UFH below units

[Russell griffiths]

Morning all, so I know about not having pipes under kitchen units and stuff, so if I look at my ground floor and have a quick guess I would say 20% of the floor will have one thing or another on it so no pipes underneath. 

Does this not lead to cold areas of the slab, so making the system work harder as the cold areas pull heat from the heated areas. 

Would it not be better to heat the whole floor but to a lower temperature. 

Ta very much. 

[nod]

I had this conversation with a installer and was told don't put the pipes were fridge and freezer and don’t worry about the rest 

We have them under the kitchen Island as we had similar concerns as you  

[ProDave]

I don't have UFH pipes under the kitchen units, Fridge freezer, island, stove, or the corner where the pantry is going.

 

The heating works just fine, no "cold corners"

 

Here is my kitchen floor.  Kitchen units and stove at the left, Island in the middle, and pantry and freezer to the right.

[nod]

1 hour ago, nod said:

I had this conversation with a installer and was told don't put the pipes were fridge and freezer and don’t worry about the rest 

We have them under the kitchen Island as we had similar concerns as you  

I think I just marked out where the main two runs of units are 

Couldn’t do much where the island is as kitchen layout was not decided 

[Carrerahill]

5 hours ago, Russell griffiths said:

Morning all, so I know about not having pipes under kitchen units and stuff, so if I look at my ground floor and have a quick guess I would say 20% of the floor will have one thing or another on it so no pipes underneath. 

Does this not lead to cold areas of the slab, so making the system work harder as the cold areas pull heat from the heated areas. 

Would it not be better to heat the whole floor but to a lower temperature. 

Ta very much. 

I know from experience that temperature differentials on materials, typically timber based materials such as those used on kitchen cabinets and other fitted furnishing style doors can cause distortion issues. So as an example, a cool inside wardrobe caused by a draught in a floorboard and then the other side of the door on the warm heated side of the room can cause doors to start to bend inward slightly as a result of the warm side drying out the materials. I had this happen on some custom doors in my understaid drawer units - they look stunning and we get a lot of comments about how smart they look, but what most don't notice is that most of the drawer fronts (range from 450mm - 2200mm in height over the diagonal) have taken on a slight outward bow from the edges. It really annoys me.

 

So bear this in mind if you do fire in heat below cabinets and the impact it may have on them - I could foresee doors going out of alignment etc.

 

This problem is known to the extent that Hafele do tensioning systems that are rebated into the backs of door/drawer fronts to pull them straight again. 

Edited September 26, 2019 by Carrerahill

[Ed Davies]

For a modern house where the slab is no more than a few degrees (at most) warmer than the room and held at a steady temperature I can't see it making much difference whether there are pipes under the cabinets or not. As @Russell griffiths said, not putting them under just means the flow temperature needs to be a bit higher which might matter depending on how your loops are organized.

 

I can see the point of not putting them under the fridge or pantry but wouldn't you need some sort of thermal break in the slab for that to make much difference?

[Temp]

I would also avoid putting pipe where the WC pan will screw down :-)

 

2 hours ago, Ed Davies said:

I can see the point of not putting them under the fridge or pantry but wouldn't you need some sort of thermal break in the slab for that to make much difference?

 

We have two rooms each with their own loop. You can feel the floor screed is cold at the doorway between the two where we have no UFH pipes. I would just make the unheated area a bit bigger than the footprint of the fridge - say 8" to 10" " around it.

[Nickfromwales]

I think it is near impossible to thermally isolate 1m2 of slab in a well insulated  house.

3 hours ago, Ed Davies said:

but wouldn't you need some sort of thermal break in the slab for that to make much difference?

100%  

[MrSniff]

Where we replaced the kitchen adding a return, I laid out polystyrene insulation under the cabinets with the aim of at least keeping the food waste bin from simmering gently. No idea yet if this will make a difference...

[Onoff]

2 hours ago, Temp said:

I would also avoid putting pipe where the WC pan will screw down ?

 

 

Have a wall hung pan and you can have the loop underneath to keep you feet toasty. 

 

I didn't have the loop under my bath as it's half sunk and there's no slab there anyway just 3/4" marine ply onto the pir.

 

Also nothing in the cupboard where the linen bin lives (lower left corner). Didn't want to be warming smelly clothes.

 

Watch out having UFH pipes too near to your shower waste as it can dry the trap out. My waste is a wall drain behind the perimeter insulation so not an issue for me.

 

 

 

 

 

Edited September 26, 2019 by Onoff

[Russell griffiths]

26 minutes ago, MrSniff said:

Where we replaced the kitchen adding a return, I laid out polystyrene insulation under the cabinets with the aim of at least keeping the food waste bin from simmering gently. No idea yet if this will make a difference...

I wonder if this could work, could you have heating in the entire slab but add additional insulation under units to keep the heat from rising up under the units. 

Silly idea. 

What you think peeps.