Z-Wave

Z-Wave is a wireless communications protocol used primarily for home automation. It is a low-energy, low bit-rate, mesh network used to communicate from appliance to appliance. It is used for wireless control of residential appliances and other devices such as lighting, security systems, thermostats, windows, locks, etc. A Z-Wave automation system can be controlled from smartphones, tablets or computers, with a Z-Wave gateway or central control device serving as both the hub controller and an Internet gateway.

Z-Wave originated around 2005 and the technology was acquired by Sigma Designs in 2008. The business was then sold on to Silicon Labs in 2018. The Z-Wave Alliance was also established in 2005 as a consortium of companies focussed on increased adoption of Z-Wave and ensuring interoperability of any device that utilises Z-Wave.

Advantages

As a widely adopted (but proprietary) protocol, there is a wide range of equipment available on the market. More than 2400 products claimed in 2018.

Disadvantages

Manufacturers have to pay a license fee to incorporated Z-Wave technology into their products. This makes them relatively expensive.
In theory, every Z-Wave device should be compatible with every Z-Wave capable hub/controller but, in practice the implementations and feature support varies, leading to a less than ideal user experience.
Different frequencies are used in different regions around the world, meaning that you can't use (for example) equipment designed for the USA in the UK.
In the real world batteries don't last as long as manufactures claim.

Evolution

September 2020

The Z-Wave Long Range protocol was announced this month. Z-Wave Long Range (Z-Wave LR) is backward-compatible with both existing Z-Wave networks and previously installed Z-Wave devices. Most importantly, Z-Wave LR provides up to four times greater range and now supports up to 2000 devices on a single network. It also claims improved battery life with "some sensors will last 10 years on a coin cell battery" but, this will be under exceptional circumstances and for very low use applications.

CES 2019

At CES2019, the very First Z-Wave 700 series (Z-Wave Plus) products were shown by Sensative. Silicon Labs only began shipping the 700 Series on its Wireless Gecko platform in early 2019. This next-generation of Z-Wave enables longer battery life (a claimed 10 years) and longer distances (a claimed 150% increase for USA radios).

New products and services based on Z-Wave 700 are interoperable with existing, installed Z-Wave devices and gateways. Some of the key claims from Silicon Labs are:

Sub microAmp sleep power, low power communication and automatic power management, ensuring long battery life in any device. Coin cell operation is now possible, providing small-footprint sensors to be embedded virtually anywhere in smart environments, with no battery maintenance needed for a decade.
Security does not compromise battery life, with secure S2 key exchange done in less than 1s.
Devices like door locks, battery powered window blinds, etc. enjoy longer battery lifetime due to the FLiRS (frequently listening routing slave) technology, minimizing power draw while providing instantaneous wake and response times. With FLiRS, Z-Wave devices continually listen for a low-power wake up beam before consuming full operational power.
The 700 platform provides enough TX/RX power for multiple story buildings and improved sensitivity gain extends Z-Wave's direct range to 100m and mesh network range to 400m. Increased transmission power means fewer hops between devices and fewer repeaters needed, improving the energy efficiency of the entire mesh network. This is claimed to increase direct range by 150% over the 500 series in the US, and 250% for European and Asian markets.

Things To Note

Z-Wave places a limit on the number of devices you can have associated with a single Z-Wave controller and this is currently 232. This can be an issue in more advanced smart homes like our own @smartest_home, where we have 400+.