Underfloor heating

[AudiPartner]

Need to pull my finger out and get things ready for the new arrival in July. Saldy it's not a new Porsche, but a child.

Our new central heating isn't brilliant as we're running a combi boiler in an old house with a one pipe system. It's adequate, just not great. And the bedroom we have chosen for the nursery doesn't get all that warm at all. We are carpeting in there (wood at the moment) so as a quick fix I am consider under floor heating. The room is only small, about 7 x 7.

I know nothing about underfloor heating, and didn't even know whether you could have it under carpet but apparently you can, provided the combined "toggage" of the carpet and underlay is less than 2. But I know nothing else about it - for isntance how do you power it? Just plug it in to the wall?? Presumably you can have a programmer and thermostat much like a conventional system? Do you fit it under across the whole room, or just the middle, or just the edges? etc etc!

ta

[cruiser647]

Congrats on the new arrival! lol at the 'sadly is not a Porsche' comment!

However, underfloor heating is fine. You get a wall mounted switch and thermostat which you can set for electric based systems. Some systems use pipes and plug into your rad pipes, but you are then restricted to having the heating on - and as yours isn't great........ it'd be a waste of time.

However, what about a replacement boiler instead? Would probably save you more in the long run.

Unferfloor heating can very expensive to run and unless you have a timer, can be easily left on all night and all day.......

Carpet wise, you can get higher 'tog' rated carpets too. They'll help keep the room warmer.

[AudiPartner]

Thanks Cruiser.

The boiler is brand new! Swapped from oil to gas. The problem is the one pipe system apparently so the answer is to renew the entire central heating network. No ta!

[Calm Chris]

There's 2 types- wet (water via CH) and dry (electric).

Heat wise dry costs 3 x more than wet. As a bedroom solution it will be absolute rubbish.

I'd suggest you have had poor advice regarding the CH system. There's no such thing as 1 pipe, all ch works on flow and return. and hence one pipe out and one pipe back.

Get another plumber and ask them to do a 2 hour review, get them to bring the balancing kits (two temperature gauges) and set up the rads, thermostat and system correctly. It sounds like your pump might not be circulating the ch correctly, maybe a non return valve has failed.

[Booster]

Your house is old isn't it? I presume that there won't be a cavity so you can't have cavity wall insulation. This was a problem that we had with our house. My youngest's bedroom has three external walls and we had insulated plasterboards fitted and it is now the warmest room in the house! Might be worth looking into?

[AudiPartner]

My youngest's bedroom has three external walls and we had insulated plasterboards fitted and it is now the warmest room in the house! Might be worth looking into?

Now there's an idea. Yes, old house.

Ok, perhaps I'll get a local boy round to carry out review.

[Booster]

This is the stuff we used:

Kingspan Insulation - Kingspan Insulation - Kooltherm K17 Insulated Plasterboard

I got a chippie to come in and remove all the skirting boards, picture rails etc. Plasterer came in and fitted the boards, chippie came back to refit everything he took off and extend window sills. Job done!

[Tipex]

I looked into underfloor heating for our house, but when you weigh up the costs of running it, it's just too expensive, shame really as I'd love to het rid of the radiators.

[AudiPartner]

This is the stuff we used:

Kingspan Insulation - Kingspan Insulation - Kooltherm K17 Insulated Plasterboard

I got a chippie to come in and remove all the skirting boards, picture rails etc. Plasterer came in and fitted the boards, chippie came back to refit everything he took off and extend window sills. Job done!

Watch my 7ft room become a 6ft room... though that will make it even warmer!!!

In all seriousness, will give it some thought. I still like the idea of under floor heating - why would it be useless in a bedroom Chris?

[cruiser647]

shame really as I'd love to get rid of the radiators.

Yep! would be nice!!!

[Daz]

I'd suggest you have had poor advice regarding the CH system. There's no such thing as 1 pipe, all ch works on flow and return. and hence one pipe out and one pipe back.

I think you'll find there are single pipe systems about, it does exist. Not very efficient but it is out there.

http://www.centralheating.org.uk/Central_Heating/single_pipe_system.htm

[Daz]

And I'd avoid UFH in a bedroom too. It's not efficient under carpet, electric is very expensive to run and pipe is tricky to install over/under floorboards and really needs to be on a separate circuit to your radiators

[m4ttm4son]

I'd say your best solution would be to insulate the room as already suggested.

Electric underfloor heating is ok for a bathroom which you switch on for an hour or so in the morning in winter, but I wouldn't want it anywhere I actually wanted to keep warm for very long. It costs a fortune to run, like any electric heating.

Wet underfloor heating is the boll0cks and something I will definitely be doing in this or the next house. It costs a few quid to install properly, but once down it should never leak or need maintenance. Except for the boiler and pumps which can go, obviously. Running costs are cheaper than rads too. But you wouldn't want to do all this for just one room, either.

Have you had your rads power-flushed? If they're full of gunk they will be inefficient and you'll be killing your new boiler too.

[scillyisles]

Hmm quite a lot of incorrect information here.

