Underfloor heating (electric matting type)

[Colin Wilson]

We're currently looking at redoing the bathroom from scratch - those with long memories might remember my questions about how to box in pipework a while ago, well, it didn't happen, it just got worse...

Anyway...

It's on the ground floor, solid concrete floor, and is part of a simple ground floor extension that connects to the rest of the house via a an ante-space (just wide enough to fit a tumble dryer in, to fulfil the old requirement of having two doors between a bathroom and a kitchen.

Raising the floor level an inch or two to insulate prior to laying the UFH and tiling might be a little restrictive - so the question is, just how inefficient would UFH on bare concrete be ? (would you even notice it was installed ?)

[Andy Burns]

I installed heating elements under kitchen tiles on an un-insulated convrete kitchen floor and it's very easy to notice the warmth on bare feet when it's used.

[David Hansen]

On Sun, 17 Feb 2008 11:45:09 -0000 someone who may be Colin Wilson wrote this:-

I hope you would notice the increased electricity consumption. Why try and heat the ground?

Is there any reason to want underfloor heating in the room?

[Colin Wilson]

Not too much of an issue on that score, it's only something like

60W/sq meter IIRC - i've had two PCs running 24/7 since about 1995, so a little more isn't going to make too much of a difference.

...building layers of insulation into it would create a step from the kitchen to the ante-space, and with having a fitted kitchen, it would be hard to rejig that to accomodate insulation.

It's the bathroom It's got a solid floor It's in an extension, ergo a little colder than the rest of the house

Last but not least, the missus has always wanted it...

[That Bloke]

Same problem here, I put in 8mm of insulation. I wanted to put in 50 to 75mm but floor levels would not allow this.

It takes around an hour and a half to realy notice that the heating is on if you are in bare feet. We have a downstairs bedroom with on suite and a little hall to the back door all with ceramic tiles with the electric mat under tile heating.

We only use the shower room when guests are here and only switch it on at those times. In saying that when it is on, it is lovely if you are walking on bare feet. If we could not use the stairs and were using the downstairs bedroom and on suite, I would have the tile heating on no question at all.

[Colin Wilson]

Thanks for that, much appreciated - at least it gives me an idea of how long it takes to warm up under semi-insulated conditions :-)

(we'd probably just end up leaving ours on full time fwiw)

[robert]

I have electric underfloor heating in 2 bathrooms - both tile on ply.

150W per sq metre, takes about 30mins/1hr to notice the difference, but with a thermostat timer very manageable. The heat does not spread sideways through the tiles , so make sure you cover everywhere you might stand with the mat - I didnt !

Only adds about 5mm to the thickness of the floor.

[That Bloke]

Thats a point. I left a good clearance round the WC and when you stand there having a Pee in bare feet you are standing on colder tiles. So work out where the WC is going and in that area disasemmble a bit of the mat and get the wirse to within 25 mm of where the wc goes. It will make a differance!!!!!

[robert]

Further investigation this morning suggests the heat spreads sideways across a tile reasonably well but not to adjacent tiles across the grout.