I have an old home and therefore have a very simple setup which is Heat only via steam radiators. For the past couple of years I've been enviously looking at the Nest and Honeywell Wi-Fi Smart thermostats, but have never been able to bring myself to spend $300+ to get a C (common) wire installed (the high cost comes from quotes from "certified" Nest installers). Couple that with the cost of the thermostat itself and it becomes a very expensive solution that would only be used for a fraction of the full year. The envy only got worse after getting Smartthings working with my lights because I yearned to extend my home automation capabilities. Finally, I couldn't take it and had convinced myself to settle on getting one of those bland, ugly zwave thermostats, BUT thankfully somehow...someway... the grace of the tech gods guided my browser to the ZEN and my whole being expelled a big sigh of relief! ZEN is more expensive than those ugly cheap z-wave thermostats but I bought an Amazon Warehouse open box unit which came to me with no scratches or blemishes of any kind and was "like new" for a very nice discounted price. It is a very simple and straightforward unit which gave me pause but with the integration to Smartthings and it's slick modern design, gives me everything I need. As it pertains to my Smartthings set up, I have Smartthings routines to turn down the heat at a certain time at night, to turn down the heat when i leave the house, and turn on the heat in the early evening so that the house is warm when I get home. I'm also able to remotely manually check and override the temperature setting in the Smartthings app. The last bonus that makes this such a great product for me is that with my Amazon Echo, I can tell Alexa to set the thermostat to a particular temperature and she responds to me with a gracious confirmation as the ZEN thermostat complies.

Works. But sometimes the thermostat does not properly attach to the wall plate because the attachment is facilitated by markets instead of a proper click to secure bracket. So every now and then I will go half a day without AC just because the thermostat decides it is not seated properly. I paired it with smart things and it worked ok until no matter what I did smart things started setting the thermostat to lower than my current setting in their device settings / and custom programs. I checked and double checked everything. My cooling temperature as 70, yet something kept setting the thermostat to 69 then to 68. It was like it was possessed. Currently it is off of the smart things and keeping the temperature normal so it is not the thermostat. I had to make sure it wasn't the thermostat. Aside from that it works beautifully. It seems to have a different temperature measurement than my previous thermostat. In the previous thermostat I was comfortable at 70. This one if I set it to 69 I freeze, if I set it to 70 it's warm -- it is VERY strange. But I can live with it. I am looking forward to redoing the smart things connection so that when I come back to the apartment it sets the thermostat lower and when I leave it adjusts it up. It's a good idea but may need a version 2.0. And why is this box this expensive?? This thermostat has no programming in it, it should be 100 dollars or less.

Where do I start with this thing? Let's see: The "display" if you can call it that is nothing more than a matrix of LEDs that simulate letters and numbers. There's no LCD screen or even a familiar LED (iPad, TV, etc) screen. When I first put in the batteries I thought something was wrong. The interface is *terrible*. It's nearly impossible to distinguish an "8" from a "B". The LEDs in the matrix are so far apart that it's actually easier to read the display at six feet or more rather than close up. Think Star Trek blinking lights at Sulu's console. Too far apart. Lag: Wow....when I set a temperature, turn on heat/AC or turn on the fan from a smart device I expect it to respond within a second or two. It took a full 27 seconds before the fan would turn on. Temperature settings: Who thought that setting a 79.4 or 68.7 degrees is a smart idea? MAYBE setting a half a degree makes sense at the zero and point-5 range. Instructions: The web site that helps you determine how to set up the wiring doesn't work (at least for me) in Chrome. I kept getting "We need more information. Please email a picture of your wiring....". I had to use Internet Explorer to get past the first step. The "touch" screen. Another wow. There's no indication whatsoever on where or how to touch this thing. Swipe? Naw.... The other difficulty I had was in setting the proper code for my furnace. I thought I could push and hold on the screen and it would eventually "spin fast" to bypass the 100 codes I wasn't interested in. Unfortunately, it would scroll through about 30 codes before stopping and making me release my finger and press-and-hold again.....only to be faced with the same unwanted pausing/stopping. Sometimes simple is better. My current wireless thermostat (now abandoned by Duke energy) isn't great but it's world's ahead of this thing. This thing is NOT simple. It's a terrible and difficult interface to navigate. I would have gladly spent $50 more for a LCD touch screen instead of that junk LED matrix. It's reminiscent of "Future World." Back in the box and returned for refund.

