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

[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.

 

[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]

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.

"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

 

[Ajax123]

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

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.

 

[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

 

[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,