our phantom-load recipe walks through finding your three biggest wasters. Remember that watts on a plug's label are a load rating, not a measurement of what the device actually draws.
Read more Automation recipes Find your standing load
Load balancing is the feature that stops your main fuse tripping. OCPP (Open Charge Point Protocol) support is also worth checking, because it means the charger is not locked to one vendor's app or backend.
Read more EV chargers Charging an electric car at home, properly
Yes. Our guide describes the inverter, not the panels, as what decides what you can automate. An inverter with a local API is what makes recipes such as diverting solar surplus to the hot water cylinder possible.
Read more Solar inverters Energy storage Solar panels
Building rules that are helpful rather than annoying.
Our collection has 90 practical recipes in nine categories: Energy, Safety & Security, Health, Outdoor, Comfort & Climate, Lighting, Water, Access and Appliances Control. Each one names the trigger, the logic that makes it reliable and the hardware you need.
Read more Automation recipes Leak detection and automatic shut-off
A condition is a test between the trigger and the action, such as "only if it is dark" or "only if nobody is home". Conditions are what separate a useful automation from an annoying one.
Read more Glossary: condition
Geofencing uses your phone's location to trigger automations when you enter or leave an area. Two radii work better than one: a wide zone to pre-heat as you approach, and a tight zone for arrival itself.
Read more Glossary: geofencing Presence detection
It is the most useful and also the most unreliable input in home automation. You can determine whether people are home through phone geofencing, Bluetooth or Wi-Fi presence, or mmWave, and each has its own failure modes. Combining methods helps.
A deliberate gap between the switch-on and switch-off thresholds. With a single threshold the reading hovers around it and the device cycles. Use two thresholds, for example on above 1200 ppm and off below 900 ppm, plus a minimum run time. It is essential for CO2, humidity and temperature rules.
Read more Troubleshooting: rapid cycling Heating controls that actually save money
A fixed clock time was used where solar position was needed, and sunset moves by hours across the seasons. Trigger on sunset or sunrise with an offset, combine it with a lux reading so overcast days behave sensibly, and check that your hub's location and timezone are set correctly.
Read more Troubleshooting
A time window in which an automation is suppressed or notifications are silenced. It is the simplest fix for automations that are useful by day and infuriating at 3 a.m.
Read more Glossary: quiet hours Night-time safety
The automation has no concept of manual intent. Add a short-lived override flag that suppresses it for 20 to 60 minutes when a manual change is detected, or check the event's origin where your hub exposes it. And consider whether the automation should exist in that room at all.
Read more Troubleshooting Motion lighting that nobody resents
That delay is latency. Local processing is typically tens of milliseconds, while a cloud round-trip can take a second or more. Direct device-to-device links (Z-Wave association, Zigbee binding) are faster still and keep working if the hub is offline.
Read more Glossary: latency, association, binding
A third-party cloud service that links apps and devices that do not natively talk to each other. It is convenient, but it adds a cloud dependency and latency to anything routed through it.
Read more Glossary: IFTTT
Open-source software for people who run their own systems. Zigbee2MQTT bridges a Zigbee USB dongle to any MQTT-capable platform, bypassing vendor hubs entirely, and is popular with Home Assistant users. Z-Wave JS is the modern open-source Z-Wave driver used by Home Assistant and others, which replaced the older OpenZWave project.
Read more Glossary
The usual causes, in the order they are most likely, taken from our symptom-based troubleshooting guide.
In order: the battery (replace it, do not trust the percentage), the signal path (is there a mains-powered repeater between it and the hub?) and the pairing state (is it still joined to an old hub?). Those three account for the large majority of faults across every protocol.
Read more Troubleshooting
Move the device next to the hub and retest. If it works there, it is a signal or mesh problem. If it still fails, it is the device or its pairing. If several unrelated devices fail at once, suspect the hub, the network or a firmware update rather than the devices.