I purchased the ZEN Thermostat to integrate into my SmartThings network to manage my heating system after already having a ZWave Honeywell thermostat already installed with my A/C system six months prior. I did a lot of research within the SmartThings community and on Amazon and was confident the ZEN would deliver; but I was pleasantly surprised by not only the design but the ease of installation. There is no question that if you're considering both the Honeywell and ZEN, don't hesitate to purchase the ZEN. First off, the out-of-box experience is superb with a link to their online site to help guide you through the installation process, the site is mobile-friendly so you can easily use their online guide from your mobile phone which is handy installing the wiring. They have lots of visual guides within the online guide and they make it impossible to mess up regardless of your skill level. Plus, you can take a picture of the old thermostat wiring while you have your phone in your hand to refer back to. From identifying what type of HVAC system you have to wiring the thermostat, it was easy and surprisingly quick. I spent more time patching and painting the wall behind and around the new ZEN beauty than the installation itself. It paired immediately with the SmartThings hub and I was creating rules to manage the ZEN in no time. Now, the real reason you buy the ZEN is the design and it is even better looking in person than on Amazon or their own website (I bought the white one). The ZEN is slim and looks great on the wall, the LED lighting creates a really nice and intuitive interface; absolutely no learning curve whatsoever. If you have a SmartThings installation, the ZEN thermostat is a "no brainer" purchase. Finally, don't worry about the Nest. You don't need the complication because your ST hub manages ZEN and the LED interface it much more elegant than the Nest...save your money.

I was super excited to get this product but it has me second guessing my purchase. My product appeared to be refurbished when I got it. It had a slight chip in the screen and didn't even have a protective plastic on the screen. It is harshly scratched up and has lots of glue on it. I will be returning it for a new one. There is simple instructions that come with it but they are very basic and don't tell you what you need to know to correctly install. Unless I am missing something, I couldn't find this in the instructions, you have to visit http://zenthermostat.com/install/install.php . This website was more than helpful. You tell it what wires you have and it diagrammed it out for you. That made it super easy. The mounting hardware it came with seemed simple enough but it turns out the wall anchors are pointless!! There is no head to them at all and one of mine went right through the wall. Upon trying to repair it the other one went through too. I used new anchors and screws and now my unit rocks up and down over the screw heads because the heads are too big. Super annoying! Programming to my Smartthings Hub 2.0 was super easy. I tested it from the app and it works as expected. Simple operation on using the unit takes some training and not as easy as you would have hoped. It drove my girlfriend nuts. She hates it. The LED lights make the screen a little difficult to read the words because the illuminate the plate. You can increase and decrease the brightness but it is not very clear and easy to read as you would think it should be. Right now we have the air off. To turn on the AC, you have to scroll over through the menu, select Cool and then you can adjust temperature up and down. It is difficult at first to understand the operation but once you do it a couple of times it makes since. Just don't go letting a guest play with the thing. They will never figure it out. Like I said I will go ahead and order a new one that isn't scratched up and try it out for a couple weeks before deciding if I really like it and want to return it. I may post a later review about the usage. Updated Review After using it for a couple of weeks the usability of this unit isn't that bad. Once you get it you get it. My girlfriend can use it like a pro now. I got a new unit that isn't all gummed up and it was super easy to setup the second time around since I knew all the work arounds. The product works perfect with SmartThings hub 2.0. No issues what so ever. I recommend this product just know the wall anchors and instructions that came in the box aren't worth a darn. The good news is you can get different anchors and online instructions from the manufacture site are great. Also note they give you stickers to label your wires. None of mine stuck. They all fell off. I did upgrade from a 2 start to 3 star because it looks good and it does work as expected.

