Under Floor Heating ?

[SueP]

We'd like to put underfloor heating in the barn we are converting into a house. The solid concrete floors are already down (they were there when we bought it), and we've already put in an oil fired boiler to heat the water for the system.

We'd like to know - Best products to buy? Where to buy, UK or France? Is it a DIY job or should it be professionally fitted, and if so any recommendations for installation companies in south of Vienne department (86), or Deux-Sevres (79), or north Charente (16).

Does anyone have any hints, tips or advice - please !  :)

SueP

[bigjimbishop]

Underfloor heating is getting popular in France with many companies offering eco friendly and economic solutions.

It is a shame you have fitted an oil system being the most expensive fuel at 4 times the cost of wood per kW/hour

But as you have a floor prepared there are plenty of companies who can fit altenative systems to oil and electric with some government grants available (upto 50%)

Here is one

There are loads but I'll have to get back to you with details.

If you google chauffage ecologique or geothermique etc. you'll be on the right track.

There is a really nice system which uses ground heat in your garden consuming the same power as an average fridge freezer.

You need to have 3 times the garden surface to floor surface. It cools in the summer and heats in the winter.

Also commercially available from many french companies.

There are also wood pellet fires heating systems which run at I think 2 Euro cents per kW/hour compared to wood logs at 2.9 and oil/electricity at 7.9

(I hope I got the decimal point in the right place as I am relying on memory from last week with a few bottles of Aligote in between but the relevant ratios are correct)

It's a really hot topic here in the Morvan as we have an endless supply of wood so the foresters make pellets with the waste branches and leaves.

Forget the oil unless it is biofuel, also available for heating but still not as cheap as alternatives.

Don't waste time and money on UK companies as the french are far advanced in this field.

Good Luck.

[andyh4]

A lot of what Jim has said makes good sense, but is not necessarily helpful in your position.

Do not dispair, although oil is by no means cheap it is still cheaper than electricty or gas.

 

Although your concrete floor is laid, you can still lay pipes over that and concrete/screed over the pipes.  Provided you have the head room for another 4-6inches of concrete on the floor.

 

I would get it done professionally.  The laying is not that difficult but the splitting up of the pipes into zones and ensuring you have enough pipes in particular areas demands some expertise.  You could get it from books of course, but that all takes time and as Jim said the French seem to be streets ahead of the UK, so the better books are likely to be in French.

 

Your boiler will need to be able to provide low temperature hot water.  Systems typically run with 20-40°C input temperature - much cooler than rads..

 

Personnaly I would find it difficult to go back after 11 years of living with underfloor heating

 

 

 

[Catalpa]

We've just had underfloor heating installed. As Andy says, you'll need to allow a further 4 - 6 inches for insulation, pipes and screed then tile on top. Or you can install wooden floors but the quality of wood is very very important to prevent shrinking / warping. Don't use carpet because carpet insulates against the heat! and also becomes a breeding ground for all manner of bugs... who love a warm bottom!

Very competent DIYer can self-install but make sure you have no joins in pipes under the floor - have one run per room or even area and use a complete length of pipe out from and back to the heating manifold. Reason being, likelihood of leaks under the floor is much reduced if there are no joins.

A special screed is used to cover underfloor heating so ideally you'll need to find a specialist company to do this. Personally, I don't think this part is DIY. You also need to use specific floor tile adhesive and grouting which is, of course, more expensive than the bog standard stuff.

If you are installing it yourself, you'll pay 19.6% instead of 5.5% TVA. You won't (assuming you are a French resident) get the tax breaks - you need installation by a certified company for that.

Remember to calculate accurately the amount / spacing of pipes you will need to produce the warmth you want. I think there are calculators on various websites.

We've had a registered company instal ours because with this, I'm risk averse. I want the 10 year guarantee and if there's a problem, I want someone else to bear the cost of correcting it. There's also the tax benefit which is substantial.

