UFH Advice Needed - Renovation & Extension

[renovator]

HI All!

 

So I'm about to embark on renovating and extending my mum's 2001 3 Bed detached property. I've attached the architect's floor plan which is effectively a full width rear single story extension and re-adjustment of interior walls to create a larger hallway and open plan living. I've researched into UFH vendors and approaches to reduce the amount of heat loss in the property and have a few questions:

 

1. The existing slab is believed to have 75MM of insulation underneath. I'm considering a low profile wet system to sit above but wanted to check to see if I should add something a Kingspan Optim-R (25mm) followed by the UFH system?

2. I've had a quote from two providers for supply only; Wunda EPS400 (3 zones, 5 port manifold covering ~51SQM): £2,441) | Nu-Heat were more than double the Wunda quote.

3. Final question is what labour would I need to approximately pay to install the UFH system?

 

Any thoughts on the above so far and should I also obtain a quote from https://www.outsourcedenergy.co.uk/shop/ as they seem to be recommended by a few on this forum.

 

I really appreciate your advice on this.

 

Thanks!

 

 

[JohnMo]

If you only intend to have 100mm insulation in total, I would keep my money in my pocket, by not doing UFH. 

 

The downward heat loss will empty your pockets for ever more.

 

Your heat loss downwards is based on UFH flow temp and the ground temp. So say 36 deg flow temp and 6 deg ground temp., So you have a delta of 30 deg.

 

If you had radiators the room temp and ground is used to find the delta T, so 21 - 6 is 15.

 

Heat loss is based on the floor U value multiplied area, multiplied by delta T.

 

So everything else being equal, the downwards heat loss is double with UFH compared to radiators, because the delta T is double with UFH compared to radiators.

[renovator]

Thanks John,

 

I've been checking with the builder to see how we can reduce heat loss by increasing insulation significantly in the new extension. So it will be 200MM insulation in the new 3.5M extension and have potentially one additional radiator in the hallway. Thoughts?