Underfloor heating power

[Goku]

Fair enough.

Well, that total (4,590 W) is just about within the capabilities of a 20A circuit (and well within the capabilities of a 25A one), which could probably be fed with 2.5mm² cable.

Not 'required' by anything, as far as I am aware, but would make very good sense, in case a fault were to develop in one of mats.

More generally,I do agree with those who are questioning the wisdom (both in terms of effectiveness and running cost) of trying to heat a loft (or anything, come to that!) with UFH. How is the rest of the house heated?

Kind Regards, John

That is perfect, thank you. The replies here have been very useful in helping me to ensure that I'm not solely relying on UFH to heat the rooms (which looked like it was going to be the case in the bedroom which only had 1 radiator planned); I have planned in a second radiator into the bedroom as a result

I will probably still install the UFH as a backup, but rely on the central heating and insulation to heat the rooms. From past experience, I will rely on UFH in the tiled bathroom to keep the tiles warm - having the bathroom heated in the process will just be a bonus

The house is heated with a Central Heating system via a system boiler. The entire loft will have new celotext insulation and triple glazed windows (with the exception of the existing roof windows which are double glazed).

Did the wiring diagram raise any concerns? Would there be a better way to provide power to the mats? Although it's not required, I will take a look into having isolator switches for each stat to be able to disable the UFH independently per room as you suggested - the alternative would be that the main fuse has to be switched off and the wiring to the faulty UFH disconnected before the fuse can be switched back on.

 

[ebee]

John, I suspect the ELFI is having a friendly game of soccer with you. Using terms loosely in the gen conversion gets us to inadvertently get things slightly technically wrong in some instances. I think ELFI has picked this one to kick the ball into the long grass.
An RCD is any number of devices which contain an RCD - such as an RCCB or an RCBO for example. An RCCB gen has "two slots" needed and an RCBO only one. Both are RCDs of some type.
I suppose he might be said to be the same as me with the "Bulbs and Lamps" thingy.

 

[Murdochcat]

OP if you do fit electric UFH in the bathroom just make sure you have an easy to use controller as leaving them on 24 x 7 becomes expensive to

 

[ericmark]

The wet room was not that large, but UFH covered it all including under shower tray and toilet, wall hung, it was an old pantry and coal house/outside loo knocked into one, just big enough for the wheel chair to manure, the door was a sliding type, so no real seal, and entrance was into the hall, main problem is hall was kept cool, so replacement air was also cool.

LABC insisted a fan was fitted, we fitted the smallest the regulations would allow, and once the inspector had walked out the door is was seldom turned one, and went through pipes in ceiling space so not great draft when turned off.

Mother would be taken for a shower in the morning, I tried getting up at 6 am and turning on the floor tiled so warm for her at 9 am, it was not warm enough, so had to turn it one as we went to bed. The cost was not an issue, she had enough money, the issue was it did not do what it was designed to do, and dry the floor after a shower so she could use the loo safely, once the shower had cooled the floor, yes hot shower cooled floor, but it would take 1.5 hours to re-warm it. It had not been turned off, just cooled by shower, so we had to mop the floor for it to dry in a reasonable time.

I would have preferred something like Raychem which does not require a pocket for the floor thermostat, it can't over heat, it self regulates, however it did not come with an earth braid built in, and under a wet room really needed the earth braid. Things have moved on, and now you can get versions which can be used in bathroom and wet room.

 

[JohnW2]

John, I suspect the ELFI is having a friendly game of soccer with you. Using terms loosely in the gen conversion gets us to inadvertently get things slightly technically wrong in some instances. I think ELFI has picked this one to kick the ball into the long grass.

Well, yes,I assumed that is was some sort of fairly extreme 'pedanticism',particularly given that my initial comment had started with "Most,if not all,..."

An RCD is any number of devices which contain an RCD - such as an RCCB or an RCBO for example. An RCCB gen has "two slots" needed and an RCBO only one. Both are RCDs of some type.

I realise that, which is why I subsequently asked him ...

Do you not at least agree that 'most' RCDs (RCCBs, not RCBOs) occupy 'two slots'?

... but, again,and despite my "most", he didn't seem to agree with even that, since his response (not really 'an answer' to my question) was:

Really?

I really do think that, in this case,my initial comment to the OP was, in context, totally appropriate (and he thansed me for 'the reminder') and that EFLI's intervention was at risk of confusing the situation, and the OP.

Kind Regards, John

 

[ericmark]

I am lucky, one of my TRV heads actually shows a report this is today, it shows how the temperature dropped from midnight until heating turned on, and then how it recovered, the hysteresis is because I use oil for heating so boiler does not modulate, however you can see the cooling curve well, and how important it is to running costs to turn off heating when room not used, and also how important recovery time is.

If you have to turn on the heating earlier to get the room heated in time, it will cost more, ideal is likely fan assisted radiators, but noise of fan, and cost mean in the main we use radiators with TRV controls.

 

[JohnW2]

IIf you have to turn on the heating earlier to get the room heated in time, it will cost more, ideal is likely fan assisted radiators, but noise of fan, and cost mean in the main we use radiators with TRV controls.

In thee real world,that will inevitably be true to some extent, but the extent does depend upon how well'insulated;' the room(and house) is.

If the room were 'perfectly insulated' (no heat loss to anywhere else), then the Laws of Physics dictate that it would take the same amount of energy to increase the temperature of the room by a given amount no matter how long it took to achieve that.

Kind Regards, John

 

[EFLImpudence]

I meant what I wrote, because I believed it.

Does that mean you no longer believe it?

Do you not at least agree that 'most' RCDs (RCCBs, not RCBOs) occupy 'two slots'?

Do you not at least agree that 'most' RCDs (RCBOs, not RCCBs) occupy 'one slot'?

So how many slots does an RCD occupy?

 

[JohnW2]

Does that mean you no longer believe it?

In terms of the original context, I still believe it. The OP had expressed a desire to add an "RCD" if he could, but accepted that he might have to resort to using RCBOs if there weren't enough slots (see post #1). He therefore clearly was (as very many people do) using "RCD" to refer to RCCBs, to the exclusion of RCBOs.

The banter between us about 'strict' (sometimes 'pedantic') issues of terminology/semantics are all very well, and can be fun at times, but you usually stop short of posting things that could confuse an OP, and/or other DIYers reading the thread. However, on this occasion I think you may have 'stepped over that line'.

It's not just DIYers who use terminology in the way the OP did. Very many, probably most, electrical wholesalers and retailers describe and sell RCCBs as "RCDs" (and RCBOs as RCBOs). In fact, I don't think that (m)any describe any of their products intended for domestic use as "RCCBs", do they?

Do you not at least agree that 'most' RCDs (RCBOs, not RCCBs) occupy 'one slot'?

You are again talking generally (and about terminology/semantics), not in the context of the OP or his thread.

Anyway, what you suggest would only be true if "most" of the RCDs in service were RCBOs, rather than RCCBs - and I doubt that that is yet the case, is it?

 

[EFLImpudence]

Do you mean "Yes, I'm sorry; I should have used "RCCB" in my original reply"?

 

[ebee]

Oh Dear, common lads!
We all know what wholesalers meant by "17th Edition Consumer Units" but we all know the there aint no such animal

 

[JohnW2]

Do you mean "Yes, I'm sorry; I should have used "RCCB" in my original reply"?

The banter between us about 'strict' (sometimes 'pedantic') issues of terminology/semantics are all very well, and can be fun at times, but you usually stop short of posting things that could confuse an OP, and/or other DIYers reading the thread. However, on this occasion I think you may have 'stepped over that line'.

" I'm out "