Geothermal Heating

[mickey jim]

We are thinking of installing Geothermal Heating instead of a conventional Oil/Gas boiler.  We have the outside space for the 'Capteurs' and it all sounds straightforward/cost effective from the brochures (!), but does anyone have their own experiences of this method (or heard from other people), if so, it would be good to hear your comments.

Thanks.

[Btuckey]

Mickey jim,

 

We are currently having a house built in the Aude.  My wife originally did the research for available systems and came up with a solar system from Multibeton.  The nearest installer is in Foix and he said that he could not be bothered to come out as far as us (50km)!  Our builder must have sent them around twenty e-mails and they finally responded with a scrappy two page fax.  The builder then suggested that we try a company called SOFATH as she has dealt with their associate organisation ‘Vivrelec’.  They provided a very comprehensive thirty page quotation but only supply geothermal heating.  I was a tad cynical (!) and also had questions like could we leave the system on tick-over whilst we visited the UK at Christmas.  I telephoned their representative who said that as he was in our area that day he could see us in the afternoon.  As a rule of thumb, you need twice the heated area for the buried pipes.  As we have 250m2 of floor space, the SOFATH rep recommended 400m2 of piping in the garden.  The pipes are buried at a depth of 600mm and you can grow vegetables or shrubs on top.  No trees because of the deeper roots.  The rep speaks perfect English and I suggested that we repair to the local café to discuss the technicalities.  Thermodynamics was not my best subject at college and he spent over two hours patiently answering my questions and explaining how it all worked.  Again I was most impressed as we had not then signed a contract so this was all pre-sales for SOFATH.  They have earth temperature charts for the area and the rep explained how the system would provide almost all of our heating and hot water requirements.  However, we did expect to have to heat the water by electricity during the summer months whilst the heating was switched off.  In fact, this is not so.  We have chosen a reversible heat pump which cools the house during the summer.  The heat scavenged can in turn heat a 300litre water tank from ambient to 80C in just over an hour!  I ended up being very impressed....  (I later spoke to an engineer in the UK who stated that geothermal was much better than solar but was not used in the UK because of the land requirements for the buried pipes.)    

 

Simply repeating received quotations is a dangerous thing, as each installation is so different.  Ours was for circa 30,000Euros.  This sounds a lot, but we are heating 250m2 of floor area with a volume of 600m3.  The system is designed to provide an ambient temperature of 20C in the house, whilst the outside temperature is -7C, without the need for additional (i.e. electric) heating.  The system is also reversible in that the rooms are cooled in summer thereby heating the domestic hot water supply.  We looked very closely at the Return On Investment and the cost profile.  I am happy to pay more whilst I am earning in exchange for cheap running costs when I am retired.

 

Brian 11500  

 

 

[Micksyl]

Brian

I was desperatly hoping someone would reply to this question as I am planning to install in our property in the Gers. Would appreciate some further info if you have time.

1. Did this include under floor pipework ?

2. How have you heated upstairs rooms ?

Many Thanks

Mike

[Micksyl]

Brian

I was desperatly hoping someone would reply to this question as I am planning to install in our property in the Gers. Would appreciate some further info if you have time.

1. Did this include under floor pipework ?

2. How have you heated upstairs rooms ?

Many Thanks

Mike

[mickey jim]

Brian

This is really useful info, thanks for being so descriptive.  I also am interested to know whether the price you paid included everything (inside and out) or just the Geothermal external part.

 

[Btuckey]

Mike & Mickey jim,

 

Glad to be of help!

 

Yes, the price was for a 'turnkey system' so includes everything inside and out with the exception of the earthworks.  As this is a new build, our contractor has lumped the stripping back of the earth and replacing it into the main build.  This wasn’t expensive but I don’t have the exact figure to hand.  Once the earth has been stripped back the Geo company, SOFATH, lay the pipes and connect them to the heat pump in the utility room.  This activity is covered in the price.  We have a floor area of 250m2 (the maximum allowable under the SHON) and all living areas (220.6m2) are heated.  Inside, the quoted price includes the reversible heat pump, the ‘chauffe-eau bienergie’ 300 Litre dual heated water tank and all under floor piping.  Fitting and commissioning is also included in the price. 

 

To answer your second point Mike, the upstairs is heated just like the ground floor.  As with most new houses, the upstairs floor is laid as a huge concrete slab.  The pipes are then laid out as per the ground floor.

 

I hope this covers your questions, but please don’t hesitate to ask if you have any others.

 

All the best,

 

Brian 11500     

 

[Micksyl]

Brian

Geothermal it is then. Thanks for your responses.

IMike

 

[mickey jim]

Brian

Thanks for answering all our queries.  It's reassuring to get this sort of feedback.  Can I ask a couple of other brief questions:

I've read that there's a possibility for getting a grant for installing Geothermal Heating - did your installers mention anything about this?  If not, it still sounds cheaper than going the conventional route.  I personally really like underfloor heating however, we are moving into an old house, so unfortunately I don't think we'll be able to have underfloor heating upstairs, so will have to go for radiators.  But will definitely have underfloor heating downstairs.

Did you need planning permission/advise anyone that you were installing this type of heating ie digging up half the garden?

We look forward to going the Geothermal route too!!

Thanks once again

Mickey jim

[Btuckey]

Hi mj,

 

>I've read that there's a possibility for getting a grant for installing Geothermal Heating - did your installers mention anything about this?

 

Yes, our installers informed us that you can get quite a large grant for installing Geothermal.  However, it is paid in the form of a tax rebate so if you don't pay French income tax no grant....

 

>I don't think we'll be able to have underfloor heating upstairs, so will have to go for radiators.

 

I seem to remember reading somewhere about putting down a reflective lining and a 'thin' screed for heating upstairs in older houses.  Worth asking the Geo rep about it.

 

>Did you need planning permission/advise anyone that you were installing this type of heating ie digging up half the garden?

 

No, you don't even need a déclaration if the work is below normal ground level.  In our area this bizarrely also applies to swimming pools my near neighbour tells me!  However, Mairies being Mairies it is worth checking for your area.

 

Brian 11500

 

[Nick Trollope]

[quote]We are thinking of installing Geothermal Heating instead of a conventional Oil/Gas boiler. We have the outside space for the 'Capteurs' and it all sounds straightforward/cost effective from the broch...[/quote]

Last night we visited a French friend new house. They have installed geothermal heating for hot water only. The system comprises a ballon & pump and 70M of pipe buried at 1M (in a straight run, I gather).

Has electric backup, but they claim that it keeps 300L of water at a constant 65 degrees.

Power consumption of the heat exchanger is plated at 390W.

Cost (exc groundworks) was 2000E - a bargain in my book

 

[just john]

Hi Nick

This sounds much more cost effective and very do-able.

Do you have any more information, name of suppliers or installers etc.

Thanks and best

John & Sue