UPDATE 03/2018 Thermostat has been working flawlessly so far. The unit doesn't drop off the network anymore, maybe a fix from vera or zen. Response time is very fast now. Scenes fire up successfully everytime. Also, I have Alexa commands now through Vera so giving it commands to adjust temperature works wonderfully. I seldom check the ZEN display screen now. I do hope they release a version in future for always-on display. Unit is still on original batteries after almost a year. Review upgraded from 4 to 5 stars. Original review below I bought this to pair with VeraPlus, although ZEN doesn't specify if it works with VERA. But since both devices support ZIGBEE I bought it to try out and hopefully this review will help someone with a Vera unit. Installation is pretty straight forward. Their online setup walk-through makes setup a breeze. Just make sure to enter in the code for your heater/ac setup. I have a basic gas wall heater and I believe my code was 10b or 10a or something. The website/manual will tell you the code for each type of setup. Pairing was a little troublesome as ZEN thermostat is not a listed support device in VERA menu. I tried pairing as a generic zigbee device but it did not work. I then tried pairing as one of the listed thermostats one-by-one and I believe it connected when I selected one of the Centralite thermostat on menu. Once connected I renamed the thermostat. The device options shows temperature, Heat/Cool/Off/Auto functions, and setting temperature buttons etc. I setup a scene for the thermostat to turn on at a specific time and it did. It takes a minute or two for the heater to turn on though. I've read others complain about this as well which I'm hoping will be fixed by ZEN. I've had it for few weeks and the device connection was lost for few days and regained connection again. Good thing I can adjust temperature through the device display. It should be noted that to do any kind of programming/scheduling, you'll need some sort of hub since you cannot do it through just the device itself. It's summer here now so I am not really using the thermostat to do anything yet but will update when winter rolls around. The only other suggestion would be to have an ALWAYS ON display (Even if it has to be dim to preserve battery). Tapping every time to see the current temp gets a little annoying. The manual says that it is an option on some devices but apparently not this device. Overall happy with it. Hope Vera gets standard support for this device though.

The ZEN Thermostat is a good basic ZigBee thermostat. I say "basic" because it really relies on your existing ZigBee home automation system (I'm using SmartThings, but it also works with Securifi Almond and a few others) to do most of the "smart" work. Without a home automation system, all you have is an expensive, non-smart thermostat, though I should note that it will still work perfectly fine as such. However, your home automation system will add the ability to control the thermostat through that system. For SmartThings, this means I can control the temperature with the SmartThings app while I'm at home or while I'm away. I can also use my Amazon Echo to set thermostat's setpoint via Alexa. Finally, I can use other SmartThings features to "program" my thermostat to do what I want--for example, turn the heat down when SmartThings hasn't detected motion in my home for a certain period of time. The exact capabilities you'll be able to get depend on the capabilities of your home automation system, but with SmartThings is able to do about anything I'd want the thermostat to do, and other systems should provide similar functionality. Back to the thermostat itself, I found it easy to install. Just make sure you mount it right-side up (there's an "up" arrow on the left side of the backplate.) There are printed instructions, but their website is much easier to follow because it will customize the instructions for your particular setup. Unlike many other smart thermostats, you do not need a C-wire for this one, but it can connect to one if you do. It requires four AA batteries (included) regardless. My main complaint is that the display is a bit hard to read. It consist of widely spaced dots, which are mostly readable when you're looking at the temperature or trying to set it (despite some bleedthrough, at least in the white version I bought), but is somewhat difficult to read when you're trying to do the initial configuration (e.g., "8" and "B" look similar). Setting the temperature on the thermostat itself isn't intuitive for everyone, either. By default, the display is off. If you touch it once, it will display the current room temperature. To set the setpoint, you need to touch it again, then press the up/down arrows that appear, then press the center (setpoint temperature) again to save. If you want to change mode (heat/cool/off) or fan (on/auto) settings, you need to keep tapping the center. If you have guests or others who might need to control your thermostat, you'll need to explain this. All things considered, this is a good thermostat (though your home automation system will determine how "smart" it is for you) that looks nice and is much better priced than most other "smart" thermostats. Minor quibbles aside, I like this thermostat, think it is good value for the money, and would recommend it to anyone with an existing home automation system looking to upgrade their thermostat.

