Geothermal Heating V's Oil or Gas Heating

Kensington2 Image
10/03/2009 - 07:37

Does anyone have any idea of how much a geothermal heating system would cost to install in a house that is approx 380m2 v's a cost for a traditional heating and hot water system (oil or gas). I am just trying to work out if being 'green' is financially viable for us. Also costs on running would be really good....



Without specific information as to insulation levels etc., then it would be impossible for me to give you any real guide to what size heat pump that you would need or the cost.  Have you the thermal analysis for the house with regard to the heat loss against the heating requirement? Please do not get a plumber to estimate this, as unless they have the right software and the experience, then they will just guess. Use a thermal engineer to give you a accurate figure.I am about to install a geothermal system in a 220 sq mtr house ( completely rebuilt ) which has been running on GPL for about 4 years at an average cost of E5000.00 P.A. Calculations expect this to drop to approx 1500-2000 euros per year.( independent 3 phase pump supply + single phase for the house to keep to the lowest possible electricity costs ) Internal temperature is set at 20C with 24hr heating. If you have more information, then I may be able to give better answers, either on here or by PM.

Badger, would you mind stating how much you are spending on the Geothermal setup and approximately what the life expectancy of the setup would be? It would give us an idea how to amoritize the cost over the life of the equipment. Also, can you confirm the annual cost to run the equipment is based entirely on the cost of the electricity to run the pumps? Many thanks! 

Badger, would you mind stating how much you are spending on the Geothermal setup and approximately what the life expectancy of the setup would be? It would give us an idea how to amoritize the cost over the life of the equipment. Also, can you confirm the annual cost to run the equipment is based entirely on the cost of the electricity to run the pumps? Many thanks! 

AngieLThe setup costs are relative to the house size and the thermal needs of the house. Another consideration is as to whether you are going to be running underfloor heating or radiators. The domestic hot water running costs are minimal over the year, as the pump is only running about 1 hour per day, so for the installation here about 40 cents. Life expectancy: Pump circa 15 years, (compressor 10 year g'tee ) ground loops 100 years.For a 100-300 sq mtr house, expect to pay 1000-2000 Euros per year for 24 hour heating and domestic hot water. If you want to give me more specific information, regarding heating type, house size then hopefully I can answer better.Hope this helps 

The house is going to be a new build. Approx 380m2 and built to all of the current 'building regulations' in terms of insulation (ie walls and roof insulated, windows and doors with double glazing). I am sorry I do not know the technical side of anything else in relation  to the insulation. We are having under floor heating.We were just after a Rough guide to the installation costs so we can see if this is a viable option.Hope you can help.

If the insulation levels are high and the thermal analysis is good, then you could expect a pump size of approximately 17Kw output, as a maximum. Expect to pay circa Euro 20K, which would include the domestic hot water tank of 300 ltrs, plus excavation costs for the ground loops and plumber connection to the heating system.We have a installation close to us in a 300 sq mtr house with minimal insulation running a 17kw pump, so a better insulated house of your size should be within that criteria.

Thank You for the link to that web site - it was very informative. Do I take it that you are a project engineer for this technology?? If so what information would you need from me in order to provide me with a quote. I understand you are in Amandola?? I am in Tuscany - Pienza and the project is only at planning stage at the moment. Do you work that far away?

