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Is underfloor heating really worth the effort


Fourbarewalls1
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Why is that no mater who I ask no one has installed underfloor heating or knows anyone that has it, why is this? I could really do with chatting with someone about there system before I go ahead a spend £10,000 on ours, this includes wet system, bolier, back boiler, water cylinder. I'm over in la Souterraine 2nd - 4th May if anyone fancies a glass of wine or coffee.

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[quote user="Gyn_Paul"]is there something I need to do with Opera, to make it quote without printing all the formatting codes?

paul[/quote]

Yes, change it to MS Internet Explorer  [+o(] - its the only browser that works fully with the forum software (I use Firefox [:D])

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Underfloor Heating is the only real option for Geothermal.

Why?

Unlike other forms of wet CH, which use radiators, UFH when correctly installed, loses little heat to the substrate, but radiates heat gently upwards via the floor.

Once the thermal mass of the floor has reached temperature, the floor heat creates a classic thermo-cycle, but at the bottom of the room.

Most radiators also create a thermo-cycle, but at the top of the room. (Try standing on steps with your head just beneath the ceiling in a room with a wood burner working at maximum and breathing deeply!).

People don't need heat just under the ceiling: they want it at waist height. UFH allows significantly less heat input to reach a cosy environment thus it's cheaper to run.

UFH also spreads the heat radiation uniformly across the whole floor: not just in localised "Hot Spots" around radiators.

Unfortunately, installing UFH in an established property as a Retro-Fit is not normally viable, due to the dislocation, mess and cost: it ought to be the first choice for all new builds and barn conversions (e.g.).

UFH is invariably used for environmentally friendly builds.

It is critical for the quality of ALL underfloor materials and workmanship to be of premier quality, since after the top floor screed is poured, it's too late for snagging!

Employing the latest synthetic materials, well designed and installed UFH should demonstrate a life expectancy of 50 years ++

I think that's all: but slept in unusually today and still slightly dozy!

 

 

 

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I have often wondered about this myself, the main drawback seems to be that you need to switch it on several days before you need the heat in order for the system to heat up the floors.

Conversely of course, if you've got the place all warmed up and the weather suddenly becomes hot how do you turn it off ?

I can't help but feel, that unless you live somewhere that is permanently cold it may well be a waste of money.

 

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Paul, I think it's probably a bug, but you could try switching from the design view to the HTML one (buttons at bottom left hand side of the text input window) to see if the formatting code is carried through to there, and then manually delete it?

Not perfect, but a workaround.

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UFH runs at far lower temps than conventional wet CH.

The aim is to keep the building at a comfort mean temperature level.

Most systems suggest that some additional source of heating is required (e.g. woodburner) for evenings in the main room/s.

Unfortunately, and as with so many engineering advances, all too often, realisations of concepts tend to be downgraded and thus defeat the primery original design philosophies.

UFH ought properly to use the latest control technologies, including flow measurement, zoning and most critical of all, external sensors feeding into the central control logic, as well as "Smart" controllers which "Map" usage habits and enjoy access to historic memory; for example, average ambient external weather according to seasons.

I recently posted some long overdue results from a chum who converted a bran in Wales a couple of years ago and heats this using geothermal bore holes.

He recently sent me an update from his latest electricity bill.

From interest, I'll post it again. This is the total cost for One Year!

As a further matter of interest, the total bill for the last (Winter) six months has dropped even further, thanks to more insulation: down to £ 790!

And this includes, of course, all the later price rises of circa 15%.

A wee bit better than oil-fired in France with fioul now at circa 91-92 cents per litre!

So, as I’ve said our single story cottage is approx 1900 squ ft. Insulation is basically stone walls with lime mortar 18” to 24” thick.

The a 2” air gap to permeable building paper attached to a timber frame with 50mm celatex under plasterboard. Half the building is normal ceiling height while the remainder is open plan 16 foot to eaves. Total Energy bill per annum is £1800. I’ve subdivided it up as follows.

 

Jacuzzi heating and filtration.   £400        35degC operates 24/7/12

Workshop power & light.          £150        Welding, compressed air, battery charging etc.

General Household.                £100         Computer, TV, domestic appliances etc.

Cooking.                                £150       

Heating & Hot water               £1000       Main room stats set at 18degC, Bedrooms 17degC. Hot water 49degC. Anti    

                                                            Bacterial High hot water set for 60degC every 30 days. Wood burner (12kw) used in open

plan area in the winter evenings. We have to be careful we don’t over do the wood burner

as it easily gets too hot!

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Really good technical explanations there Gluestick, without getting too techy. [:)]

We also have UFH, although electric, in our modern three bed bungalow. It's by far the most comfortable form of heating we've ever had.

We are all electric ie no gas, oil, woodburners etc., and our bills for the two complete years we have lived here were 764€ for 2006 and 825€ for 2007. I don't see this current year being any more expensive either. Having said that if you are installing in an existing property then the word is insulation, insulation and insulation.

The system works on zoned thermostats so there's no question of overheating if you use these wisely.

Yes, if heating from absolute cold in the dead of Winter, it can take up to 24 hours to reach full temperature but with today's modern delay timers and the possibility of telephone control from a distance this should never be a problem.

