Screed Depth ~ UFH Efficiency

[Dave Jones]

The site below states screed with a depth greater than 65mm reduces heating efficiency. Doesn't seem right, surely the more depth the greater the size of the emitter. Ok it would take longer to heat up initially but would be a greater thermal mass therefore thicker = better ?

 

https://www.nu-heat.co.uk/blog/underfloor-heating-screed-depth-drying-time/

[PeterW]

They say all sorts on that site, not all of it being correct … heating efficiency isn’t affected by depth, the time constant and potential for overheat however is greater depending on the control mechanism used 

[Rishard]

I was in the understanding that thicker was better, acting more like a night storage heater. I guess it all depends how well insulated the house is and how reactive you want the heating to be? It seems most with thicker slabs and good insulation are heating overnight where more mass is preferable? 

[JohnMo]

All depends on how you live in your house.  Some want UFH to operate like rads, because they are out all day, so thin is better. Steady room temp or batch charging floor, thick is better.