Z-Wave, LightwaveRF and the Neutral Wire
Whenever when someone wants to get some Z-Wave switches through me, I’d ask them this question, “Do/Will you have a neutral wire in your light switch?” And if they are not going to do renovation or rewiring, they will ask if there is any alternative. I would tell them that Z-Wave dimmers do not require neutral wire but the kind of lights you can connect will be limited. The other alternative is that they can consider is LightwaveRF as they claim to provide switches that do not require neutral wire.
WAIT! I’m not advising against it but before you think you’ve struck the jackpot and can jump straight in do a simple retrofit with LightwaveRF, it is important to know the differences between the two.
- Simple Wireless Technology. Direct transmission, one way communication between controller to devices, no routing or acknowledgement of transmission. Command and forget similar to IR remote control except you do not need line of sight. It also has a shorter range as compared to Z-Wave.
- Nice Retrofit Switches and Sockets. The face plates are stylish and come with up to 4 gangs. Sockets also come with up to 2 gangs. The insert modules are smaller due to the simplicity of the radio (one way communication). No additional wiring or changes to the back boxes are required.
- Simple Handheld and Wifi Controllers. Comes with both handheld controllers, Wifi central controller paired with smartphone app. It lacks the sophistication of Z-Wave controllers, can only connect up to 64 devices in network.
- Lower Cost. Of course, with simpler technology and less sophisticated communication, the cost of LightwaveRF is definitely lower.
- Mesh Networking. Two way communication, all transmissions are acknowledged. Thus you are able to know the status of the devices. Each device is a signal repeater itself, thus the transmission reach a out of range devices via routing through other devices. Even without routing, the range is greater than LightwaveRF.
- Range of Retrofit Options. You can choose to install inserts modules or retrofit switches. Design of faceplates is subjective but most Z-Wave retrofit switches are not as stylish as LightwaveRF. You will need to make sure neutral wires are prewired into your existing light switch to use a Z-Wave switch. For Z-Wave dimmers, neutral wire is not required.
- Sophisticated Controllers. Comes with both handheld controllers and central controllers. There is also a handful of apps compatible with Vera or Fibaro Control Centre and the controllers offers users extensive functionality to configure your network to fit to your living habits.
- Range of Manufacturer and Products. Unlike LightwaveRF, there are over 150 manufacturers that offer a huge range of products from lighting, security, heating and power management. You do not need to stick to a single or a handful of manufacturers and the products are all compatible with the central controllers.
Now that I’ve roughly summarised the pros of both technologies, I’d like to correct one major consideration, not commonly highlighted by marketing articles.
LightwaveRF switches do not require neutral wire. This is so misleading for consumers that I have to write this article. The fact is, they do not require neutral wire because they are not on/off switches! They are all dimmers! Come on, Z-Wave dimmers do not require neutral wires too!
For dimmers, when they are “off”, there are actually current running through your lights. Just that the current is not high enough to light them up. The way Z-Wave dimmers work is also similar. In order for both Z-Wave and LightwaveRF dimmers to receive commands is to stay powered. There is no way the modules can be powered without a closed circuit. That is why Z-Wave switches need to cut off power from the light bulb and yet stay in closed circuit using the neutral wires. If you ever find a LightwaveRF true on/off switch or relay, unless it runs on batteries, it will definitely require neutral wire. I’m not an electrician but correct me if I’m wrong.
The next thing I like to point out is, if you use dimmers, regardless Z-Wave or LightwaveRF, the kind of lights you can use become limited, especially in Singapore. You can only use them with incandescent, halogen and CFL dimmable bulbs that work with conventional dimmers. The problem is you cannot use them with most florescent tubes or CF lighting that require a ballast to turn them on. The majority of Singapore homes use them! You can pick a LightwaveRF device and study the specifications carefully.
After pointing out this huge misleading statement of no neutral wires required, I’d still recommend some readers to use LightwaveRF if they,
- Are unable to rewire their place
- Willing to use dimmable lights for the entire house
- Want no frills, basic and slightly lower cost home automation solution
- Do not need to know if their light is still on when they are away
- Are lazy to get out of bed and just want remote control lights
- Not geeky (I believe geeks love the 2 way communication)
To me, LightwaveRF is just like Z-Wave but comes with nicer switches (actually dimmers) and one-way communication at a lower cost. In Singapore you need not worry about LightwaveRF range unless you are staying in huge landed property. To close off, the claim about no neutral required is damn misleading.
Sources : Vesternet