Smart thermostats and timers

[Steve Wegerle]

Hi guys,

Hoping I can get some input on a subject related to an extension I am currently having done. My set up is that I have central heating in the majority of the house but as part of my ground floor extension, I am having a water pipe underfloor heating system fitted.

I have a megaflow tank (picture attached) and a potterton boiler (picture attached). My underfloor heating is a grundfos 2 zone manifold with Hetta aluminium pipes.

My question is on timers and thermostats. What exactly do I need? I have purchased 3 Google Nest E thermostats (Presuming I can use one for the main house central heating and water with the other two each controlling the underfloor heating zones). Is this sufficient for me to control my heating and hot water timers etc or do I need a dedicated timer? The reason I ask is because my builder has gone ahead and fitted a timer already (a "Lifestyle LP522") but he's confessed he doesn't really know much about smart thermostats and what functions they can/cant replace.

I do want to go the smart thermostat route, I understand the nest learning thermostat 3 can do more than the Nest E, I'd be happy to buy one of these if it removes the need to have a separate timer.

Appreciate any guidance!

Thanks,

Steve

 

[muggles]

You'd be much better off returning all your Nests and buying a proper system designed to work with multiple zones and underfloor heating. Some UFH systems require floor sensors to be connected, to prevent the floor getting too hot, and if that's the case with yours you'll need to buy a smart stat system that can accept a floor sensor. Heatmiser Neo is a good option in that case, and in any case if all you want is a system to control your heating.

Other than that, the Salus Smart Home range is very good and very reasonably priced, with the option of adding in extra things like smart plugs, immersion heater timers, smoke detectors etc etc.

 

[Steve Wegerle]

Thanks for the comment. I just wanted to run all of my heating and hot water off a single app and I understood the nest ecosystem to be one of the best along with Hive systems.

 

[DP]

Evohome all day

 

[muggles]

Nest is best suited to single zone applications really. Hive is rubbish. The ones I've mentioned are much better suited to what you're looking for, especially as you have UFH which requires different control algorithms to radiators

 

[Steve Wegerle]

ok thanks, understood. So am I best off discarding my nest thermostats all together or can I use one nest for the house radiators + hot water, but adding a heatmiser for each underfloor heating zone? Is the alternative to put in a heatmiser setup across the whole house?

 

[muggles]

You could use Nest for some bits and Heatmiser for others, but then you'd have to have two different apps, which would get annoying fairly quickly I think

 

[ianmcd]

you cant use a Nest E to control your HW

 

[Steve Wegerle]

Thanks - I am tempted to leave the lifestyle thermostat in for the main house and at least give the nests a try with the underfloor given I've already bought them. If they are no good, I'll replace all with heatmiser setup

 

[ianmcd]

you can use the 3 Nest E to control your 3 heating zones and set the heating on the lifestyle to constant and use the lifestyle to control the HW if you want a nest to control the HW you will net to swap one of the Nest E to a dual channel nest

 

[Steve Wegerle]

Thanks ianmcd

 

[ericmark]

EPH are designed for zones, but does not seem to have any ability to connect to TRV heads, Nest no longer works with Energenie heads, Hive is not smart in any way and so the list goes on, there is no perfect system. Each system is a compromise.

So to basic idea, heat room only when required, means heat room fast, this does not line up with under floor heating as they are very slow, so only way it works is heat 24/7 so why worry about smart thermostats? To my mind UFH is great for an old peoples home where you want nothing that can burn so water can be kept cool, and you never turn it off.

On/off Zones to isolate a section of the house at certain times clearly works, I have a zone for my flat which is turned off when not in use, however although works with time be it hours or days, it does not work for temperature control, as the thermostat turns on/off too often, and stops boiler modulating, OK with oil boilers that don't modulate, no good with gas, temperature control is best with the TRV, how you control UFH I don't know, modulating boilers need controls which modulate and to be frank even with simple radiators it is hard enough.

So you may as well forget any idea of running the boiler so it can modulate correctly, it is not going to happen, all the systems are a compromise, best you can hope for is one that keeps rooms at correct temperatures. So looking at anti hysteresis methods, but even that your looking at what windows and direction they face.

They call the guys who fit central heating "heating and ventilation engineers" this annoyed me, I feel an engineer is educated to over level 3, however once I tried doing it, and got it wrong so many times, I realised why called engineers, working out what is required needs a lot of skill, once done keeping it running is easy, but the design is rather complex. After costing me a lot by getting it wrong, I would say well worth the money getting some one to design a system that will work in your home, and every home is different.

Personally I now use electronic heads on all radiators and each room is independent, and I use the hall temperature to decide when the boiler runs, thermostat could not really be more central. But last house same arrangement did not work, and house before was open plan, and house before that was gas hot air, every one was different, the hardest problem was a room with bay window getting the heating to turn off fast enough when the sun came out.

Yes geofencing is very nice, but hardly an option with UFH, not even worth considering, so why do you want smart heating and UFH they don't go together.