Would you replace your radiators with underfloor heating?

by , Researcher Energy & Home 29 September 2013
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Autumn is upon us and it’s hard to avoid looking towards the colder months and thinking about staying warm. Is underfloor heating the key to a cosy winter? Is it worth the cost and upheaval?

Underfloor heating

I’m a bit of a gloomy guts when it gets to this time of the year. Even the occasional sunny day can’t distract me from the fact that it’s getting dark earlier and the countdown to winter has begun. I can’t help my mind from being drawn to thoughts of chilly evenings and the annual realisation that I don’t have enough jumpers.

Yes, I’m already thinking about winter and wondering how cold it will get this year. Last year I managed to avoid switching my heating on until well into November, and I wonder if I can push it to December this year. I’m lucky though, my home is well-insulated and easy to warm up.

The building I live in is only a few years old and seems to have been built with energy efficiency in mind. Underfloor heating is standard in each of the well-insulated, double-glazed flats. I only recently realised that I have an Economy 7 electricity meter too, but I’m not sure how practical that is for me. I usually only have my heating on in the morning and evening. And it’s a small flat, so using my washing machine at night wouldn’t be ideal.

Is underfloor heating for you?

My rented flat is rather poky. If it wasn’t for the underfloor heating, I would have struggled to find a home for my modest amount of furniture. With no radiators to get in my way, I was able to squeeze in my bookshelves and drawers with the minimum of fuss.

My heating system is electric and seems fairly energy efficient. The most efficient underfloor heating systems benefit from heat pumps to draw warmth from the ground or the air. Unfortunately, a heat pump doesn’t appear to have been a practical option for my block of flats.

Are you tempted by the idea of underfloor heating for your home? If so, now is the best time to get it installed.

Water heating systems are complex to install, so you’ll need a professional engineer to fit them. Electric underfloor heating is less expensive to fit and there are some kits that a keen DIY enthusiast could tackle. You’ll still need a qualified electrician to connect your system to the mains, however. I was lucky to move into a home where the hard work had already been done.

Heart-warming radiators

I must confess, occasionally there are moments when I miss radiators. When I had the heating on in my previous flat, it was handy to be able to dry clothes on my nice, warm radiators. I also miss being able to stand next to a warm radiator after a walk in the cold. Lying face down on my hardwood floor just isn’t as cosy.

Which heating system warms the cockles of your heart? Do you already have underfloor heating? Do you think it’s better for your energy bills?

54 comments

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Argonaut...

Given a choice between underfloor-heating and radiator
emissions, it is the former every time as it provides better
and more effective heating all-round.

Long ago when I came here to study, I was put up in a hall
of residence for a winter term that had both forms of heating that
was very warm and comfortable. The bathrooms had both these
forms of heating too.

In London SW1 nr Harrods, it was much too valuable a piece
of real estate for student residential use… last heard of
it was converted to Crown Court use that presumably is still
continuing.

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dieseltaylor

My understanding of the electric kit underfloor heating is that it has a limited life span around a decade but mileage may vary with use. When we revamped a small bathroom we did have it fitted under vinyl as for a very small space it was very cheap and easy to fit. An electrician connected up the controls etc.

For light use fine. Installing it in a conservatory under tile I think could be expensive in usage, and expensive when it goes wrong to put right. Electric is an expensive form of heating normally so I would not rush to install it.

The main heating here is a gas fired air system. I replaced the 40 year old Lennox burner with a modern Lennox which is claimed 98% efficient. It is also a sealed system unlike its predecessor so the air for burning and the exhaust gas is all outside. Additionally you can add aircon and charged filter system. In our climate the aircon is unnecessary particularly as the air system will blow air around in the summer if required.

The house is a 1960′s with huge amounts of window so the solar gain in the morning and during the day is vast so a wet system would have trouble adjusting to the rapid rise. The flipside is even double glazing cannot stop quite a lot of heat loss during the heating season. : (

I did have an wet underfloor system installed in a new extension at a previous house which I put under tile over concrete as that is the most efficient transfer system. Roughly 40 square meters was sufficient to keep most of the house warm – effectively it was a giant storage heater but gas-fired.

