Empirical Info on floor covers and underfloor heating.
Discussion
Looking for actual data on floor coverings over underfloor heating. We were going to tile our newly poured boot room and kitchen floors, but it occurs to me that we could save cash by going laminate as I could lay it myself (also I genuinely prefer the feel underfoot). It really comes down to thermal performance - I know tile is the most efficient conductor of heat, but how much better is it? I can only find comparable data on floor coverings that lumps laminate in with engineered wood, which is completely different. Or I can get a value for laminate in ‘tog’ (like a duvet) and one for tile in W/m•k. Also tile and laminate come in different thicknesses. Any idea how I can get real info, not anecdotal?
To some extent, a less conductive floor covering just means the same power into the heating, but a higher slab temperature.
But in the detail, heat loss down into the ground starts to matter, so what's under your slab?
Also heat pump efficiency will be affected by a higher slab temp.
If the room is better insulated, then power is less, so delta T across the floor covering is less.
The wood and laminate floors I've dealt with, I think the thermal performance has been mostly driven by the underlay?
But in the detail, heat loss down into the ground starts to matter, so what's under your slab?
Also heat pump efficiency will be affected by a higher slab temp.
If the room is better insulated, then power is less, so delta T across the floor covering is less.
The wood and laminate floors I've dealt with, I think the thermal performance has been mostly driven by the underlay?
Thanks for the reply - not sure what a delta T is, but am intrigued.
Slab is concrete raft (so not deep) with 100mm PIR and 60mm anhydrous screed with UFH pipes in. Screed has been insulated all round with 25mm PIR. Currently looking a 11mm tile or Quickstep ‘Hydro’ laminate with their ‘Silentwalk’ underlay.
Slab is concrete raft (so not deep) with 100mm PIR and 60mm anhydrous screed with UFH pipes in. Screed has been insulated all round with 25mm PIR. Currently looking a 11mm tile or Quickstep ‘Hydro’ laminate with their ‘Silentwalk’ underlay.
Neither floor covering would act as an insulator and with 100mm PIR won't lose anything going down
I think performance will come down to the installation
15mm pipe at 100mm centres with max circuit length of 100m will give you roughly 100 Watts per m2 at flowtemp of 50 degree, which is roughly the max you can get of the system
What's your installation?
I think performance will come down to the installation
15mm pipe at 100mm centres with max circuit length of 100m will give you roughly 100 Watts per m2 at flowtemp of 50 degree, which is roughly the max you can get of the system
What's your installation?
The building itself is timber SIPS style panels, internally lined with Actis multifoil, triple glazed throughout. The UFH is 16mm (I seem to remember it was annoyingly different from normal plumbing) at 150mm spacing. I believe the laminate I was looking at specified a max temperature of 28°. We will eventually be running it from an Air Source Heat Pump.
I am really appreciative of the input, but am still surprised there is no go-to chart of relative thermal performance of floor coverings…
I am really appreciative of the input, but am still surprised there is no go-to chart of relative thermal performance of floor coverings…
We have under floor heating with marble floors.
The house is very well insulated so the hall in practice heats the whole house all winter.
We wear slippers inside so don't notice but the unheated floors are cold under foot. Laminate will be warmer.
With under floor heating conductivity is one part of the equation and thermal mass is the other. The concrete in the floor is a mass and in my case so are the tiles. The mass enables it to store heat and give a consistent room temp.
The laminate will have less mass and store less heat.
For carpets we use low tog carpet and underlay so the heat can get through but the benefit is this is moot as the hall heats the whole house to 22 degrees and the carpeted floors are never on.
This does not directly answer your question but there is more to it than just the insulating properties.
In our last house we had engineered wood floors across the ground floor and there was no noticeable difference in the systems performance over tile once the whole thing has stabilised which takes some hours so the floor and sub floor are at the same temp.
I would get what you want. Either will work
The house is very well insulated so the hall in practice heats the whole house all winter.
We wear slippers inside so don't notice but the unheated floors are cold under foot. Laminate will be warmer.
With under floor heating conductivity is one part of the equation and thermal mass is the other. The concrete in the floor is a mass and in my case so are the tiles. The mass enables it to store heat and give a consistent room temp.
The laminate will have less mass and store less heat.
For carpets we use low tog carpet and underlay so the heat can get through but the benefit is this is moot as the hall heats the whole house to 22 degrees and the carpeted floors are never on.
This does not directly answer your question but there is more to it than just the insulating properties.
In our last house we had engineered wood floors across the ground floor and there was no noticeable difference in the systems performance over tile once the whole thing has stabilised which takes some hours so the floor and sub floor are at the same temp.
I would get what you want. Either will work
Aerate said:
The building itself is timber SIPS style panels, internally lined with Actis multifoil, triple glazed throughout. The UFH is 16mm (I seem to remember it was annoyingly different from normal plumbing) at 150mm spacing. I believe the laminate I was looking at specified a max temperature of 28°. We will eventually be running it from an Air Source Heat Pump.
I am really appreciative of the input, but am still surprised there is no go-to chart of relative thermal performance of floor coverings…
So the building is well insulated.I am really appreciative of the input, but am still surprised there is no go-to chart of relative thermal performance of floor coverings…
You should have a figure for the heat loss of each room in watts when it's say zero degC outdoors and he room is say 20.
From that you can see the watts per sqm you need from the floor.
A floor covering will have a thermal resistance in degc or K per ( watt per sqm ). A typical value for carpet is 0.2, so if you need 100W per sqm to keep the room warm, your carpet would have a 'delta T' of 20 degrees, i.e. it would have the slab 20degrees warmer than the top of the carpet. So your water flow temp would be something like 45degC?
There's a 'consumer' unit of thermal insulation 'tog'. 10 tog is 1 K/(W/sqm), so a typical carpet is about 2 tog.
Laminate floor might be about 0.7 tog, plus about 0.3tog for an underlay intended for UFH. so about 1 tog.
Ceramic tile or thin plastic vinyl, bugger all.
https://www.uponor.com/en-gb/best-floor-coverings-...
A well insulated room without huge windows or multiple outside walls probably needs a lot less than 100W per sqm. Most of the time it's not zero outside, so the heat loss is even less.
Big areas of glass and lots of heat escaping upstairs can seriously up the demand on UFH though. As can a location facing some weather.
My brother's house has UFH with a carpet in the lounge and some kind of tiled floor in the kitchen diner, which has a patio door and stair coming from it, that kind of works now it's balanced.
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