Electric towel rail swap to underfloor...?

In Chester my closest city we have examples of underfloor heating installed by the Romans, however after the Romans left the UK it seems we stopped using it, now I know why, it's useless.
Playing devil's advocate here ...
Perhaps we didn't learn from the Romans how to put in properly specced systems and operate it correctly !
For the failure you describe, the very first thing that stands out is that the heat input power (you didn't state the heater power) is insufficient for the thermal mass and intended mode of operation - ie it's not the system that's "not working", but the system is working as best it can given that it's not been correctly specified. Something specced for the required mode of operation wouldn't take 4 hours to heat up.

So I'd say that your post is along the lines of "electric lighting is crap because I struggle to read using the 25W bulb I put in the pendant holder" :whistle:
 
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I've seen hypocausts. Looking at the floor area, made of brick and tile, with mosaic, and the small fire-hole that a slave would have been poking chopped wood into, there's no way it could have done more than take the chill off the floor nearest the "hearth".

I'll guess it was a building technique that might have been useful in central or southern Italy.
 
I've seen hypocausts. Looking at the floor area, made of brick and tile, with mosaic, and the small fire-hole that a slave would have been poking chopped wood into, there's no way it could have done more than take the chill off the floor nearest the "hearth".
I must say that I thought it was more clever than that, with the 'flues' from the fire routed through the underfloor space, so that there was a considerable flow of hot air to most/all parts of the floor (a bit like some some large-scale kilns, or even the 'fire tubes' in the boiler of a steam engine).

Kind Regards, John
 
flagged concrete floor was raised on tile-brick pillars, with fire-holes on the windward side to draw the hot air and fumes around the void under the floor.

Not unlike the way airbricks are used under a suspended floor to cause airflow.

There was a great deal of masonry to heat, and rather small fire-holes
 
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flagged concrete floor was raised on tile-brick pillars, with fire-holes on the windward side to draw the hot air and fumes around the void under the floor. Not unlike the way airbricks are used under a suspended floor to cause airflow.
That's roughly what I was trying to describe :)
There was a great deal of masonry to heat, and rather small fire-holes
True, but if it were heated continuously (I don't know, but I presume they had a plentiful supply of slaves), I would have thought that that masonry would eventually get quite hot, and then would stay hot for a long time.

Kind Regards, John
 
The major problem with a bathroom is today we have a lied down air flow and a limit to the floor temperature, so for it to stay warm enough the replacement air must be heated, so the major question is where is the replacement air drawn from? In mothers case it was from the hall, which tends to be cooler than the rooms. So with a bath or shower room accessed from the bed room then the replacement air may be warm enough.

So with a wet room the max temp of floor is 33°C since it is a wet room you want the air at around 25°C that's just 8°C differential between floor and air at 15 litres air a minute the incoming air would need to be 23°C at least which is rather hot for other rooms in the house.

The rules and regulations were not in force in the days of the Romans so their system may have worked. But using a heat recovery unit with a heat drop of just 5°C would still leave the room cold, OK an bathroom floor can be a little warmer than a wet room floor, maybe you can use the full 55°C, however use Vinyl flooring and your down to 27°C.

It really does not matter how big the heater under the floor is, when the temperature has to be limited to such a low value it simply will not heat the room.
 
You missed the point.
You complain about the time it takes to heat the floor - air-flow and allowable temperatures have nothing to do with that. A more powerful heater would heat the floor faster - that's simple physics - and would then get switched off by the stat somewhat sooner.
Pre-empting the next retort - there may well be limits in terms of "what temperature will the floor reach if the stat fails" which will limit the power of an electric system. But with a wet system, there is a built in fundamental limit in that the floor cannot get hotter than the water supply. It's getting off-topic somewhat, but I still maintain that the bulk of your gripe is that "we didn't spec it right and it doesn't work very well".

I take the point about heating the room - and I don't argue against that. I'd love UFH as a comfort factor (as I write this, my toes are cold but the rest of me is warm enough), but I'd have radiators for the main heating as well as the speed of response. It'll be interesting to see how mum fares in her new house with an unheated concrete slab for the ground floor ... according to the vendor it'll be nice and warm as there's 6" of insulation under the slab :oops:
 
You are correct, the floor was dug out down to the drains level and filled back in with insulating material, so even without under floor heating the floor is not cold, the base before the heating wires is plywood, so there is a limit to how hot one can allow the heating wires to go, we followed the manufactures recommendations, and left on the heaters will cycle with less than 50% on and 50% off time to keep tiles at the recommended maximum of 33°C. If left the floor would get a lot hotter. I would say the floor is likely around 60°C now the sensor under the floor has failed within the two hours I switch on the floor before mother goes for a shower.

The tiles are quite good at heat transfer, but they also have a high storage capacity, once heated without water on them they take a long time to cool down, but the water quickly cools them down, and it's another hour before they are dry again, mop the kitchen floor with quarry tiles and no under floor heating and it is dry quicker than the wet room with impervious to water sculptured tiles (to give more grip) as the water in kitchen naturally sinks through the tiles.

The main reason for the underfloor heating was to dry the tiles after a shower rather than warm ones toes, if I forget now the sensor has failed you can't walk on the floor with bare feet, but unless the towel rail is on, the room is cold, even when the fan is off.

It is without question the biggest waste of time and money of any project I have been involved in. It does not heat the room, it does not dry the floor, and my mother does not keep her toes warm as sitting in a wheel chair and only has 5 toes anyway. It has been totally useless. I do still use it to dry the floor, it is switched on for mother on days she has a shower so when she returns to room to use toilet the floor is dry. In hind sight the sculptured tiles was a mistake smooth tiles would have allowed the water to run off better, but all that means is I have to brush excess water off tiles once she has finished, still takes an hour to dry.