I have considered air source and ground source heat pumps and I do think there is some benefits – huge benefits if you do not have mains gas or your own private woodland. I think it is a technology that needs to be more known as though it will not suit everyone it is an option that ought to be in the frame. Beware of cowboys as new technology can sometimes mean someone is using you as a training chance!

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jpjhughes

I too have a 1960′s house with huge amounts of window. But it has a wet radiator system. I’m guessing converting to an air system would be prohibitively expense – we have concrete floors downstairs. Any thoughts?

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dieseltaylor

Very unlikely that you could reasonably retro-fit a hot air system to a property. Having said that all calculations really should be based on how long do you intend to stay at the property and how much are you willing to spend.

There are a couple of things to consider. The forthcoming generation of CHP boilers where you can create your own electricity whilst burning gas that heats water/house. There are three systems that I know of all undergoing trials in houses. There may be more companies and they all have slightly differnt technologies and strengths. Some rate electricity generation higher than heating etc.

Heat-pumps are a technology i like and have been improving quite quickly in performance. As I am not currently buying I only keep half-an-eye on the market but you can get blown air, heated water, heat boosted water ………

An interesting technology much adopted in countries other than the most of the English speaking world. A big hit in Japan where the Government put some serious muscle into making it a very common system. Also used on the continent,

I also only have a hazy idea on the various solar offerings whether electrical generating or water heating. Here again apart from buying an immersion heater already fitted with additional pipe-work if I Invest I only take a passing interest,

There are more uncommon ways to heat property such as painting walls black to harvest the heat from the sun etc, but this only make sense if you intend to stay at a location for a long time – 10 years plus.

Anyway a lot of information is here:
http://www.energysavingtrust.org.uk/About-us/About-us

Whilst on technologies ignored by the

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dieseltaylor

Katie – As you have Economy 7 this might be a useful read. Its quite exhaustive and runs to nearly
6,000 words.

http://www.moneysavingexpert.com/utilities/economy-7

I am a little bemused though that if the flats are purpose built with electric underfloor heating then the assumption must be that the meter is for the underfloor heating. Perhaps the residents company can explain it,

Incidentally there is a fair bit of research on how the position of a flat within a block has a marked effect on heating costs. Ideally you want a middle, possibly top floor non-end flat. As you can appreciate if you are surrounded by other flats then you should be benefitting from their heating.

Thank you for that link, Dieseltaylor. I’ll certainly be adjusting my thermostat to only use heating during the night when the time comes to switch it on.

I definitely benefit from the position of my flat. Although the building is quite exposed to winds from the north, my flat is on the fourth floor with one further floor above and flats on either side. It makes it harder to cool the flat in the summer, but I can live with a bit of discomfort if I’m saving on my bills in the winter.

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Chris Gloucester

No doubt underfloor heating does provide more evenly heat distribution in a room and it will allow more flexible positioning of furniture.

But installation cost is much higher than radiators because of the extra floor insulation and kit needed and if anyone thinks it’s more economical on a day to day bill paying basis they’ve either found a way to defy the laws of physics or they’re deluding themselves.

Underfloor heating using a mains gas boiler wet system will result in your bills remaining much the same given you heat to the same temperature. Although some saving might be possible with zone control, but you could fit that with a radiator system, it’s a factor of the control system rather than the heating emitter type. Electric underfloor heating, like all electric heating costs much more.

Underfloor heating can be very nice, very comfortable, very desirable, but a cost reducing measure it won’t be.

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john

they are not deluding themselves, and no breach of the laws of physics is needed.

A radiator system set to keep your feeling warm when sat in front of the tele will have the ceiling temperature up around 30 Celsius or more. Underfloor heating inserts the heat where you want it.

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Phillee

I am just about to buy a water based system, is there any early feedback or reports on which manufacturers and control gear are best buys?

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Andrew

Hi, How did u get on, we are about to buy a wet under floor system love to know how u did it?