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Gluestick, thank you very interesting information. Off subject I know but regarding your comment on the hot water setting, I had assumed that the setting needed to be on 60 deg all the time to prevent bacteria in the tank. In fact a few weeks ago our plumber turned it down to about 50 and I noticed the difference and turned it back up.[8-)]

Regarding UFH, we have friends that don't like it at all. They say it takes too long to heat up and if you have a mild day it is very uncomfortable.

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It's a good example of the new programming technology, WJT.

Does it all autonomously, clears the bacteria and then back to low.

And saves cash.

Now he has finished all the building work, I am looking forward to my chum's further feedback through Summer etc.

We'll see what he says about Summer temps.

 

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I can only comment on the underfloor heating in my conservatory in the UK.In a word "fantastic".We don't have gas in France so no boiler but if I did then I would without hesitation put it in every room I could. Ours doesn't take days to heat up more like an hour or so and the cats absolutely love it.Rather an expensive cat basket though!
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It is true that UFH is relatively slow to react to changes in external temperature.  This is simply because there is  a massive block of concrete that needs to be heated up/colled down.  There are however things that can be done to alleviate this.  Modern systems with full controls and predictive programming go a long way, but also consider that with Geothermal and a heat pump it is possible to reverso that the system acts like a refrigerator and can actually extract heat from the building.  Like aircon.

 

Most of the negatives seem to be coming from people who do not have the system, but have heard that...................  Personally I would be very loath to change to another system, although next time I would probably consider the so called geothermal rather than oil.  Nevertheless we are consuming less than 1000l oil per year.

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Nice to hear a few positives about UFH,we have gone down the route with this for most of the ground floor areas (complete renovation project BTW).

We have spoken with the plombier[blink] and hope that we have the balance about right.The main two rooms (8.5x6.4m) & (8.5x5m) approx are heated floors,with the larger being a double height room.Both will have woodburners,the idea being to keep floors relatively cool and supplement that on colder days as necessary.The system is oil fired and hot water is aided by solar panels too.Had looked at geothermal,but were advised that it would not be up to the task in hand given size of house/construction etc.

Upstairs is normal rads and large heated towel rails in baths/showers.Thinking behind the system is to have an alternative supply always available.May work out a bit more expensive initially,but may prove worth it if any part should fail for any reason.

Cost is difficult to quantify at moment as we have not finished,may be able to provide more on that later. Also have made the old error of changing things as we have progressed(see Gluey's post!!) [blink]

Hoping against hope that all complete by July,but not holding breath!!

 

Johnnyboy

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I've always loved the thought of having underfloor heating & when we were house hunting saw a few properties which had it.  The rooms were lovely & warm & the thought of walking around with warm bare feet .....oh, lovely!!

My only concern is (& I'm not joking!) what would I hang clothes over, that need dried really quickly, without radiators!!  It's a trivial thought & I know there are probably very good solutions (including buying a tumble drier!) but it would put me off - sad but true!! [:(]

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Wet UFH doesn't prevent having a towel rail installed. You simply cut in a feed and return circuit before the manifold.

You can Mix 'N Match UFH with rads.

Best of all, a towel rail with an electric element too for Summer when the heating is possibly switched off.

 

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Having had UFH in the bathroom and kitchen in our last house in UK I wanted to have it throughout all of the house here in France.  It is not possible to have wet UFH because of door heights etc and thickness of screed, insulation and tiles, would it be possible to instal electric UFH and would it be economical?

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  • 3 weeks later...

Just to really confuse things consider electric underfloor heating - much lower initial costs, better response as the thermocouples are fitted under the floor, and low running costs. Typically we suggest around 16 degrees for comfort heat with an additional heat source such as the trusty wood burner - this comes out better in terms of overall efficiency.

It has to be said that it is also a whole lot easier to install and there is no maintenance.

If used in conjunction with some form of renewable energy (solar PV, wind turbine etc) to supplement the grid electric, then the electricity from your renewable source can be usefully employed elsewhere during the warmer months.

We have done the cost comparison exercise on numerous occasions and electruc UFH always comes out best. I hope that helps a little.

Marc

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Calculations are based on recent case studies - last 6 months or so - so have used the Oil prices the customers were actually paying. Electric prices based upon 10 centimes per kWk from EDF so France.

Selling electricity back to the grid is very viable with varied export rates based upon the type of technology used and in some cases the department. The only other factor other than buy back rates is the cost of EDF installing net metering equipment - around 800 - 1200 € as a one off.

Not sure I mentioned it in this forum but the buyback rates are expected to change next year (going down of course) as with other European countries so the race is on for many to install Solar PV prior to these anticipated changes to secure the 20 year contract from EDF.

Hope that answers the question

Marc

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I can't help thinking that with the poor efficiency and high capital costs/kw of pv panels, plus (at worst) needing to sell back 12,000 kwh just to cover the EDF connection charge, let alone the capital cost of the regulation kit, this is a technology with perhaps some way to go yet before it becomes a practrical proposition for most of us.

Still, it's an area I shall definately keep and eye on in the coming years

Ah.. just realised that the 12,000 kwh figure was based on selling back to EDF at the 10c rate. Like that would ever happen !

paul
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