Read more Troubleshooting
Most likely it sits at the edge of the mesh with no repeater between it and the hub. Battery devices do not relay traffic, so a house of sensors with no mains-powered devices has no mesh to speak of. Add a mains-powered device of the same protocol roughly midway, keep the device away from metal, replace the battery, and on Z-Wave run a network heal afterwards.
Read more Full fix list
Almost always add a repeater. Moving the hub fixes one dead zone and often creates another, whereas a mains-powered device mid-path strengthens the mesh permanently. Put the hub somewhere central and wired, then extend outward with plugs and bulbs.
Read more Glossary: dead zone, repeater Getting signal into the garden, shed and garage
Channel overlap. Zigbee, Thread and Wi-Fi share 2.4 GHz, and the new router has probably picked a channel on top of your Zigbee channel. Set Wi-Fi to a fixed channel of 1, 6 or 11, set the Zigbee coordinator to 15, 20 or 25, and keep the hub at least a metre from the router. Change Wi-Fi first, because changing the Zigbee channel can require re-pairing some devices.
Read more Full fix list
Most likely it is still paired to a previous hub. Zigbee and Z-Wave devices must be removed from the old network before joining a new one: run an exclusion (Z-Wave) or reset and leave (Zigbee) from the old hub, or use a "force remove" mode if the old hub is gone. Then factory-reset the device with its documented button sequence, and pair within a couple of metres of the hub.
Read more Full fix list Glossary: exclusion, pairing
Either it is a Wi-Fi sensor, which will always drain fast, or a mesh sensor is retrying transmissions because it cannot reach the hub reliably. Fixing the mesh usually restores battery life. Also check the reporting interval: every 5 to 10 minutes is plenty for most automations. Avoid NiMH rechargeables in devices expecting 1.5 V alkaline cells, because the lower voltage causes false low-battery warnings.
Read more Full fix list Getting signal into the garden, shed and garage
Alkaline cells lose capacity sharply below freezing. Use lithium batteries for outdoor sensors.
Read more Troubleshooting Getting signal into the garden, shed and garage
Local control protects you from internet outages, not power outages. Put the hub and router on a small UPS: both draw very little, so even a modest unit gives hours. Also check your devices' power-restore behaviour, because some smart plugs default to off after a cut, which can silently leave a fridge or freezer unpowered. Keep manual overrides available.
Read more Glossary: UPS When the internet drops
A PIR motion sensor cannot see a motionless person, so the "no motion for X minutes" timer expires while you sit still. Trigger the off-action on the sensor being continuously clear, increase the timeout in rooms where people sit still, and for a real fix add an mmWave presence sensor. Many PIR sensors also have a hardware cooldown of 30 to 180 seconds.
Read more Motion & presence sensors Motion lighting that nobody resents
Most likely too few border routers, or several that are not cooperating because they belong to different ecosystems. Border routers from different vendors do not always form one shared Thread network, so Apple, Google and Amazon devices may each create separate meshes. Aim for two or three border routers, on Ethernet where possible.
Read more Thread border routers
A local hub does not make a cloud device local. If the camera exposes RTSP or ONVIF, connect through that. If it does not, no hub can make it work offline, and you would need to replace it with a PoE or ONVIF-capable model.
Read more Smart cameras
Common causes: it only supports 2.4 GHz and your router combines both bands under one name, or it cannot join a WPA3-only network. Temporarily splitting the bands is a standard fix, and a mixed WPA2/WPA3 mode helps older devices.
Read more Glossary: dual-band, WPA3
Keeping a connected home private, secure and useful for years.
The hub sets the floor of your privacy and reliability posture, not the ceiling for every attached device. A local hub keeps its own automations on your network, but a cloud device attached to it still talks to its manufacturer. Check each device, not just the hub.
Processing data on the device or hub rather than in the cloud. It is faster, more private and keeps working offline.
Read more Glossary
Putting smart devices on a separate VLAN limits what a compromised device can reach, and is the standard hardening step for a large smart home. The catch is discovery: Matter relies on local discovery, which separate guest or IoT networks often block unless the router forwards it. So keep the controller and its devices on the same network.