Kensington,  I wonder why you are starting off with a comparison with gas or oil. The cheapest energy sources in Italy are wood and solar and for €10,000 you can buy a good quality stufa with back boiler, solar panels, gas boiler (for boosting and back up) and a 475 litre DPS heat bank to manage all the energy and integrate all the inputs and outputs properly... running costs will be only a little less than a heat pump, but the general performance of the system is a bit more punchy and capable of running radiators and underfloor together and delivering astonishing rates of really hot water... all with no risk from legionella. You do have to lug the wood of course.Having levelled the playing field a bit I should go on in favour of heat pumps. I believe that relations between the West and Russia are going downhill and some believe that less favoured countries will suffer gas cuts - that's us probably - maybe within 5 years. It may be then that full on GPL gas systems will be looking like a big mistake in the future. You might notice that most renewable energy sources are delivered to you as electricity so it follows that the future lies with heat pumps for many people. We make sure all our systems are heat pump ready (or indeed work well with just a heat pump). If you are speccing up your house now I would urge you to go for underfloor heating as this is preferable in view of the low grade heat that heat pumps deliver when running efficiently.I'm just the other side of lake Trasimeno from you so pop over for a chat if you would like to..... the kit is all running here. We install almost ZERO GAS systems now but the PV solar panels are going on trial this week so I expect to be going ZERO COST on all energy quite soon but I won't claim that until proven.

Sagraiasolar. The heat pumps we use have a anti-bacterial purging system, which boosts the DHW to ensure that legionella cannot exist. The system can be set to operate this either daily or any time span up to 30 days cyclicaly.Running costs: With the new electricity charging, we suggest a single phase supply for the house, plus a 3 phase supply for the pumps, which although it gives 2 bills, allows the pump to take advantage of the lower charge bands. Using these new calculations, then we expect running costs to be even lower than those quoted above. I have not made the calculation yet, but will be doing so shortly, so will post as soon as it is complete.I agree that heat pumps work extremely well with underfloor heating installations, but can also work just as efficiently with radiators. The HT Plus models are specific in that they can heat rads to 65C and work with a combination of both systems if required.We have already installed a heat pump in Northern Italy (2004) which has compact collectors recharged with solar panels and as you will see from the link below this is being monitored and was the subject of a paper written for the International Heat Pump Conference in Zurich last year.

In reply to by Badger

Badger,  Thank you for showing me the solar recharging document - excellent bit of research and a clever use of the panels in winter. For conventional slinkys I have recently been wondering how good passive air conditioning might be.... ie not using the heat pump reversed but just pumping the water round the coils to recharge them in the summer.I hear what you say on producing temperatures up to 65c (good for legionella killing and heating radiators) but what happens to the COP at these temperatures? I can see that winter recharging with solar panels will help with this a great deal by reducing the delta T the pump has to produce.

In reply to by Badger

Hi Badger, are you still around?I'm busy restoring an old farmhouse in Cannara area and is looking at what would be the most effective system to install.You can contact me directly on nicobanderm@yahoo,com.ThanksNico

Hi Nico.Yes, I am still around, although do no get onto here very often, as do not like the format, or the way you cannot pm anyone, but that's life!!I have your pm on the other forum I now use and have replied there, with a email address.Best regardsBadger

Passive cooling is a better method in terms of economy versus a reversible unit. A reversible unit with an underfloor heating system, requires dehumidifiers as you are basically refrigerating the floor, plus it cannot continue to heat the domestic hot water. A passive cooling pump uses the ground heat, which is usually lower at circa 1.5 mtrs in the summer to just cool the floors, or it can be used in conjunction with special fan units to circulate the cooler air. It will also switch to giving the Domestic Hot Water priority at all times automatically.To kill off the legionella, the recommended heat is over 56C. with a DHW set at 54C and a 6C hysterisis, then every time the pump operates it raises the temp to 59C. This cycle normaly is of 5-10 mins duration and recurs every time the DHW drops to 53C. Peak cycling is only required if the DHW is set to circa 50C or lower, or the house is left unattended for some time..Normal COP is circa 4.5 @ 0/35C at 0/50 circa 3.3. (figures are European Standard EN255)Hope this helps.

Thanks for that ..... modern heating technology is getting so much better practically by the day... all very fascinating. I love the idea of having floors cooled, even a bit, by recharging the ground round the slinky. and it's free.I had a good look at the HT plus on various web sites. It looks like a very good bit of kit and I bet those 2 stage compressors - like the Sanyo CO2 as well - will become the way to go from now on.Perhaps if you get a job round my way we could meet up and maybe I could help.... we have a digger for slinky laying and we do plumbing sensibly and rather less expensively than usual.

