Discuss New central heating system - Advice needed on choice of thermostat for zoning. in the Plumbing Forum | Plumbing Advice area at PlumbersForums.net

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Hi all,

Having just purchased my first house, I have just started a whole of house refurbishment project.

I am going to be putting in a new central heating system. The boiler I've chosen is the Vaillant Ecotec IQ Combi boiler (35kw). I wanted advice on zoning and the best smart thermostats (app/internet enabled) to help with this.

I wanted a simple two zoned system for upstairs and downstairs.

Upstairs all the bedrooms will have radiators and bathroom will have wet underfloor heating possibly with a small heated towel rail as secondary source of heat. Downstairs there will be radiators in the lounge and the hallway with underfloor heating in the kitchen and downstairs toilet.

I need advice on the best thermostat to help control the two zones. I'm not a heating expert but understand you'd need a separate wall thermostat for each zone. I was originally looking at Nest but was put off by the price of purchasing two thermostats.
So I have shortened my options to:

  • Hive (adding another thermostat is £99 which is reasonable)
  • Drayton Wiser (using thermostats but potentially adding their iTRVs
  • Vaillant VRC 700 (this seems to be Vaillant's answer but not seen too many reviews)
I am keen to gather people's experiences and opinions on either of the above options.

Thanks
 

EvilDrPorkChop

Gas Engineer
Advent Win
Don't bother with the GreenIQ, i've fitted a few and tbh had some hassle with them. Get the Vaillant EcoTec Plus instead - a very good boiler. The Green IQ is good but a bit too clever for it's own good, we only fit Vaillants but I won't be fitting any more GreenIQs.

Thermostat - out of them 3 i'd be going Hive.
 

EvilDrPorkChop

Gas Engineer
Advent Win
Wont the underfloor heating be a seperate zone?
I hadn't read that - just thought it was upstairs and downstairs....I'm counting 4 zones. 2 UFH zones and 2 Radiator zones?

Taking that into consideration i'd have Honeywell EvoHome and zone the rads too, but all depends on budget.
 
Don't bother with the GreenIQ, i've fitted a few and tbh had some hassle with them. Get the Vaillant EcoTec Plus instead - a very good boiler. The Green IQ is good but a bit too clever for it's own good, we only fit Vaillants but I won't be fitting any more GreenIQs.

Thermostat - out of them 3 i'd be going Hive.
Hi EvilDrPorkChop,
I had chosen the Green IQ due to its clever modulation technology and efficiency rating. I have an Ecotec Plus 32KW in my current home and never had any issues. I think I was sold by the higher hot water output. Just about to order it so I'll take a look at the 35kw EcoTec Plus!

I hadn't read that - just thought it was upstairs and downstairs....I'm counting 4 zones. 2 UFH zones and 2 Radiator zones?

Taking that into consideration i'd have Honeywell EvoHome and zone the rads too, but all depends on budget.
Scott_d & EvilDrPorkChop - being a complete novice, I'll assume that each UFH area on it's own is a zone in itself. You've given me food for thought here. I definitely want wet UFH for the kitchen as it's a large tiled area. However for the two bathrooms I am open to having Electric UFH instead with heated towel rails powered by CH. It would only be used for short periods in the colder months.

So that should leave 3 zones - Upstairs rads, downstairs rads and kitchen UFH. I'm aware that the electric UFH would need a separate thermostat system such as Heatmiser or Nu-Heat etc.

If I go down the Hive route would I need 3 separate thermostats? Assume the same for Nest but using Evohome or Drayton and their radiator valves each room is effectively its own zone, right?
 

Brambles

Advent Win
Evohome, is probably the most effective control system for your proposed system, with total flexibility on zoning. Around £500 for the controller and one UFH zone plus £50 for each radiator.
 

SimonG

Plumber
Advent Win
And don't make the mistake most people do. The towel rail wont provide additional heat, not once its insulated with all them nice towels.
 
