I’m sure I was one of the first people to have central heating controlled by mobile. It was simple -on or off-, buggy -due to an issue in the Linux USB serial driver- and was probably used in anger no more than a handful of times.
Fast-forward almost ten years and I’m getting increasingly annoyed with the fact that whenever I turn the heating on I’m heating the whole house, starting with the room I’m not in. When we’re cold we move the mobile thermostat to a window ledge, and when we’re warm we hit the off button. Most of the time we can’t seem to find the thermostat controller at all, which makes for some more last minute fun when we leave the house for a weekend.
The company I work for is looking at integrating some smart thermostats, so I’ve been considering advice from some of our UK partners who are recommending Tado and Netamo. For my house with 3 bedrooms, front room, dining room and a “music” room, all with varying levels of insulation, it makes no sense to buy just a thermostat so Hive and the likes are out. Only a properly zoned system will do here.
Netamo? Tado? Evohome?
Netamo don’t do thermostatic valves yet so I rule them out.
The other system I considered was Tado which looks really nice, but the technical detail I needed was not clear and I wanted to make sure I also had electric underfloor heating support.
I decide to buy Honeywell’s Evohome system as at least I understand the solution. Again Evohome don’t excel in selling their solution on the website, but at least they support my key use-case: control heat to individual rooms and don’t run the boiler when it’s not needed.
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Let’s spend some money
Credit card in hand, ready to order. The first mini-minefield is the controller. There is an older version which requires an additional device to connect it to the Internet and some shops still retail it. As long as you buy the “Wifi” marked controller it seems all will be good. Reading some blogs, I find that the radiator valves come in “horizontal” and “vertical” versions – but this seems to be complete nonsense (although it is true for Tado valves).
So I end up buying:
- one “Honeywell ATP921R3100 Wifi enabled Evohome Controller”
- one “BDR91 Relay”
- and two “Honeywell HR924UK pack of TRV Heads (4 heads)”.
A bit of shopping around can easily save you GBP100 or so.
The postman always knocks twice
My supplier doesn’t use any tracked delivery unless you pay for it and I just choose the free second class post option. The parcel arrives two days after I order it, just before Christmas.
The Controller arrives with manuals in several languages, and the guide is simple enough. It comes with two rechargeable batteries and an adapter with UK and EU plugs plus a stand. I actually want to wall mount but I think I need to buy a separate part for that.
The thermostatic valve heads come in a box of 4 units, with batteries and adapters for different types of radiator valve. Very little documentation is included, as installation and configuration is all covered in the controller manual.
Installation
To install a thermostat a little electric work is always required, and my boiler uses the “N Ln Ls” type of 230V thermostat switching. This is easily supported by the relay box using a three-core cable from the boiler to the relay box and a bridge from Ln to the relay. If in doubt, hire an electrician.
Most of my radiator valve don’t need any adapters, I just unlock the base of the heads and screw them onto the valves as per the instructions. The Evohome heads can then be pushed on and locked in place. I do this after I have inserted the batteries and paired them with the controller.
Pairing the relay box with the controller is pretty simple once you know that you can put the controller into installer mode by keeping the “settings” button pressed for 3 seconds.
To put the relay box into pairing mode, keep the button (there is only one) pressed for 5 seconds, then press the green “bind” button on the controller. It can be un-bound by keeping the button pressed for 15 seconds. There is no simple way to test if the relay box and boiler now work as required, but it becomes pretty apparent when you turn up a radiator and the boiler doesn’t fire.
In our house each room has one or two radiators, so I configure each room is one zone. From the installer mode for each room create a zone, add a thermostat and follow the pairing instructions. The heads are a bit rubbish, as keeping the button pressed to pair them sometimes puts them into the pairing menu, and sometimes puts you into the valve configuration menu. You have to press the button once more to actually put them into pairing mode. Overall the process is simple but it’s not 100%. The controller then tries to confuse you by asking you to choose which temperature sensor you want, obviously you want to choose the head’s own sensor.
