Under floor heating

[bellyboy]

Hi all, Newbie here.
Im doing quite a few mods to my house over the next few months, Starting with a new bathroom first.
My question is, Is it an ideal idea to put under floor heating in the bathroom rather than having just a radiator on the wall. Its not a cold house, I was thinking more of a luxury. Is it expensive to run, Is it problematic? Any tips and tricks please.

Next question, Im going to be tiling the kitchen, Is it an ideal source of heating to be putting in there, I was toying with the idea of just putting a floor heater in one or two of the kick boards on the cupboards?
Let me know you're thoughts and experiences.

Regards.

 

[ban-all-sheds]

My question is, Is it an ideal idea to put under floor heating in the bathroom rather than having just a radiator on the wall.

Surely you'll have a heated towel rail?

Its not a cold house, I was thinking more of a luxury. Is it expensive to run,

It's a lot more expensive to run than slippers or a mat.

And hugely more expensive to install than either of those, especially legally.

Next question, Im going to be tiling the kitchen, Is it an ideal source of heating to be putting in there,

No.

It's rare for it to be an ideal source of heating anywhere, because it takes so long to heat up and to cool down, and because the output is often insufficient.

Also, do you have enough insulation in your floor? If not, are you prepared to excavate and re-lay, or to have a step up as you enter the kitchen?

I was toying with the idea of just putting a floor heater in one or two of the kick boards on the cupboards?

Sounds like a much better idea.

Don't forget to read this: //www.diynot.com/wiki/electrics:part-p

 

[jaysean1]

If you have central heating in your house I would not bother with under floor heating, just get a bigger radiator or get 2 radiators if need be.

In the kitchen we have a plinth htr with works with the boiler and blows out the hot air.

 

[ericmark]

I can only talk about the under floor heating I fitted in my mother's wet room. It was fitted to dry the floor as with her having only one leg we were worried about her slipping on a wet floor.

The floor was tiled with sculptured tiles again to afford more grip in hind sight a mistake.

Turning the under floor heating on it was just cool enough to walk on with bare feet. Any hotter and it would have been a problem. Yet without the towel rail on the room was too cold.

Once the shower was turned on the tiles cooled and after turning off again it took 15 minutes for the floor to heat up again and start drying. By which time my mother had finished and had left the room.

So in real terms a complete failure.

It did mean that soon after people could go in and use the loo with a dry floor but it did not do what we wanted.

As to fitting, the builder killed the first one and all tiles had to be lifted and a new one fitted. The thermostat sensor failed and it would not draw up the tube so could not be replaced. Using the room air part of the sensor soon after the thermostat failed. That has been replaced but seems has failed yet again. However it has been such a failure we have not bothered renewing it a second time.

So all in all the whole idea reminds me of chocolate fire guards.

 

[RF Lighting]

It's a really really expensive way of making your tiles so they are not cold to walk on, and that's it.

 

[ELZ4742]

you have to take into consideration wheather its primary or secondary heat..big price difference.
its a pain in the rear if the probes go down too, can be a nighmare to rectify.

 

[ban-all-sheds]

I know someone planning to build a house - serious undertaking - architect designed, 6-figure build cost.

He has UFH now.

Doesn't want it anywhere near his new house.

 

[cider]

i've got it in my kitchen and its the dogs bo llocks.
we've got 150w m2 which is a must for concrete floors.
No insulation below.
Max floor temp should only be 35c but it never has to get anything like that.
We have a proper controller with floor stat and air stat which anticipates on off times so its only on when needed and no other heating in that room.
Thats the plus side.


We've not had an electric meter reading since we moved in 5 years ago

Anything spilt or dropped on the floor gets welded on

Personally i think its great if sized correctly and fitted with correct controls.

 

[ELZ4742]

no insulation below? blimey, must act like a massive storage heater!

 

[ban-all-sheds]

It's where the term "global warming" comes from.

He's using his UFH to warm the globe.

 

[cider]

He's using his UFH to warm the globe.

Why do you think Australia is so hot

 

[ericmark]

Correctly designed I am sure it will stand the test of time.

The system shown was used during the Roman occupation of Chester and as seen is still there today. However one has to realise the building was designed from ground level to have under floor heating. It was not added as an after thought.