Andy & Lesley

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IanW

My last flat was a new build, with a wet underfloor heating system. No wall space taken up with radiators was good, but I really didnt like the big delays in heating up or cooling down. Also, underfloor heating in the bedrooms just wasnt practical. You want a bedroom to cool down overnight, but then heat up a bit in the morning when you get up. An underfloor system just doesnt react fast enough for this.

New house has radiators, which I much prefer.

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TC

I agree with IanW regarding the heating up time delay with wet underfloor heating. During Spring and Autumn, when the mornings are a little chilly and the days are still relatively warm, the room thermostat cuts-in early morning to trigger the underfloor heating. This then takes four or five hours for the heat to come through into the room, by which time it is not required: Result – gas used for no reason! One way around this would be to set the room thermostat to a lower temperature,

Upstairs in the bedrooms, we have a wet radiator system with room thermostat, which gives almost instantaneous heat-up and cool-down properties such that the problems IanW relates do not occur.

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Mark

We have just renovated a house and put in water underfoor heating in app 80sq meters under solid floor tiles (powered by oil boiler). Previously radiators. The most vital part to make this work is getting the correct thermostats put in which can keep the floor at the correct temperature at the correct time. As the floors have a huge mass – the key is to keep the temp in a curve. Cooling gently overnight but getting heat in the early hours gently to have it right during the day. For app £60 you can get room thermostats which check actual room temp, and when you want room at a desired temp – they will then fire up your boiler/ heat source at the correct time to achieve your desired temp at desired time. Initially we had standard thermostats and we either baked or were chilly , with these new ones, combined with a weather compensator controlling temp of water in underfloor we have saved app 30% fuel costs and achieved a superb living temperature. It is 80% in the controls and 20% in underfloor water system. Make sure your heating engineer is up to speed on the controls and not just putting in standard stats.

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lenw

When my bathroom/shower was refitted 4 years ago I had underfloor electric heating in addition to hot water radiator/towelrail. And extra wall insulation was added to external walls and thicker insulation in loft. Result floor tiles are warm to the feet with minimal extra electricity cost. Note though underfloor heating is only 150 watts per sq metre. That’s enough to warm the tiles but not to warm the room. The hot water radiator is small but enough to warm the room and avoid the need for dressing gowns etc. The whole lot is controlled by time switch and thermostats (essential). Snug. Don’t think I would even contemplate doing this for the rest of the house.

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Mark

Control gear – Danfoss TP7000 Si programable stats in every zone. These have algorithyms to work out when to fire up heating systems based on temp you want and current temp in room.

Kanmoor 374e Weather Compensator to control water temperatures in underfloor system

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old kitkat

I get sick of people who talk about ‘switching on my central heating’ in Nov or Dec. Why not use your thermostat an let your heating come on ONLY when it is cold and then it will switch off when your house is just as warm as you indicate. Out all day? put the stat down when you leave and up when you come home. People come into my house and say ‘Have you got your heating on? We havn,t started ours’. I say.’ It was on at 8.00 am for about thirty minutes as It was cold but the radiators are still warm.It won’t come on again till the temperature is very low.’ Mine is switched on all the year round but only ‘kicks in,’ in Autumn, at first only in the early hours on specially cold days. It never came on all through late spring and summer so why switch it off?

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Brian

No point being sick about it – take a tablet!
I left my UFH on all summer with just the thermostat controlling when it came on. That’s when I really found the problem with the slow response time of UFH – by the time it takes effect it’s either bedtime, or a the weather has changed and it’s not needed. So now it is manually set to off until the cold spell takes a hold, and I rely on a wood burner until then for short burst of heating.

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cranesbill

Like you I have the heating on when it is cold and if it happens to freeze in May or even August, then it comes on. The only difference is that as I am out during the day a lot more in summer, I tend to have it only on the morning evening setting but as soon as it gets colder or the days get less inviting, I have it on all day. I have started dropping the temperature a bit if I am out all day but not so much that the house is cold whenever I get home.

I cannot see the sense in holding off until November or whenever. If I could cope with extra jumpers until then, why not simply cope with extra jumpers all winter. If it is a matter of not being able to afford it then I would use the extra jumpers and thick socks all the way through winter.

