Z-Wave vs WiFi Smart Devices

A client asks why the lock you quoted needs a hub when a WiFi lock connects straight to the router. Z-Wave vs WiFi is a question about how each device joins the home: through a controller on its own low-power mesh, or directly onto the network the family streams video on. The answer changes battery life, coverage, router load and what still works when the internet drops. This guide compares the two for installers, device by device.

Z-Wave vs WiFi: two ways to join the home

A Z-Wave device never talks to the router. It joins a controller, usually the alarm panel or a smart home hub, and the controller connects to the network once on behalf of every device. A WiFi device joins the router or an access point itself and gets its own address.

For how Z-Wave compares with the other common mesh protocol, see our guide to Z-Wave vs Zigbee for security dealers.

Radio band and range through walls

In North America, Z-Wave runs in the 900 MHz region, as our Zigbee comparison details. WiFi uses 2.4, 5 and 6 GHz. Lower frequencies lose less signal over the same distance and generally pass walls and floors better.

A worked example, assuming free space, equal transmit power and the same antennas: path loss rises by 20 x log10 of the frequency ratio. From 908 MHz to 2,400 MHz that is 20 x log10(2.64), about 8.4 dB more loss. At 5,180 MHz it is about 15 dB. Real homes add wall losses on top, and real devices transmit at different powers, so treat this as a direction, not a range figure.

Z-Wave also covers distance by relaying through powered devices. If a lock at the far end of the house is weak, the fix is usually a mains-powered device in between; our guide on how to extend Z-Wave range covers the order to work in.

Battery life: why locks and sensors favor Z-Wave

A door sensor or a lock spends almost all its life waiting. Z-Wave battery devices sleep most of the time and wake to report or to check for commands, and the radio only has to carry a few bytes.

WiFi radios were built for throughput, so a device that stays connected to an access point draws more power. That is improving: the Wi-Fi Alliance says its Wi-Fi CERTIFIED 6 Release 2 features allow specific wake-up times and enable power optimization of multiple battery powered devices. Those gains depend on both the device and the access point supporting the features, so check both data sheets before promising battery life.

Where a lock goes on a door, the radio is only half the job; mounting it so the bolt runs freely matters as much, as our guide on how to install a smart deadbolt explains.

Router load and device count

Every WiFi device takes an address from the router and a client slot on an access point. A home network on a typical /24 subnet has 256 addresses; take away the network and broadcast addresses and the router itself, and 253 remain for clients. The router’s DHCP pool and each access point’s client limit may be smaller, so check both.

A whole-home automation job can add dozens of plugs, bulbs and sensors to the phones, TVs and laptops already there. Each WiFi device also adds a little background traffic. Z-Wave devices sit behind one controller, so twenty Z-Wave switches add one network client, not twenty.

If the client wants WiFi devices anyway, design the WiFi for them. Our guides to WiFi access point placement and WiFi 6 vs WiFi 7 cover coverage and capacity.

Local control vs cloud dependence

Many WiFi devices are set up and controlled through the maker’s app and online service. When the internet or that service is down, some still work from a wall button but lose app control and automations. Behavior varies by product, so read the manufacturer’s documentation.

A Z-Wave device is controlled by the hub or panel, so whether a scene runs during an outage depends on where the controller runs its rules. Many panels and hubs run them locally, while remote access from a phone still needs an internet connection. Ask the controller maker which functions work offline before you sell local control as a feature.

Interoperability and certification

The Z-Wave Alliance says Z-Wave certification ensures that certified products work together regardless of brand, including backward compatibility between versions. That is why a dealer can add certified devices from different makers to one panel. Basic commands are the most dependable; advanced features depend on what the controller supports.

WiFi certification proves a device’s radio works with WiFi networks. It does not mean two brands’ apps will control each other’s devices, so a home full of WiFi devices often means several apps.

Smart home hub vs WiFi devices: which fits the job

Use the device’s power source and data needs to decide:

• Battery locks, door and window sensors, leak and motion sensors: Z-Wave on the panel or hub.
• Lighting and switches across the house: Z-Wave, which also strengthens the mesh; check the box first for a smart switch neutral wire.
• Cameras, video doorbells, streaming audio: WiFi or a cable, because Z-Wave does not carry video.
• One or two plugs with no panel in the house: WiFi can be simpler.

On a security install, the panel usually decides: if it has a Z-Wave controller built in, the automation devices join it with no extra hub.

Where to find Z-Wave devices and panels

The Z-Wave category lists Z-Wave touchscreen deadbolts and panel Z-Wave cards, within the Security, Surveillance and Control division.

For pricing and availability, ask your sales representative through the Bursma contact page or the Columbus, Ohio branch, or open a Bursma dealer account.

Frequently asked questions