Evohome, is probably the most effective control system for your proposed system, with total flexibility on zoning. Around £500 for the controller and one UFH zone plus £50 for each radiator.
Hi Brambles thanks for your advice, I went through the evohome official site to build my system. Putting aside the cost I was advised to order:
  • Wifi Base pack
  • In wall power supply
  • Wireless digital room thermostat
  • Radiator zone kit (9 pieces)
  • Wireless relay box
Does that sound about right to you? I am wondering where the wireless room thermostat would go? Would that be used for the UFH? How would that be connected up? I

'd use the main base screen as the overall controller for the house along with app control but am curious to see how the UFH bit would work.
Post automatically merged:

And don't make the mistake most people do. The towel rail wont provide additional heat, not once its insulated with all them nice towels.
For both bathrooms I think I'll put electric underfloor heating for the colder months as it will be tiled. Towel rail typically isn't enough I'm aware though I plan to put in one with high BTU if that helps. So ordinarily I expect it will suffice but for when it's really cold I'll run the UFH for half an hour in the morning and then maybe in the evening if required.
 

Brambles

Advent Win
Tazzy:

The complete list of equipment required:

1No. connected thermostat ( ATP926G3001)
- it comes with the wireless transmitter BDR91

Mounting plate if you don’t want it free standing but wall mounted (AFT600)

HR91 Controller for each radiator

HCC80R controller ( up to 8 zones) for the wet underfloor heating system.

The connected thermostat is the main / central controller, it can be used as a room thermostat too ( if required). I only use them as a zone thermostat for an underfloor heating zone ( to save the cost of an additional thermostat). The HR91’s are very effective room thermostats and can be optimised to suit your room requirements ( long curtains / doors / open windows et al)

For a second UFH zone you will need a further Honeywell simple wireless thermostat.

Don’t try to control electric UFH through the Evohome System - it does not do it very well!

If you do go down the Evohome route - follow the installation instructions to the letter. You can set up the whole system on a table if required and thoroughly test it before you attach it to your heating system. Just take your time with it.

The BDR91 needs to be at least 600mm from any large metal object.

Ensure that all the bindings are only done once. It is very easy to double bind units - which gives erratic behaviour.

Keep the Connected Thermostat on a 240v supply - the rechargeable battery life is minimal when used in wireless mode.

Once set up, they are generally very effective and trouble free ( apart from replacing all the batteries every year!).
 
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EvilDrPorkChop

Gas Engineer
Advent Win
Tazzy:

The complete list of equipment required:

1No. connected thermostat ( ATP926G3001)
- it comes with the wireless transmitter BDR91

Mounting plate if you don’t want it free standing but wall mounted (AFT600)

HR91 Controller for each radiator

HCC80R controller ( up to 8 zones) for the wet underfloor heating system.

The connected thermostat is the main / central controller, it can be used as a room thermostat too ( if required). I only use them as a zone thermostat for an underfloor heating zone ( to save the cost of an additional thermostat). The HR91’s are very effective room thermostats and can be optimised to suit your room requirements ( long curtains / doors / open windows et al)

For a second UFH zone you will need a further Honeywell simple wireless thermostat.

Don’t try to control electric UFH through the Evohome System - it does not do it very well!

If you do go down the Evohome route - follow the installation instructions to the letter. You can set up the whole system on a table if required and thoroughly test it before you attach it to your heating system. Just take your time with it.

The BDR91 needs to be at least 600mm from any large metal object.

Ensure that all the bindings are only done once. It is very easy to double bind units - which gives erratic behaviour.

Keep the Connected Thermostat on a 240v supply - the rechargeable battery life is minimal when used in wireless mode.

Once set up, they are generally very effective and trouble free ( apart from replacing all the batteries every year!).
Save some money, if you've only got two UFH zones then you don't need the UFH controller. Just buy a T87RF set with a BDR91 for each zone (So two in your case) and set it up as an additional zone. Works out much cheaper - and you don't need to buy an additional stat.
 

Brambles

Advent Win
Above is correct - it will work, but Evohome won’t recognise it at a low temperature heating circuit - so it won’t quickly optimise it as a UFH. It will be treated within Evohome logic as a radiator with relatively short on/off periods, which ( as it is not ) the
UFH will probably repeatedly “hunt” the set point temperature.

Hope that makes sense.
 