Disappointed with the led display on the white zen thermostat. There is significant light bleed through around the numbers. This makes it very difficult to read the display. In my opinion the leds should also be closer together and include information such as the current time and outside temperature for example. The thermostat is mostly hallow and could be at least 1/4" thinner to give it a lower profile. Not worth the high price tag. UPDATE 14 December 2016 Vanessa from Zen mailed a replacement thermostat. After receiving the replacement thermostat, I held it up to the one ordered from Amazon and it had the same light bleed through issue. Zen should invest more in the research and development of their product and not be complacent. What was considered nice and cutting edge in 2013 is no longer the case in 2018! 1. Fix the light bleed through issue 2. Make this relatively hallow product thinner so it has a lower profile.

There is a lot to like about the Zen Thermostat, though it fills a very specific role and buyers should make sure they know what they want. If you use a home autmation system (I use Smartthings), the Zen Thermostat looks good and has all the options you need and no uneccessary extras. A major bonus for many will be that the Zen Thermostat does not require a c-wire. I think Zen is a great option for Smartthings, and I like the product where it has worked for me (clarified below). Importantly, if you don't use Smartthings (or something like it), the Zen Thermostat has very few features on its own and you will be disappointed. This is just something to know... I still would recommend the product and would have given the Zen Thermostat 5 stars for its fit with Smartthings and aesthetic, but I unfortunately had mixed success installing. I bought four Zen Thermostats for four PTAC units I have in my apartment. Two of the PTACs are one model and two are different. For some reason the Zen Thermostat worked perfectly on one model, and didn't work at all on the other. Support emailed me back withing 24 hours, but was unable to help and suggested there was a problem with my system. Both a Honeywell and Ecobee Thermostat worked fine, so my read is that there must be some flaw in the Zen design that made it fail with those particular PTACs. Their suggestion that it was my system and not their product could have led to unneccessary spending on a professional installer. For what it's worth, I could argue the Ecobee Smart Si is a better value as it is cheaper and offers many more options for people that don't intend to use the Thermostat with a home automation system, but you do need a c-wire.

My Zen is one of those rare products that works so well I rarely even think about it at all. In winter Zen takes care of the heating by itself for the most part, and in summer it's the nicest looking thermometer I've owned. I was an Indiegogo backer so have it paired with Smartthings home automation hub. Although the Smartthings software isn't as simple as they pretend it is, once I'd set up the schedule and events to turn my heating on and off it has just worked quietly ever since. Its best feature is the peace of mind it provides. The heating comes on in the morning and evening on a schedule, but if both mine and my wife's phones are outside the house, then it turns off again, saving us money. It turns off on a schedule too, but will stay on for longer than normal if it's really cold. And finally, we can change the setpoint or turn it on or off from our phones too, whether or not we're at home. One of my main quibbles in adding 'smart' devices to my house is that for the most part a dumb house works pretty well anyway. And when your 'smart' gadgets go wrong, the consequences or frustration can negate all the benefits they were meant to provide. Fortunately, Zen isn't like that - it's not so much 'smart' as just 'sensible'. If the home automation hub stops working your HVAC falls back to the manual control it started with, so there's no danger of being unable to control your system at all. So overall? Beautiful design, sensible software, and an interface everyone can use. Top marks!