I find some Danfoss radiator valves which are not supported by the adapters in the box, and for those I purchase additional adaptors directly from Honeywell.
Testing
So it’s time to test. You can either turn the thermostat head on the radiator to increase the temperature or press the zone in the controller and override the scheduled temperature. If a zone needs heating you should hear the valve open, and shortly after the boiler should start. Since the thermostats only communicate every 4 minutes or so things may take a short time to happen.
Programming a schedule is straightforward and you can use a zone as a template for other days and zones. Use copy to set up the other zones and days.
Internet Connected
Connecting the Evohome system to your Wifi is easy. The surprising thing I found is that the controller doesn’t use NTP to set its time, so you have to do that manually. I also find that the controller does not support daylight saving. Running a TCP scan against the controller reveals no open ports.
To allow any form of mobile device control you need an account at Evohome and you need to register your controller with Evohome. To do this you must enter your address and postcode, an email address and password. There is no federated login option such as Google or Facebook. You then add your installation by entering two codes you can take from the Wifi setup page of your controller.
Downloading the app on your mobile phone or tablet is easy and you connect it to your Evohome controller by logging in with your registered email address and password. Why is the app not just called “Evohome” or something you can actually find without reading the manual? Only the Honeywell marketing department can answer that.
First Impression
For the first time our back room is warm. This is probably because the system is not trying to heat every room in the house at the same time. The house seems to be very evenly heated if we set all rooms to the same temperature, so this is definitely an improvement. If and how much money we’re saving I can’t say until next year.
The controller UI is quite clean and intuitive. My 12 year old daughter gets it immediately, of course. It will take us a few weeks to optimise the program but that’s to be expected. The pre-defined quick actions are useful for operations that affect the whole house such as switch off, set to 15 degrees, or reduce all by 3 degrees. These can be customised as well.
Originally I wrote: “The App UI is different, and seems to have had a little less thought but seems to support all the operations the controller has.”. But that is far to kind. The Honeywell App is useless and the developers should be shot. Most companies sell these solutions by first and foremost showing off a beautifully crafted App. A company like Tado understands this.
This is compounded by the fact that the Evohome system does not have a local API. Everything you do with your phone must go to the cloud platform first. If your network (or Evohome’s service) is down the App doesn’t even work in your own house. Evohome is not alone in this insanity. Tado, Netatmo and others work the same way.
If you’re in a room and want it warmer you don’t need to find the controller or your phone/tablet, you can just twist the top of the radiator to override the programming. It will revert to the programmed temperature the next time the program hits a new setting.
One interesting feature is the “window open” detection which can be disabled per room. I went outside to feed the chickens and left the door open for a short while. The thermostat detected this and instead of trying to heat the room it set the target temperature to 5 degrees until it decided the door was closed again.
One minus was that when I took the controller to the bedroom without the power adapter, it started beeping in the middle of the night for no clear reason. It must have been a low battery warning but didn’t say anything on the screen. I banned it to the hallway and in the morning the battery was completely empty.
Conclusion
The good:
- The Evohome Wifi controller with boiler relay and radiator valves works well and is easy to install and use
- It’s a truly smart system with lots of little refinements to save you energy and make managing your home comfort easy
- It supports a very large number of devices including hot water and underfloor (electric) heating.
The bad-ish:
- I’d expect a network connected device to use NTP to set its time
- Binding valve heads is a bit hit and miss
The bad:
- There is no local API to manage the heating, so if your internet goes down or the Evohome site have an issue you will not be able to manage your system via the App.
- The account registration does not support Google/Facebook login so you have to invent and manage yet another (in)secure username and password
- At registration you MUST supply a postcode. I can’t imagine why Honeywell want this and surely nobody in their right mind is going to enter real information here.
- Although the controller has batteries, a battery life of less than a night is completely useless so this device needs to be attached to mains at all times.
- In this day and age I would expect a local API with some documentation to integrate the solution with other smart home systems.
- No support for daylight savings
- The App is just terrible. I expected that maybe the tablet app would be nicer, but that is just a scaled up version of the phone App.