EvilDrPorkChop

Gas Engineer
Advent Win
Above is correct - it will work, but Evohome won’t recognise it at a low temperature heating circuit - so it won’t quickly optimise it as a UFH. It will be treated within Evohome logic as a radiator with relatively short on/off periods, which ( as it is not ) the
UFH will probably repeatedly “hunt” the set point temperature.

Hope that makes sense.
It treats it as a zone valve rather than UFH. I’ve done this a few times, including my own house and don’t have any issues. It maintains the temperature perfectly.
 
Tazzy:

The complete list of equipment required:

1No. connected thermostat ( ATP926G3001)
- it comes with the wireless transmitter BDR91

Mounting plate if you don’t want it free standing but wall mounted (AFT600)

HR91 Controller for each radiator

HCC80R controller ( up to 8 zones) for the wet underfloor heating system.

The connected thermostat is the main / central controller, it can be used as a room thermostat too ( if required). I only use them as a zone thermostat for an underfloor heating zone ( to save the cost of an additional thermostat). The HR91’s are very effective room thermostats and can be optimised to suit your room requirements ( long curtains / doors / open windows et al)

For a second UFH zone you will need a further Honeywell simple wireless thermostat.

Don’t try to control electric UFH through the Evohome System - it does not do it very well!

If you do go down the Evohome route - follow the installation instructions to the letter. You can set up the whole system on a table if required and thoroughly test it before you attach it to your heating system. Just take your time with it.

The BDR91 needs to be at least 600mm from any large metal object.

Ensure that all the bindings are only done once. It is very easy to double bind units - which gives erratic behaviour.

Keep the Connected Thermostat on a 240v supply - the rechargeable battery life is minimal when used in wireless mode.

Once set up, they are generally very effective and trouble free ( apart from replacing all the batteries every year!).
Really appreciate all the details Bramble it's made things a lot clearer. I have just one more question that I'm unsure of.

If I don't get the HR91 for all of my radiators, say the heated towel rail in bathroom and maybe the hallway radiator which has standard TRV. Will these 'dumb' radiators heat up whenever any part of the system calls for heat? If we assume that HR91's are all programmed to whatever desired temperature at a set time, will the 'standard' radiators be heated whenever the boiler is required to heat on of the radiators with HR91 thermostats?
Post automatically merged:

Save some money, if you've only got two UFH zones then you don't need the UFH controller. Just buy a T87RF set with a BDR91 for each zone (So two in your case) and set it up as an additional zone. Works out much cheaper - and you don't need to buy an additional stat.
Will only have one 'wet UFH zone' which will be the kitchen. So would I'll need the one BDR91 I'm guessing? Have you used Hr92 TRVs before? What's the difference between HR91 and 92? I'm seeing these being offered with the base pack hence the question.
 
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Brambles

Advent Win
Tazzy,

Your assumptions on TRV’s are correct.

Apologies, I cited HR91 controllers, I meant to refer to HR92!

With Evohome, you can do it in stages, if a TRV distorts the system, you can always replace it with an HR92.

Apologies for any confusion
 
Thanks Brambles. Have either of you come across Tado? Just comparing this with Honeywell and wondering what your thoughts were?

Seems like functionally Evohome is definitely the one to go for but Tado looks better?!
 

Brambles

Advent Win
Tado is fine, in my view it is a quality system - once set up it is very reliable. From a customer perspective 60% of our sales are Evohome, followed by Nest, then Tado with Hive bringing up the rear. That is within the corridor of North London to Oxford.

Evohome comes into its own in a larger property where all the rooms are not used on a regular basis. In reality, you are not going to recover the capital cost of any of these systems (certainly not Evohome) over a short period. It is more about comfort and what fits your lifestyle. Evohome is (in my view excellent) but is old technology and (I stand to be corrected) does not appear to being actively promoted in Europe by Honeywell. I suspect that the new Honeywell product (if as and when it is launched) will be completely different and not compatible with existing Evohome.

We are currently trialing Netatmo in two properties - too early to say how they are performing (need to get through the winter) - but the concept is different to the existing control systems on the market.
 
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