If you look at the thickness of the floor you must realise how much heat will be stored in the floor. It would be impossible to use any type of thermostatic control the only option would be to open a window.

Although the modern systems use a more controllable fuel source, the floor still holds the heat. So under floor heating is only good in a building used 24/7. It is impossible to turn off during the day while at work as it takes so long to warm up and cool down.

The system fitted in my mothers wet room took an hour to get floor hot it then has to heat room so really looking at least 2 hours warm up.

It is the speed of warm up and cool down that is so important in designing a system. A church will often use electric radiant heaters because they are near instant as they heat people not the air. So are only one while people are in the church. So although electric which is an expensive fuel for that job are cheap to run compared with other types.

In a house hot air is fastest system. The Myson radiators store very little water so since there is not as much water to heat up first they start heating quicker than normal radiator system. However there is a draw back. Control, the thermostat is built into the radiator and controls the fan so when the room is warm hot water is returned. With all Myson this is great but mixed with standard radiators it will turn the boiler down premature.

The standard radiator reduces water flow when hot enough and when nearly all radiators are hot enough the by-pass valve opens sending hot water back to boiler so reducing flame height then finally switching off.

So for a Myson to work with standard radiators it needs motorised valve so fan and water turn off together. This means on turn on the water has to be turned on first as the Myson is designed not to blow until water is hot. I have wondered if they could be paired with standard radiator so the standard radiator valve would control supply to both? However not tried it.

This is the system of blown air under the plinth. Again idea is great. But you really need some one who knows their stuff to fit it and set it up.

 

[stunlawless]

Morning Belly,

Like others said, don't even think about it for heating the room. I've got it in two bathrooms to warm the tiles so that it's not too cold for my wife's dainty feet, and dries the floor afterwards (c'mon RF, surely there's space for a little luxury in life ?). Control temp is set to 26 C.

I got mine from http://www.ambient-elec.co.uk . I'd recommend the "Professional Under Floor Cable Kit" - it comes with more and better stiff to fix the the cables to the floor, and two undertile temp sensors (one to be installed as a backup in case the first one fails) Both are in a duct so (in theory) can be replaced without lifting tiles.

Mats are fine for regular shaped rooms, but with floor mounted pans, quadrant showers and free standing baths, cable is more flexible. Usual rules about tiling floors apply, but with as much insulation under the tiles as possible. Marmox boards are quick & east to use, but of course all this can add up to a significant step in floor levels.

The Aube TH132F controller is good - easy to use and easy on the eye. It has a holiday mode which is useful for the guest bathroom. It's clever enough to keep the tile surface temp pretty constant, and I've got it set up for 2 hours in the morning for all the family, and an hour in the evening for the kids bath time.

All in all, I'm very pleased with the results. More importantly, so is my wife.

One tip: when you've laid out the cable, take some photo's with a ruler in shot. You never know when you'll need to drill the floor !

Hope this helps, David

 

[ericmark]

Remember for a bathroom the cable must be encapsulated inside some form of earth. Either special cable or a earthed mat over the heating wires. I had to write to manufacturers to be sure the type I used was suitable for bathrooms.

With hot water of course not a problem. There is an electric type that uses a chemical in the cable which stops over heating problems. Similar to Raychem used to stop pipes freezing. But this type did not have the earth required and so was unsuitable for bathroom.

 

[bernardgreen]

I have wondered if they could be paired with standard radiator so the standard radiator valve would control supply to both? However not tried it.

I installed a mixed system of radiators and blown air ( custom built units ) when we built this house in 1981. Each radiator has its own motorised valve and each water to air heat exchanger has a motorised valve and the fans are also switched. Each area (zone) served by a radiator or air system has its own thermostat to control valves and fans. Any zone demanding heat activates the boiler. It does mean the boiler would short cycle if only one zone was demanding but that was not apparently detrimental to the boiler.

The initial water to air unit were "off the shelf" units but they proved to be less effective than was claimed.

Plinth heaters

If possible use flexible pipe work to allow the unit to be pulled out from under the plinth for cleaning and servicing. Rigid pipework can mean dismantling work top and cabinets just to clean the fluff out of the heat exchanger. Ensure the flexibles are suitable for the highest water temperature the boiler might supply in a fault condition.