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David Beakhust

I use gas with a condensing boiler (combi) and radiators.
If was having a new build and I had no gas available I would use underfloor and a heat pump, as the heat output can be three times the electric power used. This ‘coefficient of performance’ is higher, the smaller the temperature difference between the heat source (ground or air) and the heat sink (the underfloor pipes or radiators). This is determined by the laws of Thermodynamics, so let no salesman tell you otherwise (although installation costs would be a factor to offset against the higher “efficiency”). As underfloor runs at a low temperature and radiators at a relatively high temperature, using a heatpump with radiators, though possible, is inefficient. In short, underfloor and heatpumps seem to be made for each other.

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Chris Gloucester

Yep but no better than mains gas with rads, perhaps even not as good.
But against LPG or Oil then yes go for a heat pump with underfloor, if you can afford it.

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Convert, Sidford

I had a gas boiler and radiators. A bad radon problem necessitated drastic measures, so we decided to fit underfloor heating with a wet system at the same time. Research indicated that if we used a gas boiler we would gain approx. 25% saving in gas usage. I decided to use a ground source heat pump. The effect has been remarkable. Even when the house was still not properly insulated, we were running the heating at considerably less cost – and that is using electricity (to power the Heat Pump). The reason? The circulating water runs at a much lower temperature than it would in radiators (between 28 and a max of 50 degrees C and therefore efficiency is much greater. Will I recoup the cost in savings on fuel? Possibly. Is it more comfortable? YES. Is it easier to arrange the room, as already mentioned, this is a big plus. Maintenance costs? A lot less, and we don’t have to worry about gas explosions or carbon monoxide. Just a few thoughts

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Chris Gloucester

Think your savings came from the extra insulation associated with the underfloor heating installation and control system rather than from it simply being an underfloor system. A kilowatt hour of energy is a kilowatt hour of energy, the delivery system makes no difference. Savings come from insulation and/or the difference in price of the energy source, mains gas, electricity, oil, LPG or solid fuel.

Heat pumps work like a fridge in reverse and you can get out as much as 3 kilowatt hours of heat from a one kilowatt hour input of electricity, sounds great but a kilowatt hour of electricity costs about three times that of mains gas. Still better than oil or LPG of course but no real advantage over mains gas and the heat pump (and floor insulation) installation ain’t cheap.

So you may well have saved on your bills a bit but not simply because it’s underfloor heating. It will be the other associated factors like insulation and fuel type coming into play to give the saving.

But as said before underfloor heating is nice and I’m not knocking it, but in itself an energy saving measure? – no.

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Aitch

Underfloor every time, preferably wet, with a gas boiler. In a well-insulated house, electric’s fine, though, especially with economy 7 – heat the place up at night and it should stay warm or most of the day. As for somewhere cosy after a long walk, a log-burner is ideal…but perhaps not in a flat! Air-source heat pumps tend to be noisy, can be expensive to maintain, and burn a lot of electricity; they also give you least heat when you need heat most. Ground-source is better but expensive to install, especially if you have limited land and have to drill deep.

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Brian

Oh the smugness of someone on gas!
For GSHP you do need lots of land or expensive drilling of bore holes. But if you have the land it is probably a better bet than ASHP.
ASHPs are not all noisy – I have one (Hitachi) producing around 12KW and the noise is quite tolerable, barely noticeable except when it needs to be on full blast (which is, unfortunately, when it’s dark and cold outside – so it is at its least efficient.) It does not require much by way of maintenance – mostly keeping leaves clear of the cooling fins, and a service less often than a gas boiler.
My ASHP drives wet UFH – seer my other comments regarding the time delay in it being effective – but it’s OK once it is.

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P&KJ

Underfloor heating in bathrooms and kitchens is marvellous, underfloor heating in living rooms & bedrooms is NOT – I know I have lived in a house with underfloor heating. The heat gets trapped under sofas, cupboards, beds and wardrobes etc. and does not circulate efficiently. Keep underfloor heating for bathrooms, kitchens and utility rooms – all other areas keep to radiators or equivalent.

