Best way to plumb and then control our new heating & hot water system in old house...

[andymet87]

Hi all,

I know there are lots of threads out there on this however I have a rather specific situation and would appreciate any advice that can be offered..!

We are currently renovating and extending an old cottage (first written record of it is in 1770 but it is probably older). It is not listed but we are doing everything we can to be sympathetic to its heritage etc... Over the years it has had a number of inappropriate works that we are currently trying to resolve so our works are quite extensive... Part of these works involved removing a concrete slab and we are putting limecrete (breathable) base back in. When we are done the house will consist of:

Downstairs (low ceilings)

• Kitchen/Diner
• Utility
• Large Hall
• Study
• Lounge

Upstairs

• 4 x Bedrooms
• Ensuite
• Family bathroom
• small landing area

Due to the nature of the house it's thermal performance varies enormously from room to room, for example the kitchen/diner will be in the new extension and conform to current building regs whilst the lounge has solid walls and the hallway wall is in one place only a single skin brick wall...

Downstairs we are having underfloor heating throughout, the intention is that each zone will have a thermostat which will enable the system to react to the different circumstances in each area, maintaining a steady temperature through the house. This is the standard system utilised for (wet) underfloor heating systems.

Upstairs there will be radiators (probably column radiators from https://www.columnrads.co.uk/) and there is an ongoing debate over how to plumb and then control this system. Our plumber would like to install a normal system with a thermostat controlling the "upstairs zone" and TRV's on the rads. The thermostat would go on the landing. I have concerns over this system because:

1. the upstairs walls are similar to the downstairs and range from current buildings regs compliant walls to a 100mm timber frame tile hung wall
2. TRV's don't look good on the column rads in my opinion
3. the landing will be quite warm due to the heat rising from the large hallway below which will mean the thermostat rarely triggers.
4. Due to the nature of the house we want to minimise gadgets on show, we also want controls out of sight or lockable so children/visitors cannot alter the settings easily.

I have suggested the upstairs radiators are controlled by a manifold and each room has a thermostat (or digital thermometer) controlling the manifold. Which system would control this I don't know but am researching Fibaro, Honeywell Evohome, the 12v heatmister system with control pad, etc...

I like the 12v heatmister system as it could control a manifold for the upstairs rads perfectly but would prefer it if the thermostats in each room were "dumb" and you couldn't alter settings from them...

I fear I am overthinking this all but if anyone has any thoughts they would be appreciated..!

First fix is due in a few weeks so I need to make a decision asap...

 

[bernardgreen]

the landing will be quite warm due to the heat rising from the large hallway below

In my cottage of similar age with doors upstairs that do not fit snugly my experience is that the upstairs rooms are for the most part well heated by the warmth rising up the stairs. and from heat rising through the ceilings. Hence the radiators in the upstairs can be smaller than one would expect. ( heating the bedrooms with out the heating on downstairs might be problem )

Downstairs we are having underfloor heating throughout,

With low ceilings there might be a problem fitting adequate thermal insulation between the ground and the UFH pipes. Excavating down to obtain enough depth for insulation without raising floor level has to be done very carefully to avoid affecting the walls which almost certainly have little or no depth of foundation

 

[andymet87]

In my cottage of similar age with doors upstairs that do not fit snugly my experience is that the upstairs rooms are for the most part well heated by the warmth rising up the stairs. and from heat rising through the ceilings. Hence the radiators in the upstairs can be smaller than one would expect. ( heating the bedrooms with out the heating on downstairs might be problem )

Thanks and noted, is that even with minimal, if any, insulation?

With low ceilings there might be a problem fitting adequate thermal insulation between the ground and the UFH pipes. Excavating down to obtain enough depth for insulation without raising floor level has to be done very carefully to avoid affecting the walls which almost certainly have little or no depth of foundation

We have already excavated and about to lay the pipes in, we took the concrete slab up and are installing a Sublime floor (see https://www.lime.org.uk/application...blimer-limecrete-floor-insulation-system.html). We were worried about the footings but it turns out they aren't too bad! underfloor heating is feasible and being fitted next week

 

[bernardgreen]

Thanks and noted, is that even with minimal, if any, insulation?

The insulation is the thatch, the eves are about 2 feet above floor level.

 

[Dan Robinson]

You can get thimble or button that report back to that rooms thermostats located out of site. As well as a floor sensor.

Heatmiser can do them natively and an installer in the know can also make it work with Honeywell Evohome. The latter also has dumb sensors that can be used to temporarily boost or reduce a zone by a few degrees.

 

[andymet87]

Thanks for that - wasn't aware of the "thimble sensor" but am now researching that.

it turns out that using a manifold is unlikely to work as the actuator wouldn't react quickly enough to shut off the radiator. 5 x valves off the system however would work so will look into that and whether it is a feasible option.

 

[Dan Robinson]

What is the heat source?

 

[andymet87]

What is the heat source?

Currently the plan is to have a Potterton Promax 24HE boiler with Heater Megaflo 210 unvented cylinder (as specified by plumber).

that said, the house is currently a shell with no plumbing other than the mains water inlet so it can be whatever (so long as it's powered by mains gas!).

 

[Dan Robinson]

Well that boiler is total cack. Get a decent one, Intergas for example and run hot water priority and compensated Heating and the reaction time of the valves becomes a non issue.

 

[andymet87]

Given the amount of work that we're doing cost is a big consideration - our priority is getting a good long warranty at a sensible price.

To be honest the above was what he included in his quote and I have advised him I am likely to specify a different one when the time comes, always open to suggestions

 

[Dan Robinson]

It is a big consideration yes, but it is also essential equipment and one of the things that should be high up the list over carpets and curtains etc.

 

[andymet87]

one of the things that should be high up the list over carpets and curtains etc.

- don't worry it is, not anywhere near thinking about that stuff yet! Main priority atm is sorting first fix

 

[andymet87]

which boiler where you referring to Dan?

 

[Dan Robinson]

Intergas Eco RF has a 10 year warranty. The SB has 7.

 

[andymet87]

So our underfloor heating is going in atm and the plumber is raising concerns about out chosen control system and how it will need to be plumbed...

We've opted for a Heatmiser Neo system, each bedroom, each downstairs room will have their own zone, the two bathrooms will be controlled together on one zone.

This will leave us with 10 zones in our house...

All thermostats (bar the one in the modern kitchen) will be located in the boiler cupboard with remote thimble sensors.

For the 5 downstairs zones the thermostats will connect to a Heatmiser UH8 - 8 Zone 230v Wiring Centre, which will in turn control the actuators on the manifold and boiler etc...

For the 5 upstairs zones, we propose to have 5 separate rings controlled by motorised valves. Each thermostat (or timer for the bathrooms) will control the boiler and a motorised valve.

We will have a further controller for the hot water...

All rooms will be controllable from the boiler cupboard (apart from the kitchen) or online (via phones etc). Heatmiser are soon to release a Neo-Ultra stat that can controll all zones in the house. When released, we will install in place of the kitchen stat to enable us to control everything from the kitchen.

Our cottage is old, and we are very aware of the need to minimise visual gadgetry, hence removing all TRV's, electric stats on the walls etc from the system. Our plumber is not convinced and thinks we're spending more money for little benefit...

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Any thoughts on this setup?

Is this overkill?

Would you install a system like this?