2-bed flat, recently refurbed to be well insulated. Occupancy patterns are a bit irregular because some days I work from home, and I also have a guest room which is occupied some nights and not others.

At the moment I have combi boiler on programmable timer, and TRVs in each room but I want something more flexible and which is easier to control on a day-to-day basis. Also ideally I'd like it to be possible to control the temperature in the guest room from within the room without affecting the rest of the flat.

I only need 3 or 4 zones.

Options I've investigated so far -

Honeywell Evohome
Looks like nice UI and good level of control and can do what I want. Expensive though. Prob around £400 for my needs.

Heat Genius
Looks like it can do what the Evohome does, but with some additional options like PIR sensors for automatic control based on occupancy, and the ability to record data over time. Seems to be even more expensive than the Evohom though, £400+

Homematic
This looks like it could probably do what I want (plus quite a lot more as optional add ons in the future) but is a German system without much info in English and looks like it could be a bit involved to do the setup. UI doesn't look terribly user-friendly. A bit cheaper than Evohome or Heat Genius but not much. Maybe £370.

eQ-3 MAX
This is much cheaper than the others (£150ish) and looks like it can do what I want but it doesn't seem to have any control over the boiler itself - basically just assumes that the boiler is already on. This seems a major drawback to me. There are some diagrams here:

http://ecohousecomfort.com/termic-zone/max-range.html

which suggest how to deal with this but neither seems satisfactory. Either you have the boiler on a wall switch which is turned on/off by a centrally located stat. But this stat doesn't seem to communicate with the others so as far as I can see you will end up either with the room stats calling for heat and not getting it because central stat has shut boiler down, or central stat has switched boiler on but none of the room stats want any heat.

The other option seems to rely on the boiler's own protection circuit switching it off if all the room valves are closed and the return flow is coming back hot. But won't this just leave the boiler endlessly switching on and off, when there's no demand form the room stats? That doesn't sound like it would be very good for the boiler.


Does anyone have any experience of any of these systems, or suggestions for others to look at?

And is my concern about the endlessly cycling boiler with the MAX system a reasonable one, or isn't it really an issue?

Yes, gas combi boiler.

Conventional radiators, no UFH or anything complicated.

These systems sound expensive, have you considered the pay back period.

A fourth and possibly cheapest option would be to go down the user intervention route. Turn the TRV to zero in the guest bedroom when not in use and use the on/off switch, or programme in the boiler to match your lifestyle, as appropriate.

Posted By: lineweightSo mainly what I want is more fine-grained control over different parts of the flat, for comfort reasons as much as energy-saving. And my requirements are perhaps not the norm for a 2 bed flat.

Have a look at
http://www.honeywelluk.com/products/Valves/Thermostatic-Radiator-Valve/Electronic-TRVs/evohome-zoning

Posted By: lineweight
I do find it surprising that there's not really a simple way of getting individual TRVs to talk independently to the main boiler switch. It doesn't seem like it ought to be a major technical difficulty.

These are mainly aimed at the continental market, where district heating systems are common, i.e. no boiler. Large thermal stores are also fairly common and there is no direct boiler control for them either.

They are excessively expensive, but the retrofit market must be pretty small - unless you can get the sort of publicity that Nest got.

There are ways of getting the eQ-3 system to control a boiler but they involve another computer and fiddling about with fairly obscure software. See the Domotica forums for ideas, http://www.domoticaforum.eu/. Specifically the FS20, FHT, ESA and ELV sub forum and the Homeseer scripts sub forum. I tried to use the Homeseer HS3 script with my eQ-3 system, but it crashed the cube and lost all the settings which was rather tedious. As pump control isn't very important in my system I've given up on it at the moment.

Posted By: TriassicThese systems sound expensive, have you considered the pay back period.

A fourth and possibly cheapest option would be to go down the user intervention route. Turn the TRV to zero in the guest bedroom when not in use and use the on/off switch, or programme in the boiler to match your lifestyle, as appropriate.

I did this for a while. It gets old quickly, and, again, is worse in a larger home.

lineweight, you might find the Automated Home forums useful.

We have the house heating split over 3 zones with each zone having its own programmable room stat and zone valve. Each stat controls its own zone valve and if one or more zone valves are open the boiler fires up.

Unless you've got access to your CH pipework it might be quite disruptive to replumb to separate the guest room pipework from the rest of the flat??