Thanks for that ..... modern heating technology is getting so much better practically by the day... all very fascinating. I love the idea of having floors cooled, even a bit, by recharging the ground round the slinky. and it's free.I had a good look at the HT plus on various web sites. It looks like a very good bit of kit and I bet those 2 stage compressors - like the Sanyo CO2 as well - will become the way to go from now on.Perhaps if you get a job round my way we could meet up and maybe I could help.... we have a digger for slinky laying and we do plumbing sensibly and rather less expensively than usual.

In reply to by sagraiasolar

Don't know what happened to the original message as it was sent at 2.43 pm. This site is now so slow its a wonder anyone gets to read or reply to anything and I am on ADSL.

As I posted earlier, these are the costs that can be saved using 2 electricity supplies with each metered. The figure is based on last years consumption for the whole house and not solely the heat pump. Supply here is currently 15Kw 3 phase. Waiting for Enel to come and sort out for the 2 supplies 9Kw single for house and 6Kw 3 phase for pump.Comparison is last year total cost based on the single KW pricing. This year on the 4 level pricing for a single supply either single or 3 phase. And finally using single and 3 phase supplies each with own metering.2008: 9990Kw ......... total cost inc IVA and standing charges E25402009: Estimated 9990Kw cost inc IVA E27882009: Estimated 9990Kw cost inc IVA E2280 (using 2 meters)Using the geothermal pump (11Kw output x 2.2Kw input), the normal operating times x Kw consumption over the year are circa 4000KW, with the rest going on house use. Figures are based on 40% of the overall costs above.Running costs for 2008 circa E10162009 Calculated single metering E11152009 Calculated Dual metering    E912.In the case of using a single meter, once you exceed the 4440 Kw band then the costs rise quite significantly (circa 30cents KW)Using the 2 meters, each can keep on the lower tarrifs to the limit above (House use will go into the higher band) In our case we should save around E500 P.A. 

This not only concerns Geothermal, but also solar etc if you upgrade from an existing system to "greener energy". Please note it is only for houses that are upgrading, not for new builds. The regulations may change in 2010, but at the moment they are still current. Deduction is over a 5 year period. "Here is a short summary of 55% tax deduction. It is quite a complicated and evolving matter. The maximum deduction limits refer to the single building (unità immobiliare) and will be subdivided if there are multiple owners of the property involved in the spending. For any further information it is better to read Enea website. Only existing buildings can benefit of 55% tax deduction, no benefit for new buildings/houses. Buildings have therefore to be registered by local "Catasto". This benefit is granted for all works improving thermal and energetic consumption of the house, the complete list of works is available on Enea website, Amount granted are: -euro 100.000 for lowering energetic need of the building (new heating or conditioning system) (that is 55% of  Euro 181.818,18); -euro 60.000 for house insulation, windows including shutters, roof, etc (that is 55% of  Euro 109.090,90); -euro 60.000 for solar panels (that is 55% of  Euro 109.090,90); -euro 30.000 for winter climatisation systems (that is 55% of Euro 54.545,45). When all works are finished, a qualified engineer has certify that all works are complying with requirements, and can fill in Form E of "Decreto del Ministro dell'Economia e delle Finanze del 19/02/2007" and sent it to Enea by internet. Other documents are to be kept for eventual inspection of Ministero delle Finanze: -copy of all payments made by bank transfer, indicating: invoice number, codice fiscale + supplier invoices and partita IVA "Pagamento fattura nr.XX del XX/XX/2009, beneficiario detrazione 55%  pagamento (supplier with IVA details)." -receipt of Form E sent to Enea by internet; -certification made by engineer that all works are made in the right way; all invoices related to the works;" its an interesting point of view. apparently beefing up your insulation and buying really good windows is a better way to invest your money than any other alternative energy sources....   Paola

As I have not read this book, is the author talking about energy cost savings through insulation in the UK or US?  Obviously insulation is a major factor in reducing heating costs with whatever system you use. In fact you could heat a 200+ sqm house, very highly insulated, with just 7Kw of heat output. The comparison of energy prices, oil, gas, electricity etc are much higher here than the UK or US. The calculation is that 80% of boiler usage for a house is for heating, the rest for Domestic Hot Water. Whichever way you go, then you need a heating system of some sort, so there still is an additional cost, albeit less.

