Heating (UFH) control

[richo106]

Hi all

 

I am getting to the stage in my build where I am considering thermostat locations/control

 

I am aiming for air tightness of 3, having MVHR installed, ASHP, UFH ground floor in screed, UFH first floor using spreader plate. Insulation level are 0.18 walls and 0.12 floor and ceilings

 

I am happy with the layout for the UFH (attached) but my question is that is it necessary for each room to have its own thermostat?

 

Or would it be ok to have 1 thermostat per floor? And where would these be located?

 

I have never had ASHP or UFH, is it best just to leave the thermostats set at say 20 degrees and not touch then? 
 

All information appreciated 

[richo106]

Currently they have quoted for a thermostat in most of the rooms, 13 in total.

 

Is there anything specific needed for building regs?

[JohnMo]

Firstly I find it bonkers how much pipe these companies specify for a well insulated house. I would increase the pipe spacing to 200mm, or even 250mm, I would have no dedicated loops in hall ways, just use the pipe going from the manifold to the room spread in the centre of the hall at 200 to 250mm centres.

 

I would have a max of two zone, one up and one downstairs. It is unlikely your upstairs will require much heat, as it will borrow from the downstairs.

 

Put the thermostats in the hall away from draft and the sun.  Once you get the system up and running you will need to balance the flows to get the room temps where you need them.  Run the whole lot on weather compensation. Your flow temps should be low enough that if the sun heats a room the UFH will stop giving out heat naturally in that area as the floor temp will only be a couple of degrees hotter than room temp.

[JohnMo]

Use wireless thermostats as these can be moved easily to find the ideal location 

[ProDave]

1. DO NOT waste your time and money laying UFH pipes on the upstairs landing.  The WILL NOT ever get used, more than enough heat from downstairs.  Yet the professional designers still show this.

 

Just fit a normal programmer and individual room thermostats.  It will tick a lot of boxes for building control and SAP assesment.  Many will say you don't need individual room stats but that really only works with a very well insulated house and if you take the time to balance the rooms properly.

 

As above wider loop spacing, and even wider upstairs as that will need little heat.

 

If you are fitting mvhr, don't aim for ACH 3, aim for ACH < 1  Why not aim for the best you can get?  to do it properly at build is little cost, it is all in the detail.

 

I would put the downstairs manifold under the stairs then just rely on the heat from the pipes passing too / from the manifold for heating the hall.  The hall has so little external wall the heat loss is tiny.

 

[Lofty718]

Closer pipe centres allow lower flow temperatures but I don't think there's much in it.

 

Zoning is bad for efficiency, you have the right idea with just one zone for upstairs and one for down. The companies will try and sell you a load of crap you do not need.

 

Ideally you want your UFH running on weather compensation.