Read more Glossary: VLAN Matter network tips Securing the smart home itself
Updates fix bugs and add features, but they can also change behaviour or privacy posture, and over-the-air updates mean a device can change after you have bought it. Back up your hub before updating, because a backup turns a bad update into a short recovery.
Read more Glossary: firmware, OTA update Securing the smart home itself
Some older smart devices cannot join WPA3-only networks, which is why routers often run a mixed WPA2/WPA3 mode.
Read more Glossary: WPA3 Securing the smart home itself
Jamming means deliberately flooding a radio band to stop devices communicating. It is a theoretical attack on wireless alarms, and is mitigated by systems that alert on unexpected radio silence.
Read more Glossary: jamming Alarm systems
It is not a good foundation. Most 433 MHz devices are unencrypted, one-way and unconfirmed, whereas a modern mesh device uses AES-128 encryption. Keep 433 MHz for low-stakes jobs such as plugs and blinds.
Read more Protocols: 433 MHz Alarm systems
Our guide calls this the one category where the smart part comes second to the alarm. Check the safety certification (EN 14604 in Europe, UL 217 in North America), which is relevant to insurance and building regulations as well as quality. CO is odourless and needs its own sensor, though many units combine both.
Read more Smoke & CO detectors Smoke and CO alarms
How WeKnowSmartHome works and where its information comes from.
WeKnowSmartHome is an editorial reference for smart home hubs, protocols, automations and buying guides. Protocol and standards claims are checked against primary sources: the Connectivity Standards Alliance (Matter), the Zigbee Alliance, the Z-Wave Alliance and the KNX Association. Hub and company details are checked against each vendor's own published information.
Read more About & methodology
No. We do not run affiliate links, so brand links in our guides go straight to the manufacturer's own site.
Read more Best Buys
We aggregate what reviewers say by category rather than a single blended score, because "best" depends on whether you value breadth, simplicity or local-only control. Third-party scores are reproduced as cited data points rather than our own testing, and Trustpilot scores are live figures that move, so we date them.
Read more Hub reviews Device reviews
Thirty buying guides, one per device category. Each explains what actually separates the products, such as which protocol they speak, where recordings are stored and whether a subscription hides behind a headline feature, and then names the brands worth shortlisting.
Read more Best Buys
Our Brands page lists every brand mentioned on the site, A to Z, with its country of origin and a map, and the Hubs page has a map of where hub makers are based.
Read more Brands A–Z Hub makers map
In our glossary, which defines 138 smart home terms in plain language, from 433 MHz to Z-Wave.
Read more Glossary
ESP32, ESPHome, WLED, mmWave and the other words you meet when you build your own devices.
A low-cost microcontroller, a tiny computer on one chip, made by Espressif. It has Wi-Fi and Bluetooth built in and costs a few euros on a small development board, which is why most DIY smart home sensors, LED controllers and buttons are built on one. You load it with firmware such as ESPHome, Tasmota or WLED, and it then shows up in your hub like any other device.
Read more DIY smart home DIY projects
They are members of the same family with different radios. The ESP32-S3 has extra processing power for voice and camera projects, with Wi-Fi and Bluetooth. The ESP32-C6 adds Wi-Fi 6 and an 802.15.4 radio, so it can also run Zigbee or Thread. The ESP32-H2 has no Wi-Fi at all: it is made for Zigbee and Thread, plus Bluetooth Low Energy, which suits low-power sensors.
Read more Project: Koala Satellite (S3) Project: RoomSense (H2)
The older and simpler predecessor of the ESP32, also by Espressif. It has Wi-Fi but no Bluetooth, fewer pins and less memory. It is still cheap and works for simple sensors, but for new projects the ESP32 is usually the better choice.
Free, open-source firmware for ESP32 and ESP8266 boards. Instead of writing code, you describe your device in a short configuration file: which sensor sits on which pin, how often to measure. ESPHome turns that into firmware and installs it, after which updates go over Wi-Fi. It works directly with Home Assistant and can also talk MQTT, so other hubs can use it too.
