Electric underfloor heating

[Lesandpen]

Following on from the previous thread about wet underfloor heating, does anyone have any information about electric underfloor heating systems, how controllable and comfort levels etc.. I can't justify the installation cost of a wet system. it will be for a one storey new build property thanks.

Les

[philipbar]

Hello,

I can't give you any solid advice, because we have only just installed electric underfloor in France, and the electrician suggested we had not left enough depth for the top cement and tiles. We shall see.

I have, however, installed it in the UK. It is under a tiled floor of about 10 square metres in a conservatory. I bought Devimat, and the kit cost around £400 from an Internet site I cannot remember. Screwfix.com do an alternative make (which we have used in France), for about £50 less.

I used the matting, in which the heating elements are fixed to a mesh to keep them the correct distance apart. It is pretty easy to lay, and you can cust the mesh to get around obstacles. You must not buy a mat that is too large because you cannot (evidently) cut the elements.

I embedded it in self-levelling floor compound, and used about 5-8mm cement for the tiles above that. I have seen advice to use flexible cement, but I just used regular tile cement, and have had no problems to date.

I cannot say what it is costing yet, but the documentation with the kit suggests a few pence per day. It is the only heating that we have in the conservatory, and the windows are not double-glazed, but it keeps the place reasonably comfortable.

We will be turning the heating on in France in the next couple of months, I hope, and will discover then whether we have laid it correctly (we just embedded it in a layer of tile cement, then laid further cement and the tiles over that). The electrician's concern is that the elements are not deep enough, and that their heat may cause the cement to crack and the tiles to lift.

I hope this gives some useful points, but please write again if you have any specific queries.

Regards,

 

Philip

[Lewisra]

Hi Les.

We installed electric under tile heating in our dinning room and bathroom last summer. We used the wire only version (which was a fiddle) to lay in the bathroom. It is only controlled by a thermostat running off a probe in the floor. In the dinning room we laid a mat version controlled by a thermostat regulated by floor and air temperature. We have since found another manufacturer who makes a version of heating which is flat to lay, big bonus, look at www.aht-heating.com.

We used the heating in ernest at Christmas for the first time. It took three days to raise room temperature from 8c to 16c. We used no other heating in the rooms, I was aiming for 20c but we were not in the house long enough. We did not install any insulation over the concrete floor which could explain the long warm up time. Insulation costs are as high if not higher than the heating system. It does work and is very comfortable. The dinning room by the way is 40 square M and we only laid the heating wires in strips, we did not cover the whole floor. We also used flexible tile cement and grout.

Hope that helps.

Richard 

[derf]

Thanks to you both for your replies, our heating system will be laid by the builders but I don't know any details at the moment about which system they will be using, until we go into a little more detail when we give them the  go ahead to start the build, just interested in the comfort levels, time to warm up running costs etc. 

Thanks Les 

[Nick Trollope]

Hi

Whilst on this subject, can anyone offer any advice/recommendations for underfloor heating on a typical joists/wood plank floor, ie. installed from the floor below.

In my case, one floor is crappy chestnut  & will be carpeted and the other is a chestnut/pine/chipboard sandwich (and may have a laminate put on top of this lot!).