Firstly, wet underfloor heating is no more expensive than radiators and in most cases is less expensive. Wet underfloor heating works at a lower temperature than radiators and produces a much more even and comfortable warmth. Once you have had underfloor heating you won't want to go back to radiator central heating.

Secondly, wet underfloor heating can be combined with radiators. Typcially the underfloor heating operates via a temperature reducing manifold whilst the radiators such as towel rads in bathrooms operates at a higher temp.

Generally most wet floor systems installed at housebuild have individual thermostats to each room and individual microvalves to control the flow to each room giving you great flexibility.

The only real downside with underfloor is response time from cold - e.g. when you come back from holiday and the central heating is off. It takes time to bring the system up to temp.

Electric underfloor heating is much more expensive to run and best used in say afterbuild when you cannot start digging the floor up to install pipes.

Edited March 4, 2013 by scillyisles

[garcon magnifique]

I have electrical underfloor heating in my upstairs wetroom, because I love to live dangerously.

[Calm Chris]

Thanks for that Daz, I can't being to guess at the age of a single pipe ch system, since all I've ever worked on has been pumped flow and returns.

I'd guess the balancing of the valves is critical to avoid a huge temp range between 1st and last rad, I'd also imagine pump power is critical since the rads should be more restricted at the 1st than the last and the hw will need pushing along a bit more than standard system.

Wet under floor is good, but in needs an empty property and a full fit. I'd imagine insulation layer, pipes and clips, over cover and then the floor would lift the floor level 60mm and just be daft.

Electric would do but at x3 the ch btu cost would be expensive to run.

I'd double check the existing system via a plumbers visit, and get them to tune up what you have, might a larger (or just new rad if the existing is old) not be the more simple solution?

The reason I hate electric is that the stat probes fail, and under a tiled floor

that is very bad news. I guess under a suitable soft floor covering servicing might be better.

When you look at the system for uf elect mats

http://floorheatingonline.com/shop/product/30/laminate-carpet-underfloor-heating-kit

£240 odd, over a 12mm insulation, then the electric mat, then board (or cheap laminate), then underlay and carpet, that adds up to 35mm above existing floor for a product that will have heat in the floor, and little in the room air.

Edited March 4, 2013 by Chri5

[garcon magnifique]

The reason I hate electric is that the stat probes fail, and under a tiled floor that is very bad news. I guess under a suitable soft floor covering servicing might be better.

I'm kinda consigned to the knowledge that one day that will happen and I'll have a useless underfloorheating control box on the wall. But it was a cheap option so no great loss - it'd be nice if it lasts until I've sold the house...

[Calm Chris]

Lets hope the more recent floor probes are better than some of the older units, few seem to get more than 10 years service life out of them,

[AudiPartner]

I'll do a bit of digging and see what I have on offer in my local area and see what they claim to be able to do.

If I'm running a combi, do I have a pump?

[Calm Chris]

I'll do a bit of digging and see what I have on offer in my local area and see what they claim to be able to do.

If I'm running a combi, do I have a pump?

Sure do, it will be inside the combi. You should have the installation manual with the boiler docs, normally the factory settings are left as factory- but a decent plumber with knowledge on the boiler should tune to suit the client use, pipe system, rad volume etc.

please don take this the wrong way, but you sound quite vague about the new boiler have you made sure the user settings are as you want them. Have you re- pressurised the system recently (loop fill and check the bar gauge)?

[AudiPartner]

please don take this the wrong way, but you sound quite vague about the new boiler have you made sure the user settings are as you want them. Have you re- pressurised the system recently (loop fill and check the bar gauge)?

Of course I'm vague - I do cars and printers! Lol, that's fine.

Perhaps not no... I keep on top of the pressuring ok and I know how to adjust the target flow rate, but that's about it! The boiler I have is a Vaillant EcoTech Plus 837. Any help or advice Chris is always appreciated.

[m4ttm4son]

That's a good 'un. We put those in our larger flats. Is it the one with knobs for adjusting temperature, or buttons and a menu system?

[Calm Chris]

I use the same boiler but the traditional open vent version.

That's quite a decent sized unit, so the boiler isn't the problem. I've done some reading up and basically one pipe systems are shite with a capital S.

The trick seems to be the elusive balancing that is required to push enough decent temp hot water around all rads. So on installation swept bends are used in various angles to achieve best water flow to all rads, then there's opening and near closing rad valves again to stop the first few being greedy. Add in TRVs and it all Becomes a mare.

The forums are full of plumber woes and single pipe flow, but getting it right is achievable. I'd approach a plumber who has experience both with the boiler and the one pipe system.

Apparently modern boilers look at the temp out and then back in, and there's various tolerances that fire the system and others that don't. With one pipe it sends these sensors bonkers and the call to fire (and thus heat) are so reduced that the system with a target water temp of 75, can take hours and hours to achieve.

I would assume the pipe works and the rads are clean and silt free? Did you have some sort of pipe cleaning process pre the new boiler?

[AudiPartner]

I forget now exactly what was done, but the guy said he didn't power flush for some reason (I think relating to the old pipe system). I had a few rads replaced and also some trv's!!

[Luke]

The hardest part of all this is actually finding a plumber who can be bothered to call you back.