From time to time we’re asked about this little Swiss Army Knife of automation thermostats and how it works with WIFI and Zwave, and what happens if the various networks go down. So here’s a quick run down.
When used standalone, it controls its own schedule like any other thermostat. But you probably didn’t buy it for this.
When used as a WIFI device, it controls its schedule as updated from the internet portal. There is no ‘outside’ controller here. The programming is still stored on the thermostat. The (free) Internet portal allows remote changes to current temp or overall schedules and then downloads those schedules back to the thermostat.
When used with Zwave it is by design going to let the Zwave controller handle scheduling and doesn’t run any internal schedules to avoid confusion since you now would have 2 different controllers. This is common with Zwave thermostats.
But what if my Zwave network or controller goes down?
If the zwave network goes down it will simply stay at the last temperature. You can manually change it. When the Zwave network is restored, it will pick up the next change the controller sends to it.
Realistically with a thermostat you want to have it set to a moderate set back during the day or when you’re not around.. eg. a few degrees warmer or cooler to save energy. Much more than that and you will find it either takes too long, or takes too much energy to get back to your ‘comfort’ mode. This is general advice from a number of sources including some publications from the CDN government. Setting back a thermostat too far starts to defeat the purpose unless its used in a place unoccupied for days, weeks or months.
So based on this logic, if the zwave controller stops working the temperature will stay at the last set point which won’t be too far off and you can manually adjust it when you get home. If you aren’t messing with the network then it really shouldn’t go down other than due to a power failure (in which case your heating is off) or a major problem. We’ve sold a lot of zwave thermostats over the years and while we do find some people are concerned about it up front, in practice it has not been an issue.
Meanwhile it’s a great inexpensive way to take control of your heating and air conditioning!