Insulation Boards thickness

[jimbo]

What are the advantages of 20mm boards against 10mm boards on top of concrete slab. Would the underfloor heating on top heat up any quicker or would the thicker board just prevent the heat from dispersing less

 

[Qwerty]

Both. Faster warm up time and less heat loss

 

[GoneGuy]

And also cheaper to run as less heat loss

 

[Tile Fix Direct]

The thicker the insulation the more you insulate the floor from the cold slab. This will mean you will not need to turn the heating on as much, and when you do it will use less energy for a given room heat.