Hope these random thots help a bit. [:)]

[Michael]

SueP[Simply put]On top of your existing concrete floor you install dpc membrane, at least 30mm insulation then your underfloor heating, then at least 65mm of floor screed, finish floor of your taste.The pipe you use is Pe-xc,Pex or Pe there are others on the market..The underfloor system is designed to operate at 40/50degrees centergrade.The rest of the system ie hot watertank/rads normal working temp. Underfloor heating controls ie manifolds ,zone valves,stats,.sensor valves,etc are a matter of your engs choice,they basically all work the same.Installing under floor heating pipes is simple once you know your circuits,how many in each room and so on.Its the temp /control thats critical to the pipe,to hot and it shortens the life of the system.Thats why there is thermostatic control and Bypass at the pump /manifold.I would say yes to you to install the pipe if you have the design ,but no to the controls etc,unless hubbys a very practical man.Not a safety officer or what ever...Have fun, Michael.

[SueP]

Thanks, very encouraging! Please can you tell me where to find a Registered company in France for this type of thing? So far we've only used a plumber and roofer in France, and they were recommended to us.

[Michael]

 Sue P.In your area any competent plumber/heatinging eng should be able to fit your underfloor heating to the existing boiler setup,If you already have a recommended chappy he should be able ,or to recommend a fellow eng or firm.Underfloor heating is really a simple job for any trained plumber.Or go to the local Builders merchants/ Heating suppliers, the trade counter would prob put you on to somebody. Michael. 

[Catalpa]

Well, yes, any plumber should be able to do it... but personally I think you want someone who has done an installation. A number of installations. With these things, I don't want to be the first installation the plumber has done - his guinea pig, the one he makes his mistakes on.[:-))] Underfloor heating still isn't so popular every plumber is experienced in the procedure. This is especially so if he is going to do the floor plans for the pipes.

Our situation is more complicated than yours in that we have solar panels and a 750 litre balloon with a pump to circulate hot water to the bathrooms 3x a day so we wanted to be sure the whole system would talk to each component piece. This reduced the number of companies we could use and we ended up getting quotes from 2 companies. One was recommended to us by Dedietrick (sp?) the solar panel company and the other we had seen doing work elsewhere. Michael is right that the trade counter of large plumbers merchants (in this area we have Brossette) will put you on to someone - Brossette have worked with our company not only on supply of some of the equipment but also in obtaining the pipe floor plans from the supplier. It's surprising how often TOH called in for plumbing bits for us - and found a full-blown meeting on our project underway.[:D]

For the screed, there's an added component mixed in which... well, we can't accurately remember what it does! conducts the heat better probably - but we got the specialist screed company on recommendation from our heating company on the basis that they were unlikely to recommend someone whom they didn't trust to do a good job as a poor job would potentially end up in problems for them. I can't remember if I said earlier but this screed is very water-y when it goes down (to enable good flow and seal around the pipes I assume) and the residual powder has to be "polished" off before tiling can start. Approximately, from the final screed going down, it is 48 hours before it can be walked on, +3 weeks to dry ambient temperature, + 1 week with the heating on at minimum for further drying. Polishing can then happen and you're off and running with the tiling with the right adhesive and grout.

I can't remember if I said earlier how pleased we are with ours so far. It is a very different form of heating. You won't need the temperatures you tend to strive for with what I call "spot" heating - woodburners, radiators etc, because the whole room is warm.

[Unknown]

I have found this thread very interesting as this is something we would like to do in the future of our resto.

This is going to be a long way off, but I'm interested to have idea of how much this costs.  If anyone can pm me or are happy to post their costs I would be most greatful.

[Michael]

 Dotty .Why not down load information from one of the leading firms in uk/europe.In Uk they used to be called Wirsbo, now the trade name since Jan 06 is called Uponor at,www wirsbo.co.uk.For the self build etc become one of there registered users then you can download all the Technical info and send for there fact sheets on general installation guides.I have used there materials on and off for the last 20years in some of my projects.Michael .Oh and i have no shares in the firm...

[Unknown]

Thanks Michael, was just being lazy.