UFH Running cost difference with 6mm verses 10mm insulation board

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UFH Running cost difference with 6mm verses 10mm insulation board

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Discuss UFH Running cost difference with 6mm verses 10mm insulation board in the Canada Tile Advice area at TilersForums.com.

J

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!
 
J

JimboD

Ajax123 said:
With 6mm insulation??? you might as well put tin foil down really. Neither 6 nor 10 will give you a huge impact TBH.
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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

widler

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Ajax123 said:
With 6mm insulation??? you might as well put tin foil down really. Neither 6 nor 10 will give you a huge impact TBH.
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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 ?
 
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John Benton

John Benton

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beanz said:
I must admit, I never bother with insulation boards in an upstairs bathroom.
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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
 
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Ajax123

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JimboD said:
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?
Click to expand...

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.
 
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widler said:
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
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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

widler

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, 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
 
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beanz

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widler said:
, 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
Click to expand...

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.
 
J

JimboD

I think there must be big difference based on the substrate. If the eufh is sat on concrete the energy will be spent warming the concrete block whereas if sat on wood (a naturally good insulator) the energy will go into heating the tiles above.

So if this is the case then really all anyone needs upstairs on a wooden floor in a well insulated centrally heated house is either to put the eufh directly on the wood (usually chipboard in a modern house) if there is no movement and flexible adhesive is used or as nearly everyone suggests board it first with some Hardie to provide a better tiling surface or if height is an issue use a membrane like Ditra.

I'm a diyer not in the trade so apologies for opening this can of worms.....

jim
 
widler

widler

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beanz said:
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.
Click to expand...

"just have a think about how the heat mat works and how concrete absorbs heat. the concrete floor will act as a heat sink. You want the heat to radiate upwards not down into the concrete. If you dont put insulation down your heat mat will take several weeks to warm up and will cost you a huge amount of money. The more insulation you can put between the concrete and the heat mat the better. If you have no height available to do this you may be better to consider a different heat source.

in a nushell as Dave says...... Yes it is"

Beanz, this is just one thing I read the other month.
Personally I'd insulate every floor , this above sounds right to me,and Alan wrote it,and everyone on here agreed,he must of had a tipple last night ;)
Good day to you all,I'm off to work
 
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Ajax123

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JimboD said:
I think there must be big difference based on the substrate. If the eufh is sat on concrete the energy will be spent warming the concrete block whereas if sat on wood (a naturally good insulator) the energy will go into heating the tiles above.

So if this is the case then really all anyone needs upstairs on a wooden floor in a well insulated centrally heated house is either to put the eufh directly on the wood (usually chipboard in a modern house) if there is no movement and flexible adhesive is used or as nearly everyone suggests board it first with some Hardie to provide a better tiling surface or if height is an issue use a membrane like Ditra.

I'm a diyer not in the trade so apologies for opening this can of worms.....

jim
Click to expand...
Yes the u values will be affected by the substrate. It's to do with three basic elements. Thermal conductivity, the higher it is the more heat it will transmit, thermal resistance which is provided by insulation to overcome thermal conductivity and then specific heat or latent heat capacity which is a measure of how much energy it takes to produce the thermal inertia required to get the heat coming out of the floor. The actual insulation will work the same way regardless of the subfloor but different subfloors will react differently. A concrete floor as you say would act as a heat sink whereas a chipboard floor would be a reasonable partial insulator in its own right.
 
J

JimboD

Thanks All!

My take away is I'll use a 6mm insulation board (Marmox). It will add a tiny bit of insulation but more importantly prevent me from tiling on the chipboard. Key points:

  1. Insulation is a must on concrete to avoid it being a heat sink
  2. 6 or 10mm will have only a small insulation impact on a wooden floor
  3. 10mm wont improve the insulation properties much over 6mm
  4. Both can perform the important secondary role eliminating the need to tile on chipboard
 
U

Uheat - Keith

Lots of great information on all the above posts..

Our rule has always been:
Concrete bases - Ekoboard insulation boards if you have the depth Will help the underfloor heating. (or Construction boards) where tiles etc is the floor finish.
Wooden bases: We have always said that the maximum output on this type of floor is 100w/m2.
This is where the Construction boards come in - if you have the spare depth, put these down and you can then use a 160w/m2 mat, or a 200w/m2 mat, where tiles etc is the floor finish.
Warm regards,
 
J

JimboD

Colour Republic said:
HTW (Hampshire Tile Warehouse AKA The tile source) used to do them but not sure if they moved over to Obrey boards now?

Does it have to be Marmox?
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Funnily enough I did a google search and found a company by complete chance called The Tile Fix which had some in stock and are 15mins away and had a fair price. It turns out it's the same location as Tile Source. Not sure if it's one and the same but they seem to be aligned. Perhaps Source is the showroom side and Fix the materials side? Anyway, all sorted. Cheers!
 
J

jonnyc

well i think that some insulation is better than nothing and the thicker you can use the better.
i always use 12.5 mm contractor over timber substrate if i can.
but more importantly you need to think that an insulation board must be better than ditra mat over plywood which would let all heat through .
both ditra and dukkaboard or similar act as a separating membrane between tile and timber substrate.
 
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