Posted By: gravelldHG is z wave in case you're interested.

Phil these systems are called 'soft zoned' where really it's the radiator that's zoned, not pipework. This makes them easier to retrofit.

Yes, i have just been reading quite a useful thread about it here:

http://www.automatedhome.co.uk/vbulletin/showthread.php?3789-Heat-Genius

Ah yes LightwaveRF was taking a long time to release when I wanted to install. Iirc they launched without interlock so I gave up waiting. Worth looking into.

ps if you post as text the URL is converted to a link.

That's exactly the same thread I remember reading as I was about to install. It's over a year old, they might've improved since...

Meanwhile I've also come across this system. It seems to include a boiler switch but information about it is frustratingly sparse -

http://www.guardianstore.co.uk/blog/introducing-istabai-smart-heating/

A bit more on the "Istabai" system - spoke to them on the phone.

http://istabai.com/

It's an Irish company, seem only to have been going for a year or so.
[correction - the product actually seems to be Latvian, but the guardianstore.co.uk site links through to an Irish company]

They don't have loads of info online at the moment because they have mainly been selling through installers, who they train up. They may have more up in the next couple of months though, so might become a bit more feasible as a DIY install.

Their system does have boiler interlock, controlled on a zone-by-zone basis, so similar to Heat Genius or Evohome. The main difference from those systems is that there are pretty much no manual controls - everything controlled by app or web interface.

You need a wireless radiator valve regulator plus temperature sensor in each zone. The temp sensor can link to several rad valves within that same zone. There are also motion sensors (not yet avavilable though).

Cost-wise it looks slightly less expensive than Heat Genius - boiler switch £50 plus base station £100 (so £150 compared to HG £250 for hub kit). But then the valves (£75) and temp sensors (£45) similar cost to HG.

Or you can get a 2-zone kit for £360 (HG equivalent would be £480 inc shipping)
Or 3-zone kit for £475 (HG equivalent would be £585 inc shipping)

Posted By: gravelld

Posted By: lineweight
However, if you also have a wall stat in that zone, it can log the "real" room temperature and it can also be used to control that zone manually.

This is all what it comes down to really. What you're suggesting isn't really a "standard" HG setup (I've tried both ways). You need the room sensors.

Yes.

It's looking like I'm probably going to go with Evohome on cost grounds. Base kit for around £200 (or £150 if not bothered about wifi connectivity). Rad valves £55 each and talk directly with controller. Option to add wall-mounted sensor if you want.

Doesn't offer the motion sensing or data logging capabilities, both of which woudl be nice but it doesn't seem worth paying a couple extra hundred quid for. I could probably set up an independent temp logging system for less than that.

Posted By: lineweightThe downside of this however is I then don't really have any control over the temperature in the other rooms. For example, it might make sense to have the radiator in the (not insulated) bathroom go on in the morning before people get up, but that doesn't work if the firing of the boiler is controlled by the main stat in the guest room. And again, easy for them to leave the temp turned up when they go out for the day.

I'm not a heating engineer, but as an electrician I don't see why you shouldn't wire two room stats in parallel (provided all wiring regulations are followed, obvs.)

Then the pump would start if either stat indicated a demand for heat. Your guest's actions would never deprive the rest of the house of heat.

The actual temperature reached in each room would depend on the room stat setting and the TRV setting, whichever is lower. And though that sounds confusing, it's exactly the same as the typical British system where if you want heat, you have to check that both the room stat and the TRVs are set high enough.

Anyone tried this in practice?

By the way, I got a reply from LightwaveRF -

My question:
I am trying to find out whether your lightwaveRF TRVs, and/or room thermostats are interlocked with the boiler switch. In other words if I have a zoned system, and there is a call for heat from just one zone, can it turn the boiler on/off as necessary, or does the boiler have to be on all the time to allow the zones to call for heat individually?

Their answer:
For every zone you would need to install the thermostat/boiler switch combination (x1 Boiler x1 Home Thermostat per zone). The boiler switch does the actual switching of the relay while the thermostat does the timer control and temperature sensing. A combination of both would need to be installed at every zone location.
In regards to the TRVs, they can not be grouped and do not operate with the thermostat nor with the Boiler switch, they behave independently to control each radiator. In the future, there will be an update to the WiFiLink which will allow it to support a 'call for heat' feature.

So at some point in the future, their system might offer a cheaper alternative.