UFH Running cost difference with 6mm verses 10mm insulation board - Tile Advice

[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!

 

[widler]

Id like alan to just clarify that it does not need insulation board, cos it makes a big difference in height and cost as well

 

[Rookery]

As its a chipboard floor the OP is talking, I wouldnt tile directly to it heated or not. I'd be using 6mm Marmox or similar. On an unheated floor I might use 6mm Hardie or the Marmox type, depending on price, availability, stock etc.

 

[Ajax123]

Id like alan to just clarify that it does not need insulation board, cos it makes a big difference in height and cost as well

No that is not for me to clarify. Insulation will make a difference but it is not a significant difference in terms of cost saving in the running costs. It is for whoever is taking design responsibility to decide whether or not the inclusion of insulation is appropriate.

 

[widler]

, i only read it the other month looking for advice on eufh, as the customer didnt want the extra hight of boards,cos of washing machine, dryer not being able to fit with the extra hight, but i told them its a must,.
so nearly 30m2 of boards,taking the worktops off, lifting units, retiling walls,redecorating was not really needed,just cos i read on here it was needed as it would heat the concrete and cost a fortune , kinda puts a downer on the whole jib really, i hope the customer does not come on here and read this, he will not be a happy chicken, as im not

 

[beanz]

, i only read it the other month looking for advice on eufh, as the customer didnt want the extra hight of boards,cos of washing machine, dryer not being able to fit with the extra hight, but i told them its a must,.
so nearly 30m2 of boards,taking the worktops off, lifting units, retiling walls,redecorating was not really needed,just cos i read on here it was needed as it would heat the concrete and cost a fortune , kinda puts a downer on the whole jib really, i hope the customer does not come on here and read this, he will not be a happy chicken, as im not

Just look at it this way.. You've done your very best for the customer, and done everything you can to help reduce his long term costs. A lot of people end up turning the heat off anyway once the novelty has worn off, and the bills start to come in.