Z-Wave vs Wifi


(malamoney) #1

It seems that many on here favor Z-Wave over Wifi. I was wondering the main reasons for that.

Is it because Z-Wave devices play nicer with SmartThings?
Is one the bigger issues with Wifi devices such as Wemo that support just isn’t really there yet? For Wifi-enabled devices that expose a public API, I would think it wouldn’t be too difficult to integrate with SmartThings or any other app. Although I have yet to look at what it takes to write code for SmartThings.

The reason I ask is because it seems a lot of the new (and coming soon) devices are going with Wifi. But perhaps I am wrong.

Anyway, just trying to get an handle on the majority’s dislike for Wifi devices. Or more so the reason Z-Wave is much much preferred.

While I agree that it quickly becomes annoying to have to grab your smart phone and open an app to control your smart devices, there seem to be some ways to mitigate that pain.

If I have a light controlled by a Z-Wave switch. If I want to turn it off, I can use my SmartThings app or just press the switch. If that light is instead connected to a Wemo switch, I can either use the switch or the Wemo app. Seems like the same actions. Is the issue that Wemo doesn’t play nicely with SmartThings and thus cannot be incorporated into a larger set of rules/actions?

Has anyone connected Hue bulbs (or any other smart bulbs) to a Z-Wave switch? Does that make any sense?

Thanks for reading my rant…


(Geko) #2

A simple answer is ‘power’. Many Z-Wave devices run for a year or more on a 3V battery. Not possible for WiFi yet. Also WiFi devices are generally more expensive because they require more memory and more expensive microcontroller chips. There’re other reasons, of course.


(Michel Labelle) #3

The real issue is reliability.

WiFi, while relatively easy to implement in any consumer product, just is not as reliable in a home automation scenario.

WiFi aka wireless TCP/IP is a great protocol for delivering messages and data, but it was never intended to “control” devices, especially over wireless. The big challenge for WiFi is it is point-to-point. That means your device talks to the router/ap, that device then uses the TCP/IP protocol to decide how to route / relay the message to a wired or other wireless device. The devices don’t talk to each other directly (at least on the radio side, only the IP side). That means if your AP is badly positioned in the house, you will have dead zones where the signal won’t reach. You also have to deal with wireless congestion (those cut outs on your streaming media).

Z-Wave however, was designed to “extend” it’s wireless footprint. I’m generalizing, but just about every hardwired device (light switch, outlet or similar) probably has a built in repeater function. That means that so long as you have one every 50-150 feet you could literally cover your house, garage and back deck/shed area on one “meshed” network. The frequency being used also penetrates (extends) much farther. The down side is that, it’s not designed for lots of data (i.e. streaming media, pictures etc).

Another key issue on reliability is that if you physically change that light switch to z-wave. Well it works just like the original light switch, hub or no-hub, internet or not… This is key for many of us that have a few ZigBee or WiFi devices on our network. They just are not as reliable as they are typically “plug in” devices. That makes them easy to move around quickly, but not so great on reliability and consistency. If you look up the GE bulb/TCP bulb examples you’ll see people struggling with reliability.

Lastly on reliability. As the other poster mentioned. Z-Wave is really easy on the batteries. The devices “wake and go back to sleep” as needed, allowing for longer battery life. Since they can use the repeater function of other z-wave devices, they consume less power for their radios (broadcast power). They also don’t need to negotiate and deal with congestion on the WiFi network. So in all a much more reliable, longer lasting device. I change my water sensor batteries once a year (same time as when I update my smoke detectors), but I’ve had one last over 18 months… Same for my door lock.

Going forward you will definitely see a mixture of z-wave, zigbee, Bluetooth LE (Low Energy) and yes WiFi devices on your hub.

The main reason, well the last 3 in that list require less technical expertise (i.e. they just plug in and can use the “UPNP discovery” protocols to be quickly added to the network). A light switch is beyond the comfort zone of most people to replace. Also z-wave, because it is proprietary is still relatively expensive for an equivalent device vs. the other items to build.

And finally… there is the big-bad-cloud. Z-wave device upgrades are not for the average joe. We are in a world where everyone expects new functionality and patches to just happen. Us older IT folks, are comfortable rolling up our sleeves and hacking the system to do what we want, but if you are an average person, and just want to plug that device in, well having the cloud automatically monitor, update and patch your devices is a bonus. But that means you are dependent on TCP/IP and some central cloud service provider. And the delivery mechanism of choice for TCP/IP these days is WiFi, since you get down to just a power cord in terms of device management.

