The answer to these questions may have been answered in several articles online, we'll try to answer this question in Singapore context. Z-Wave and Zigbee has been around in many years and will still continue to dominate for many years.
It used to be that we only have to choose between Z-Wave or Zigbee when deciding on the smart home hub. As multi protocol hub such as SmartThings and Homey appeared, it eliminated that need to make that choice. In recent years, there've been increasing number of wifi based smart home devices touting the benefit of not requiring a hub. Almost every new smart home devices work with Google Assistant or Amazon Alexa, over wifi. Even devices such as smart locks or even motorised blinds would have a wifi bridge and work with the various voice assistants. So should we simply throw Z-Wave and Zigbee out totally? Here's the considerations that you have to make.
How many Apps would you like to use?
You have an app for Philip Hue, another for Ambi Climate, another for your Samsung smart lock, and not forgetting another app to control your Somfy blinds. It is true that you can voice control all of them with your Google Home but you still have to go to each of them to set your schedules and most of the time they don't talk to each other through Google Home. There be some wifi devices that cover a few aspects such as lighting and IR blaster for AC within 1 single app. But what if you like to control that new Dyson fan in the bedroom?
A hub based solution allows you to control, create scenes or schedule across different devices on Z-Wave/Zigbee/wifi devices on a single app. However, if you can live with multiple apps, only have a few aspect to manage or only use voice control, you can consider going for wifi based solution.
Wifi is too congested in Singapore
Especially for Singapore where you use your mobile to scan for wifi hotspot, you'd probably see at least 20 SSID in the list. Some areas of your home might encounter interference by your neighbour's wifi signal causing some wifi devices to not work properly there. You can probably put in a powerful UniFi access point to dwarf your neighbour wifi signal or they can do the same in return. Zigbee might encounter the same issue as it is running on 2.4Ghz. You will not get the same interference with Z-Wave because it is running on a sub 1Ghz band with better wall penetration (lower frequency passes through wall better).
Can you accept that automations doesn't run when you lose your internet connection?
Most schedules and scenes on wifi smart home devices are stored in a cloud. When internet is cut or wifi is down, all your scenes and automation will fail. Then again, internet services in Singapore are generally stable, even if there is downtime, it shouldn't last even a day unless there is major destruction of internet infrastructure. If the fault lies in your own router, you'd probably run out to get one in your heartland mall immediately. The sad truth is, wifi is like water to most of us these days.
There is less interoperability/integration on Wifi
Wifi smart devices usually just works with Google Home and Alexa at most. They do not actually work across different brands. For example, a wifi touch switch cannot be programmed to turn off everything (other Wifi smart devices in the house). You cannot make a motion sensor from Philip Hue shut down other smart devices in the house when it detects no motion for more than and hour.
In a hub based smart home, take Homey for example, you program a Z-Wave switch at your entrance to turn off all other smart devices in your house including stopping the music playing on your Sonos. Of course, some wifi based smart devices allow you to use IFTTT to talk to devices from another manufacturer.
Battery powered Wifi sensors/devices is a joke
Wifi and battery can not be used in the same sentence except for this one. That is why for smart locks, even if there is a wifi option, it always come in the form of a wifi bridge. The lock speaks bluetooth to the wifi bridge. There are some motion or door sensors that runs on wifi but by the time they wake up from event, connects to wifi to report motion or opening of doors, 5-7 secs would have passed.
Your Z-Wave/Zigbee device can still be reused even when the company is gone
Wifi devices are mostly could dependent. In the event that the cloud services is gone with the company, you are likely to be left in the wild. For Z-Wave/Zigbee devices, your concern should be the hub as it presents as a single point of failure but you are likely to be able to use it with another latest greatest Z-Wave/Zigbee hub.
It is easier to start your smart home on wifi
As wifi chip are generally cheaper than Z-Wave and Zigbee chip, the prices for Wifi devices will be lower. As such, if you just like to try out smart home, wifi is definitely the way to go due to the lower cost and you do not need to invest in a hub just to try things out.
If you are a home owner who simply want something basic and affordable to control your home with app and voice control without much sophistication. Wifi will be a good choice.
So how?
Our advice is, go for wifi devices if you like something basic such as lighting and aircon mobile and voice control. You simply have to make sure your wifi is strong with good coverage. It is simpler to manage for the less tech savvy.
Go for hub based Z-Wave/Zigbee solution such as Homey if you like to future proof your home as it provide more integrations for future expansion, less chances of signal interference. Geeks and more tech savvy home owners would appreciate this solution more.
Automate Asia Team
This article is part of Series of articles to start your smart home journey, the smart Singaporean story