On the subject of economy 7/off peak electricity, I have also had experience of this. We had a washing machine & dryer with a timer that I set to run during off-peak times which saved money. I have also lived in a house that had electric storage heaters and ran them mainly during the off peak period again saving money.

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Bryan

I fitted wet underfloor heating to an extension in my house and was guided by the “experts” to use a screed and tile floor finish for maximum efficiency. The problem with the system, even using smart programable thermostats is that if anything changed, eg. you have 5 or 6 visitors the heated screed acts like a huge storage radiator and the extra Kw or so per visitor sends the room temperature soaring, so much so that we have had to throw open the patio doors in the middle of winter snow storms. I later converted the rest of my ground floor to underfloor heating using pre shaped insulation with alloy spreading plates and the thinnest oak flooring I could find. This system works very well and adjusts the room temperature quickly and efficiently to allow for use of the log burner and visitors are no longer a problem.
Since then I have refurbished my late fathers house and converted a barn on my small holding, I used ground source heating and underfloor, under oak everywhere apart from the utilities and wet rooms in both very successfully and also retrofitted ground source to my own home to replace the oil boiler.
The solar PV panels on each of the three buildings help to keep the running costs really low.

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john

who visits you – elephants?

People at rest give off about 100 watts each, not a kilowatt. Dancing may get them up to 200 watts.

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Bryan

OK. so I was using the same guestimate that comment number 4 was using hers: http://cosmoquest.org/forum/showthread.php?97274-How-much-heat-does-the-human-body-produce

But I can assure you that in a well insulated room, even one that is over 5 metres by 5 metres with 4 metre ceiling 3 or 4 extra people sends the temperature soaring during the course of an evening, even more so if we play on the Wii sports.

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dieseltaylor

Interesting experience. My extension was around 8 mtrs by 5 mtrs AFAIR with a central pitched glulam beam with a ceiling of structural insulated panels with multiple external glazing and three Velux windows. We never suffered a heat build-up but possibly that is because we had two openings of 6ft by 8ft into the main house which provided circulation to the rest of the house.

As I said we used it as a giant heat sink leaving it running on a relatively low water temperature all the time.and only in the coldest weather would we use the radiators to heat the house or particular rooms.

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Ed

Ahhh I inherited an underfloor heating system which has never worked properly.
I work for a national contractor and have had serious specialists looking at it because the supplier did not have any technical support that would visit the site. Ie help troubleshooting the issues.

Make sure you get a product that offers a professional tech support.

If u move into a house with it make sure it is tested properly with u witnessing every zone working properly and understand how to maintain it properly. Could be very costly otherwise or very cold as a consequence!

Costly? Oh yes it is to run. I’ve got a 4bed fairly big house with only the boiler running water for showers and the heating and my bills are over £150 a month. Would I do it/have it again. Never. And that’s coming from a builder……

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Would you replace your radiators with underfloor heating

If you are considering underfloor heating to an existing dwelling it will be disruptive as you will probably have to put a floor on top of you existing floor which could mean raising door frames and replacing skirtings. On a radiator system the water circulating could be as high as 80C whereas with underfloor heating the water is kept to a much lower temperature of 50C to prevent damage to the floor. This type of gentle heat is ideal for buildings needing heating constantly. Is is slow to response which is why it is not recommended for conservatories ( the room can become overheated when the sun comes out and the heat is stored in the floor slab with nowhere to go. In a dwelling with doors and windows open the time for the temperature to recover will be much longer than with a radiator system).
Electric under floor heating is gaining popularity in bathrooms and kitchens, but you may still require somewhere to dry towels. Electrici heating requires no boilers, pipes or radiators ( all requiring space and maintenance) but electricity costs four times more per kilowatt than gas.
You need to become acclimated to underfloor heating and will find your home more comfortable if you have a radiant electric or gas fire for use when the outside temperature suddenly falls. Electric underfloor heating is cheaper to purchase and simpler to install, remember that you will need to heat water for kitchen and bathroom use which if done by electricity may require a storage vessel, and consider how you will dry or air towels and clothes.

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Aileen Mckenzie

I read the above with interest and some dismay as there seems to be a significant divergence in opinion, not to mention a variety of considerations to be taken on board when considering underfloor heating. We have radiators in the kitchen and sitting room and are thinking about building an extension that will extend the size of these two rooms. As this extension will have folding doors and possibly a glass ceiling we are wondering whether underfloor heating might provide the level of extra heating that we require. If not, then presumably we will have to continue to use radiators, which, I have to say, are not that efficient in the sitting room in particular. We would be loathe to change completely to under floor heating as we have new oak flooring in most ground floor rooms and have recently had the kitchen retailed. I would be appreciative of feedback on our predicament.

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MW

Response to post of 7th Oct re extension with folding doors/ glass celing .
We recently extended and also put in a 5 meter by 4m glazed extension – 2 walls glass with 5m opening glass bifold and 50% roof fully glazed. Extended underfloor into that room from main house under stone tile. Underfloor works brilliantly and as per an earlier post – this is in main due to fact each zone has its own thermostat. So what is effectively a conservatory has its own stat placed out of the sun, whilst the adjoining kitchen has it’s own thermostat. We set conservatory slightly lower temp. We never overheat or chill – just let the system run itself.
Note – initially as with any underfloor system you live with it and gently tweak the temperature on stats until you get the temp that works for you – then leave it alone. It is a totally different heat to a radiator system and generally you are more comfortable at a lower temp than a radiator system which gives a lot of heat higher in the room – a real temp gradient vs down where you are sitting. Underfloor keeps your legs warm for instance when sitting at a table – with radiators open might feel cold and have to run the heating up. We did make sure that all furniture in conservatory is elevated – ie with good air space beneath to allow the underfloor heating to work fully.

The best way to run underfloor is keeping rooms at base temp of say 16 degrees and not using it like a radiator system – switching it on an hr before needed as it simply will not work. If this is done then it is likely that the floor (slab) will heat up and with the “lag” in transference – you get a lot of heat later than you need it. The floor does not need to be many degrees above the desired heat in the room as the area compared to a radiator is huge.

Extremely important and as if not more important than underfloor heating will be to select glazing that has treatements to refelect heat in summer whilst retaining it in winter and as geed an insulation value as you can afford, Expensive but very good are SUNFOLD based in Norfolk. You can also add roof vents which will open automatically on those too rare days of extreme summer heat :-)

Good luck

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ED

Re: Aileen Mckenzie and MW’s posts.
We too are planing an extension into which we wanted to incorporate a lot of glazing for light. The design of the new kitchen uses part of the existing 1920′s house plus a small new build and does not leave wall space for radiators. We had not realised initially that fitting underfloor heating would involve digging out the slab of the existing floor nor had we fully understood the potential insulation problems that the glazing could cause. A lot of internet trawling and talking to builders, installers and suppliers later and I must confess that we are getting cold feet (pardon the pun).
So I was very interested to read your posts.
MW, is your glazed extension separated from the house by a closable door? and have you experienced a harsh winter with it yet?
Ours would ideally be a continuation out from the existing room (5mx2m extension) with lots of glass in the sides and roof plus bifold doors at the front. Underfloor heating would heat the area. We are worried that it may look great but be uninhabitable for parts of the year.

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MW

Hi Aileen,
I understand your predicament having “been there”. No – we do not have any door between glazed area and kitchen – it is a fabulous opening – 11ft width letting in all the light we wanted through into kitchen. Added to this we have a further wide opening at side to dining room – more bifold doors and retrofitted underfloor. main lounge remains radiators and actually most ineffective at heating vs underfloor. Wish we had continued through!

We have had one winter living with this – and our 1 year old played every day on the stone floor throughout – when snow on glass roof and icicles hanging down gutters and minus 10. We stayed warm, underfloor had no problem at all. I do think had we used radiators floor we would have been cold, space up at glass ceiling hot and room too cool. I never had a doubt about using u/floor and it proved the right choice for glazed area. (aside from fact little space for rads) As you point out though also key is the glazing insulation.

Happy to share specs. more info if helps as we also spent months researching both glazing/ door systems and very importantly underfloor controls.

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Brian

The one big problem with warm water UFH is the slow response time. With radiators, if it turns chilly in the evening you can turn on the heating and notice the effect within 30 minutes; make that up to 6 hours with UFH. So it’s not worth turning UF heating on until there is likely to be a prolonged cold spell – i.e. winter – where the need for it is predictable. So you will need a secondary, quick heat source (such as a wood burner). I suspect that with electric UFH in a flat, this response time is less of a problem.

A related problem with UFH and a well insulated house – the insulation may well mean the heating does not come on very often – which is good news; but – you then won’t get the UFH benefit of warm floors and a more even heat distribution!

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Bryan

You can solve this problem by using Heatmiser smart thermostats, I use the slimline series. You just set the temperature you want at the time you want it and after a day or so of learning it will turn on early enough to achieve the set temperature at the set time.
It then continually adjusts as the weather and conditions change, it can occasionally be caught out by a very sudden change in the weather but that is quite rare.

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wavechange

I wonder if underfloor heating would be useful in older houses that are prone to dampness just above floor level. I will not call it rising damp because some people in the trade don’t seem to like the term.

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Beth

Our hall was once a Victorian school; it has large windows and a vaulted (insulated) ceiling so it tends to get cold in winter. Our present heating is ancient and we are planning to put in underfloor heating as we have a Kindergarten using the hall during the day and yoga and pilates classes in the evening so the heat is best at floor level. We have a small field so could use ground source although we are also considering air source, especially as we have no access to mains gas, plus there is a government incentive coming in next year.
Has anyone experience of underfloor heating in a community hall?

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Would you replace your radiators with underfloor heating

This is a perfect application for underfloor heating – no pipes or radiators taking up floor space or hot surfaces for toddlers to touch. Low grade heat (50C) is an ideal partner for a heat pump and underfloor heating application. Mind the field and hall will have to be closed during the installation. You can install underfloor heating on top of the existing floor using insulation and a metal deck. You would need to carefully consider the floor covering to reduce noise from the metal deck.

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dieseltaylor

Well I disagree with this mornings perfection idea! One thing you normally get with Victorian property is excellent suspended floors and the idea of putting something on top which is less giving needs some thinking about.

During the night I was pondering the problem and my thoughts leapt to a wood-pellet boiler. This may be able to use the existing pipework and minimise expense.

On the expense front we are given no size or budget but it occurred to me that if the land area is big enough the sale or a very long lease of a building plot could realise a very large chunk of cash that could be allocated to the hall as a sinking fund once the work was done.

You can go for a wet system or possibly more flexibly a space heater such as Fabbri. This site here allows you to spec the size of burner needed.
http://www.euroheat.co.uk/contlit1.php

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dieseltaylor

Blast it. A return key hit and it was posted!! Furshuglinner website.

I have read about wood-pellet burners things but have no practical knowledge so a fair bit of research needed. One other thing is that if you wish to go the geothermal route then you can drill and install effectively vertical pipes into the ground …. useful if you sell off the land : )
http://www.leam.illinois.edu/up466/natural-processes/lab-11-spring-2013/geothermal-heat-pump/l11-p03-geothermal-heat-pumps-vertical-systems-vs.html

Another couple of ideas are to install a heat exchanger so that your necessary ventilation requirement allows the incoming air to be heated by the stale air being extracted, and uncommon in the UK a reverse fan which is designed to throw the hot air in the upper part of the hall down to ground level. Probably not ideal for the badminton but otherwise ….
http://www.bigassfans.com/

Beth , perhaps you could give dimensions and budget as without those it is hard to be realistic. Also a big concern for me might be I can get a certain ambient temperature but need boosting for small, elderly, child groups and would need another system. Basically I am saying the usage of the hall and times might show that an air heat system is more flexible than a wet system.

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Fiona

A word of warning: when friends of mine moved into one of the Nash Terraces in Regents Park the underfloor heating cracked up the antique furniture! This is about 50 years ago so perhaps systems are better now!

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Dave

One thing that condensing boiler makers don’t tell you is that they only achieve the headline efficiencies of 90%+ when operating at flow temperatures of below 60degrees. Above that, and at typical wet radiator older design specification of 80degrees (modern systems tend to work on 65degrees), they might only achieve the typical 75% efficiencies of the old boiler you just chucked out.

This makes underfloor or over-large radiators significantly more efficient because they run at lower temperatures. One way out of this is to fit a weather compensator, which automatically modulates the boiler flow temperatures down, and into the high efficiency area, on the many milder winter days.

Only problem is many installers haven’t got the time or the knowledge to set them up properly.

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jpjhughes

I’ve largely discounted wet and electric underfloor heating for my project. I’m intending on replacing all radiators and pipework and replacing decades old boiler (55% efficient max) for a 90%+ condensing one. So what you say has me concerned I won’t get the best efficiency I could possible achieve. I heard about Low Surface Temperature (LST) radiators as an alternative and something that’s compatible with heat pumps. Does anyone have views and pointers for those? Thanks.

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MW

I believe you will need to have very large LST rads to get sufficient heat. Check carefully – you lose a lot of wall space which may be ok in your design. Having put underfloor in with new condensing boiler, decent controls and a weather compensator unit I would not want to move anywhere without u/f heating again.

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Would you replace your radiators with underfloor heating

Low surface temperature radiators are used in hospitals and buildings where the occupants are under 5 years old or over 60. They are basically a natural convector or a radiator in a cabinet which is warm to the touch even if the water circulating is hot (80C)

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jpjhughes

Sure that’s the traditional place for them. There was a paragraph or two in a renovation magazine a few months ago about LSTs specifically designed for use with heat pumps – from http://www.jaga.co.uk/

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Dave

You can still make significant saving with an older radiator system designed for 80C operation. Remember, the 80C is only required on the coldest days – I reckon 10-20% of heating days. On milder days, a properly set up weather compensator will turn down the boiler flow temperature, significantly increasing its efficiency.

Obviously, replacing existing radiators on such a system with larger ones, or double panel instead of single, etc, would also allow the boiler to operate at even lower temperatures.

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Eileen Littlewood

I worked in an office with underfloor heating downstairs and radiators upstairs (the two floors were open-plan so all heating should have circulated). Unfortunately working downstairs we were cold whenever the external door was opened and those of us seated at our desks had considerable feet/leg ache from the underfloor heating.

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Bonnyby

I had a conservatory made and fitted. It is small, 9 ft by 7 ft. I also had underfloor heating fitted in it.
My electric bill became dearer – now I have a fan heater and a plug attached that switches off after 1/2 an hour. Perfect!

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Niki

As we are intending to buy a newbuild house with airsource underfloor heating, I hoped to find some advice on the internet, but can’t find any. I fear that we should give up the idea as I have had a DVT and there is a history of pulmonary embolism in my family. I am 73 years old and would appreciate a reasoned opinion. I understand the floors would be heated to between 25 and 29 degrees centigrade.

Hi Niki, thanks for your comment. We have some information on underfloor heating, including pros and cons. Please follow this link to find it:
http://www.which.co.uk/energy/creating-an-energy-saving-home/guides/underfloor-heating-systems/

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dieseltaylor

I am surprised at the figure for the floor as it sounds quite warm to me. I wonder if that is actually the temperature of the water through the system?

Depending on the floor material the transmission of the water temperature to the floor temperature will have some losses. However I am relying on memory of my 7.5 by 4 metre underfloor system heating tiles through screed. Always wonderfully warm to the bare feet.

The heat you are looking for in a lounge would be 21C ish and because the heat is always coming up from floor level it is really very good.

I think you need to discuss it with the builder/installer as to the detail such as output , brand of the machine and then have a browse of the Web. Overall though I would leap at a underfloor heating for my ground floor. Upstairs would be a luxury but probably not justifiable … : (

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