So if you are in an apartment, or tend to move every few years, definitely go WiFi/Zigbee plug in. But if you are in a home and intend to be there for the next 10+ years… hands down go z-wave.


(malamoney) #4

Thanks for the in-depth response. I appreciate it. Can you explain what you mean by “Z-Wave device upgrades are not for the average joe”. Do Z-Wave devices often need to be upgraded? And if so, how does that happen? I am more of a software than a hardware kind of guy. I am comfortable however switching out an outlet or switch.

Thanks!


(Michel Labelle) #5

Re Z-wave upgrades. I’ve had one device firmware in a number of years. So basically rare-to-never. That one device was a controller and the tech support folks did everything remotely in my case.

Z-wave is relatively mature in that regard, so that’s another advantage I guess.


(Brandon) #6

The only thing I would add is that ZigBee shouldn’t really be “lumped in” with WiFi and is much more similar to Z-Wave then the description would indicate. It also “meshes” and has several advantages over Z-Wave, one of the major ones being is the network doesn’t require itself to be manually repaired on a regular basis. Any difficulty you read about a ZigBee device and SmartThings is more likely that the device doesn’t have tight integration just yet (see GE Link Bulb), and not a fault of the ZigBee protocol.

That being said I have 4 GE Link Bulbs that all work fine.


(Scott G) #7

I half agree with you Brandon. It’s very similar to zwave, but my issue with Zigbee is that it uses the overcrowded 2.4ghz spectrum. The average user is not going to want to manage their wifi, cordless phone, bluetooth, and zigbee channels in the 2.4ghz spectrum to manage interference. Too many wireless devices use that spectrum for my liking, and I’m pretty sure it does impact the performance of my devices already. That’s why I also dislike wifi for the connected home. I don’t think consumer routers are strong enough to start managing the number of devices and the potential interference with neighboring networks well enough.


(Brandon) #8

That’s an absolutely fair disadvantage. I personally don’t really qualify as your average consumer in the networking space (wired up house with business class router and AP) so I tend to not have to worry about things like interference and thus occasionally forget about them.


#9

I notice that a lot more wifi devices are out and cheaper than zwave devices. I’m thinking about switching to WIFI since my zwave devices are Unavailable. I’m not sure if it’s zwave or smartthings, but the process of trying to get this back on Zwave mesh is not fun and very time consuming. Part of the idea of smart house is energy savings, someone said wifi requires more juice. Can someone know the difference in power consumption between zwave and wifi switch? Some of these wifi devices are $22 compare to $39 zwave.


#10

Zwave range is also an issue You have to get a repeater just so you can get a switch to work.


#11

The following FAQ, particularly post five, should answer some of your questions (this is a clickable link). The FAQ IS old but still accurate.

To answer your specific questions, Wi-Fi devices typically use 4 to 10 times as much energy as zigbee, and about 5 to 8 times as much as Zwave. But it depends on the specific models, some manufacturers worry a lot more about power efficiency than others.

With regard to repeaters, there are two answers to that. First of all the whole point is that mesh devices repeat for each other. If you have a Z wave light switch in the living room and a zwave light switch in the kitchen, they can repeat for each other. You don’t have to buy special repeating devices. Most people will not have to buy extra Devices just to repeat. See the following FAQ, start with post 11, then go back up to the top and read the whole thread.

The second answer is that because it’s a 360° signal and zwave plus will cover typically around 65 to 70 feet in standard US residential construction, for many homes that’s already enough to cover a home. Certainly an apartment.

So it all comes down to exactly which devices you have and where you are going to place them. There’s no question that Wi-Fi has much better range than zwave, it’s just that for home automation, Just the devices themselves are usually enough to create a mesh that will cover a standard house. See the following FAQ:

From my own point of view, the number one issue with Wi-Fi is that power consumption is too high for battery powered sensors, and I really like battery powered sensors for home automation. :sunglasses: Both motion sensors and contact sensors can give you a lot of flexibility In adding Home automation. For that matter, there are only a couple of Wi-Fi – enabled smart locks because of the battery usage issue, and most of them get terrible reviews. I would always choose another protocol for a door lock.

And of course the practical limit on the total number of Wi-Fi devices you can have is low enough that many people trying to automate an entire household run into it. I can fix the range issue with mesh very easily, but I can’t fix the router issue without upgrading to commercial grade systems which are way more expensive than the amount I’d save by using WiFi switches.

But each person has to make their own decisions with regard to which protocol or protocols will work best in their own home. If you find Wi-Fi switches that you are happy with, you don’t care about the energy usage differential, and that’s the only Device class you need and you don’t max out your router slots, go for it. :sunglasses: