Smart thermostat for new (old) house

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We moved to our new to us bungalow, at the end of November. After lots of fixing and getting things sorted, I am now looking at getting a smart thermostat.

Currently, the house has an older system boiler setup. It is a Worcester boiler, estimated to be about 12-15 years old, and a hot water tank In the airing cupboard.

It has a Sunvic Select 207xl controller underneath the boiler on the wall and a thermostat in the hallway.

Currently, it's setup to turn the hot water on in the morning and evening, and the heating is similar. The thermostat in the evening however doesn't seem to make a difference, and the heating seems to just keep blasting on and on, unless I turn it off at the controller.

I have a feeling, out first bill is going to be pretty nasty. I've looked at the settings on the controller and can't really see why it won't turn off via the thermostat in the evening. Also the thermostat dial doesn't seem accurate.

So im looking at getting a smart thermostat. Seemed to have narrowed it down to turn Tado X or Hive.

Id need hot water and heating control. I will upgrade the boiler to a combi at some point next year but I don't know when, so this is the best option to control it for now.

Which one do people recommend. Also, do I need a wireless or wired one? I was getting a little confused by this. Current thermostat is on the wall in the hallway and is wired.

 

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A combi isn't an "upgrade", it is just a different type of boiler. When I did my full refurb I opted for an unvented tank and system boiler. My shower is like a jet washer now

Combis are typically oversized because they need to drive showers, which makes them pretty inefficient for normal heating duties (low and slow over a long period of time).

Get a thermostat that supports OpenTherm to be fractionally future proof. The Hive isn't. I'm not sure if the Tado X is either - but the earlier EU versions of Tado certainly were.

A mistake I made when I did my new boiler was not getting the proper Vaillant wiring center and Vaillant controller. That would have given proper weather compensation and flow temp modulation. So don't overspend because if you do replace it later on, you may want the OEM controls of whatever you end up with.

Isn't that what newer builds are doing now? I always thought a combi is better, because you are only heating the water you are using, rather than heating water to a tank and then keeping that water hot too?

 

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I have Tado (non X) for a couple years. Per room thermostats on a schedule is game changing. Highly recommend.

Yeah that's what I will do with trvs but just want a useful properly working schedule and thermostat for the time being!

 

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The loss is absolutely negligible. You may have an old vented tank at the moment but newer ones are weapons grade. Mine lives in the attic which is like 4 degrees atm. Plus solar can be diverted to water if you have a tank.

Both have their place but neither are upgrades on each other. Just different solutions

Yeah, I have an old vented tank in the airing cupboard in the bathroom at the moment, and the gravity tank in the loft. I will look at solar at some point as well but there is so much that needs updating here.

My previous house, new build, had a tank. When we did the boiler on this new house, we also did boiler with tank. Multiple plumbers recommended that to us since we have 2+ showers/baths.

Interesting, so already two votes for boiler and tank. Ill get some quotes for that too then. We only have one bath with shower tap

 

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yep - lucky him if he's got a non-condensing system boiler that will last for 30years and not need replacing every 10 (neighbours just had his done 2mnths back .. hope I'm not next)
is it a modulating boiler that can reduce power to match the needs of the house demand without cycling on/off ? if so you are all set.
Parents old style boiler was fine with a dumb thermostat, though, turned off/on with the temperature from the thermostat location(living room)
since you can't optimise a multi-zone (like kitchen+living room ..maybe that's why people want open plan) with smart, I think they are over sold;
that inadequacy makes a nonsense of having bells&whistle of external temp mon.

It's a Worcester Green star 24ri and about 14-15 years old. I don't think it does any modulating.

 

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Do you think that's the only measure of better when it comes to a boiler / heating system? Do people only care about marginal cost savings rather than quality of the bathroom experience?

Any more than one bathroom / 2 people and they're unfit for purpose as they can't deliver two decent showers at the same time.

It's the measure for me, as I have one bathroom and 2 people. I have absolutely no need for a tank full of hot water sitting there waiting.

 

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That's a condensing and also modulating boiler, if it's been properly maintained then it's barely any different to any other modern heat only boiler. A Hive would be a simple step into the smart control world without breaking the bank of it got replaced at a later date. Having TRV'S across the rooms is a must to regulate room temperature though.

I couldn't find any concrete evidence that it was properly modulating and supported opentherm

 

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It's likely you'd never make back the cost of re-plumbing the hot water system to get rid of the tank. Not to mention, you'd have to go back to a tank if you ever got a heat pump in the future. I'd personally spend the money on a modern hot water tank and system boiler and leave the rest as-is.

I'm not against doing that, I just didn't know it was the way to go now.

It does make sense for future proofing to keep it that way, plus being able to use solar too.

 

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WB 24Ri
Gas modulation yes, Opentherm No.
Gas modulation reacts to boiler temperature, Opentherm reacts to house temperature.

There are various control methods from various manufacturers, you really need a site survey from a professional, and then a chat about what you would like to do in your house.

I fitted an Atag boiler for a friend last month, weather compensation at the boiler & a Nest smart thermostat over Opentherm. A nice setup, that ticked all the boxes, will modulate down to 5KW, and it was nice to see the Nest app access DHW (Combi) control over the Opentherm connection.

Thanks for explaining the modulation and opentherm terms, it makes more sense now!

I will get someone to come and do a survey at some point, but we have just moved in, and I can't afford a new boiler at the moment. So I don't want to waste anyone's time. For now, I just want a bit more control over the current system and to save me some pennies for the rest of the winter.

 

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The OP heating set-up sounds somewhat similar to mine. Basically the controller has 2 channels, 1 for hot-water, 1 for heating. The separate thermostat controls the heating, but not the hot water.

The problem i see with just changing the thermostat for a digital/wireless one, is that it will not be able to control the hot water, that will still be controlled by the existing controller. In my case, when I looked at it, it appeared the least work solution was to replace the CONTROLLER, and put wireless controlled valves on the radiators and simply bypass the old room thermostat.

Didn't get round to doing the above.

Hive, Tado and I think wiser can all control heating as well as hot water. You just need to buy the right one.

The problem I have is, if I go with Tado, they only offer a wireless one for Tado X which controls hot water too. But I have a wired thermostat. Don't know if that matters or not?!

 

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The wireless one will have a receiver which would then get wired into the system - it'll just make the original wire redundant


EDIT: Just to add, if you were willing a drop a little extra cash and get a modern hot water tank too, it's likely it'd come with a slight rejig of pipes allowing for a modern boiler that will do load and/or weather-compensated flow temperatures for radiators (lower temp = more steady heating, more efficiency, more comfort etc) and PDHW (priority domestic hot water) which would then increase the flow temperature up to 60-65ºC to the hot water tank only to top it off, then go back to heating the radiators at the lower temp.

Great, thanks!

I think getting a decent hot water tank and new boiler is the way to go it seems. Or do you mean get a better hot water tank now, and change boiler later?