Read more esphome.io Project: pellet level monitor
Open-source firmware for ESP8266 and ESP32 devices, best known for replacing the factory firmware of Wi-Fi smart plugs and switches so they work locally, without the maker’s cloud. It has its own web page for settings and talks to hubs mostly over MQTT.
Read more Tasmota documentation
Free firmware that turns an ESP32 or ESP8266 into a controller for addressable LED strips, where every LED can have its own colour. You get over a hundred effects, colour palettes, presets and an app, and many hubs can control it over your network.
Read more WLED documentation LED controller cases
A small radar that uses millimetre-wave radio to notice tiny movements, even breathing. Unlike a normal PIR motion sensor, which only reacts to movement, it can tell that someone is still in the room while they sit and read or work. That makes it good for keeping lights on in a room that is in use. It can also be fooled by fans, curtains or pets, so most need some tuning.
Read more Project: DIY Zigbee mmWave presence sensor Best Buy: motion and presence sensors
Two popular, low-cost 24 GHz radar modules from Hi-Link (HLK), used in many DIY presence sensors. The LD2410 reports whether someone is present and roughly how far away. The LD2450 tracks the position of up to three people in the room, so you can define zones such as “sofa” or “desk”.
Read more Project: RoomSense
Free software that connects Zigbee devices to your system through a USB Zigbee adapter, without the brand’s own hub. It passes everything on over MQTT, which Home Assistant and other platforms can read. DIY Zigbee devices often ship a small “converter” file so Zigbee2MQTT knows what the device can do.
Read more zigbee2mqtt.io
A lightweight messaging system that many DIY devices use to talk to a hub. Devices publish messages such as “temperature is 21.5” to a central program called a broker, and anything that is interested subscribes to them. It runs on your own network, so it works without the internet.
Installing software on the chip. For DIY boards you usually connect the board to your computer with a USB cable and use a flashing tool; many projects offer a web flasher that works straight from the Chrome or Edge browser. After the first install, ESPHome, Tasmota and WLED can update themselves over Wi-Fi (OTA, “over the air”).
A breadboard is a plastic board full of holes with metal strips underneath, so you can plug in parts and wires to test a circuit without soldering. Dupont (jumper) wires have small plug connectors on the ends that fit the pins on DIY boards and sensors. Together they let you build and change a prototype in minutes.
Read more In the toolbox
The standard 35 mm metal rail inside electrical cabinets that modules click onto, such as circuit breakers and relays. DIY makers use DIN rail cases for low-voltage controllers that live in a cabinet. Work on the mains side of a cabinet belongs to a qualified electrician.
Read more Casing types
A small threaded brass sleeve that you press into a 3D-printed part with a hot soldering iron. The plastic melts around it and sets, giving you a proper metal screw thread, so a casing can be opened and closed many times without wearing out.
Read more Design tips
Both are 3D model files you load into a slicer before printing. STL is the old, universal format: just the shape. 3MF can also hold several parts, colours and print settings in one file, which is why many newer designs come as 3MF.
Read more 3D printing & enclosures
PETG is the best all-round choice for indoor electronics. PLA is the easiest to print but softens in heat and sun, so keep it for prototypes and cool spots. ASA resists sunlight and heat, which makes it the one for outdoor sensors.
Read more Filament table
Yes, as long as you stay with low voltage: USB power or batteries. Anything connected directly to mains power, or that protects you from fire, smoke or intruders, belongs in a certified product or should be installed by a qualified electrician. A 3D-printed box does not make a mains device safe.
Read more Build it or buy it?
No questions match your search. Try a single keyword such as “battery”, or clear the search box. The glossary may also have the term you need.
Answers summarise the longer guides on this site. Figures such as range are rough for a typical home, and prices and product details change, so follow the links for detail. Spot an error? Tell us and we will fix it.