My sister would not allow me and my son to do the wet room, she said we never finished a job, so the planning was left to a bathroom specialist, it was a total failure, in the end we did have to take over, the design of enclosed loo means it's too low, it is also too close to wall, that we could not change when we took over drains in and loo bought, they also moved door way without moving lintel so one end of lintel unsupported, used out of date tile cement which would not set, fitted a extract fan with no access to replace, the old one is still sitting there can't remove it now ceiling plastered. The list goes on.

Under floor heating is a major task, the hot water type is self regulating and there is something like the RayChem trace heating which is to an extent self regulating with electric under floor heating, but at the time when mothers was laid this type did not have an earthed mesh around the heating wire, so to use with a bathroom it would need a copper mesh laying over the heating wires before the tiles are laid, this would be very expensive.
 
... so the planning was left to a bathroom specialist, it was a total failure
You have my sympathies on that.
And from what you describe, there was the opportunity to fit a wet system that would have been quicker to warm up, cheaper to run, and safer - I guess that's what the "professionals" are for eh :rolleyes:

In my Mum's new house, the vendor was saying how the floor won't be cold because there's 6" of insulation under the concrete slab - yeah right. This same house doesn't have a supply for a "proper" cooker - the assumption is that you WILL use gas and so there's only a double socket off the ring for the ignitors etc. ****ing cheapskates about sums up various aspects of the fit out.
 
In my Mum's new house, the vendor was saying how the floor won't be cold because there's 6" of insulation under the concrete slab - yeah right. This same house doesn't have a supply for a "proper" cooker - the assumption is that you WILL use gas and so there's only a double socket off the ring for the ignitors etc. ****ing cheapskates about sums up various aspects of the fit out.
I would agree, however to be fair the electric hob has only in the last 10 years become better than gas. Today I am sure if some one invented the gas cooker they would be told no way that's not safe. But it's down to what one is use to, after getting use to an induction hob and an oven with 12 options on how it is heated, when going in the caravan or mothers house it is so easy to make errors, we expect the hob to auto close down as the pan is removed, and to auto start up again if returned to hob within a short time, but lock out if removed for long time, we expect to be able to wipe clean as we go without the kitchen role paper going on fire.

I would use gas central heating but would not consider gas cooking other than when camping out. Even the range cooker does not have naked flames, although for them you need quarry tiled floors so in an emergency you can rake out the fire.

Insulation has a major problem, water. As long as dry the insulation works well, but get it wet and it's useless, it can also absorb the liquid so one is unaware of the problem for years. We had a leak on the roof, when corrected it was found to be due to a tile being cut wrong, so it was there from when first built, but took 10 years before we found we had a leak.

Yes wet underfloor heating does work better, but that is also slow, my son has it to sink the heat from range cooker so the water will not boil, and with a range cooker you don't light it for 1/2 hour to cook then turn off, it runs all day and night, so the heating is never off, at least in the winter, working out how long it takes to warm up is hard, as never off, the gas central heating adds to it to maintain the heat at the set level. The problem is in the summer, the whole house gets too hot.

I have fitted an induction hob, and use stand alone pressure cooker, LED lights, and fluorescent tubes not just to save energy but to keep house cool in the summer. The idea of first thing in the morning having to decide if we will want heating that evening is to me daft, even worse is working out the night before what off peak power you want.

Windows are also a problem, Oh the K glass is wrong way around they said, but was it, it was fitted so the room did not get too hot in the summer, I don't use radiant heaters so heat will not escape through the double glazed window, the allowing radiant heat to escape but not enter the house was right way around to my mine, but the window guy tells me it is designed to make out house into a green house in the summer!

The problem is a house should be viewed as a whole, not each item on it's own, may be if I had North facing windows the glass should be the other way around. I have made many mistakes, Myson radiator for example, small, fast to heat room, water can be hotter as no exposed hot metal parts seems great, but as soon as it turns off room starts to get cold, hard to integrate with condensing boiler, and you have to turn up TV volume every time it kicks in. In the kitchen would be A1, also good in bathroom as circulates the air drying the room out, and fast to react.

In real terms every room in the house has likely different temperatures and speeds required for the heating, this is why Nest and Hive are not suitable for most British houses as they only sense the temperature in one room. But Evohome costs a fortune. So we muddle on with a hotchpotch system with loads of faults, but it works near enough for what we want.
 
The problem is a house should be viewed as a whole, not each item on it's own
I think there's a bit of both. Yes, each room has it's own requirements (cf the comments on Mysons in bathroom and kitchen) - but then different things interact with (typically) one source of heat.

Myson radiator for example, small, fast to heat room, water can be hotter as no exposed hot metal parts seems great, but as soon as it turns off room starts to get cold, hard to integrate with condensing boiler, and you have to turn up TV volume every time it kicks in.
Yes, they are great little things for getting heat out quickly - but as you say, like all warm air systems, things cool down fairly quickly once they go off (same problem in Church where they (different make, bigger) are too noisy to leave on during a service). Had a load in the offices where I used to work.

On condensing boiler integration, are you using them as per the instructions - constant flow and turn the fan on/off with the thermostat ?
If so, then I have a suggestion to deal with that ...

In real terms every room in the house has likely different temperatures and speeds required for the heating, this is why Nest and Hive are not suitable for most British houses as they only sense the temperature in one room.
Indeed.
But Evohome costs a fortune.
OpenTRV are starting to get a few units available if you're into tinkering https://myradbot.com/product-category/engineering-samples/
TRV heads are in very short supply, getting added to stock as someone has time to test what's lying around !
 

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