UFH Running cost difference with 6mm verses 10mm insulation board - TilersForums.com

[JimboD]

Hi all, fairly obvious post as the title suggests. I'm beating myself up as 10mm would obviously provide more insulation (laid on solid chipboard floor in bathroom) but how much difference? Would really prefer to go with 6mm due to the step down to the landing carpet.

i can't seem to find any real world data on this topic. Will running 6mm cost be hundreds of pound more a year or a few pence? I've no idea....

Also how much difference will using a cement coated board make as that further reduces the core insulation thickness. I'd prefer a cement backed board I suspect it will make it easier to fix the ufh wire to with the tape so it won't come away and float up when I apply the slc.

any input appreciated


cheers all!

 

[Ajax123]

With 6mm insulation??? you might as well put tin foil down really. Neither 6 nor 10 will give you a huge impact TBH.

 

[JimboD]

With 6mm insulation??? you might as well put tin foil down really. Neither 6 nor 10 will give you a huge impact TBH.

Wow, really. So why have 100s of thousands of boards like this been sold? It cant just be a marketing spin. I'm sure I've seem some warm up time data somewhere showing the time to get to 24oC went from 2 hours to 30 mins using just 10mm of insulation. But I think that was on a concrete floor.

Perhaps that is what you mean? As the floor is chipboard, with good insulation underneath between the joists and rooms below that have central heating, the increase in insulation with 6 or 10mm of board on top will be negligable compared to if it was a ground floor room with a concrete base?

 

[widler]

With 6mm insulation??? you might as well put tin foil down really. Neither 6 nor 10 will give you a huge impact TBH.

Bloody hell really alan .
So when doing eufh you may as well not bother putting boards down on the floor at all , just straight over the substrate ?
I thought the boards were to stop heat warming the substrate instead of the tiles ?

 

[beanz]

I must admit, I never bother with insulation boards in an upstairs bathroom.

 

[John Benton]

I must admit, I never bother with insulation boards in an upstairs bathroom.

Me neither, it gets warm enough reasonably quickly upstairs. Last one I did have central heating pipes running underneath before floor was switched on, and that was heating the floor in a direct line above the pipes very quickly

 

[Ajax123]

Wow, really. So why have 100s of thousands of boards like this been sold? It cant just be a marketing spin. I'm sure I've seem some warm up time data somewhere showing the time to get to 24oC went from 2 hours to 30 mins using just 10mm of insulation. But I think that was on a concrete floor.

Perhaps that is what you mean? As the floor is chipboard, with good insulation underneath between the joists and rooms below that have central heating, the increase in insulation with 6 or 10mm of board on top will be negligable compared to if it was a ground floor room with a concrete base?

Sort of. No what I meant was the difference in efficiency between 10mm and 6mm when it comes to running cost is likely to to have little impact.

Now the science bit.... Haven't got the figures available for chipboard but if you do a rough u-value calculation for a floor of 10m2 (5mx2m) with one exposed wall of 5m and a screed of 10mm having a thermal resistance of 0.0045m2K/W

you get a u-value of 0.61w/m2K with the 6mm board (assuming the insulation has an r-value of 0.023W/mK and a value of 0.58w/m2k with the 10mm board. In other words not much difference. Probably pennies per year difference rather than hundreds of pounds.

 

[Ajax123]

no insulation at all you get 0.73w/m2k.... A small difference.

Of course all that said I am now at the age where I believe you can never have too much insulation....specially at this time of year

 

[widler]

So does this only mean on chipboard floors,not concrete and the like ?

 

[beanz]

So does this only mean on chipboard floors,not concrete and the like ?

I think what Alan's saying, is that there's so little in the way of saving pennies, that it's not worth the extra work/expense of using the boards at all!