 The author is talking about passive houses http:// He is referring to the Uk, he is a Scottish Archietct, from a company called Gaia. Apparently passive houses can do without a heating or cooling system, a few have been built in Germany. For the skepticals, you could build a passive house and still integrate a wood burning system, or pellets... Paola

Thanks for the link Latoca. Just having checked through a number of the properties featured, then I see that they are using Geothermal applications (Warmepumpen in German ) for the heating source. I cannot really find one, that has neither gas, pellet, solar, air to air, or anything less for heating/DHW, but then I did not go through the 200+ installations. Have you the link to the Gaia site, as I can only find a few sites promoting wind energy etc linked to the name. I admit that I have no confidence in Architects and their knowledge of heating systems since one here in Italy allowed a Polish "plumber" to lay a few lines of pipes on a floor and call it "underfloor heating". We refused to even consider the installation. 

Bunterboy. You only need a 3 phase supply if the pump output is over 11Kw, other than that you can opt for a single phase or 3phase supply on the smaller size pumps. Electricity costs are exactly the same per unit whether you have single or 3 phase. You only pay a supply charge of E1.203 per supplied Kw per month. We here pay E18.05 for 15Kw per month as the standing charge, unit cost is the same a you may pay if you have over the 3kw basic supply. A 9Kw output pump needs under 3Kw to operate. Technical data: Output @ 0/35C 9.1Kw Input 2Kw (underfloor heating). Output 0/50C 8.4Kw, Input 2.6Kw. Overall, it is quite inexpensive to run a heat pump, relative to GPL or oil. Quite happy to give some further clarifications on running costs if you wish.

Thank's  Badger, I was thinking of the pump input requirement. So if it was 4kw and running 8hours in 24 it would cost around E6.40 adding on circulation pumps etc the cost would be  around E7.50 a day which works out at around E53 a week.Once you add in your normal electricity costs it  sounds a bit too expensive for us. I'll sort out the damp proofing, draught exclusion and insulation first and see what money we have left. Could be we might be taking Edwina Curry's advice of wearing wooly hats ......   inside.

Hi Bunterboy. These are actual figures taken from the 11Kw output pump here: I have covered the dates from 02/11/09 to 04/01/10, as have just received the Enel account for that period. This is one of the heaviest usage times, so it gives a better indication of what Winter accounts would incur. GSHP: Output 11Kw .......... Input 2.2Kw Temperature settings house. Heating 19C underfloor heating. Domestic Hot water 48C. Running times from pump computer: 454 hrs, daily hours over above period average 7.09. Consumption at 2.2 Kwh = 998.8Kw = 15.61Kw per day. Circulating pumps x 2 @ 60W each ( 1 for ground loops, 1 for heating ). Total Kw used for the house for the above period = 2102. Cost relating to this excluding the standing charges = Euro 600.00 including the 10% IVA. As you can see, it costs us approx Euro 300 for 2 months heating and hot water 24/7, if I split the bill 50/50. The 4Kw input that you state would be for a gshp of 17Kw output, suitable for a normally insulated house of around 300Sq.mtrs floor area. Have attached the link below, which gives all the data.

There is no reason why not Bunterboy, but if you did go for a heat pump, then I would seriously consider the 2 supply option that I mentioned earlier in this thread. Best if you compare the rates Bi to mono as I don't think you would save very much.

Excellent Badger- I really need to improve my Italian - however it seems the latest business fashion from telecom firms and energy providers is to make the pricing structures so complicated that most people are bamboozled and therefore less likely to change provider. The ENEL pricing is like something out of Monty Python's "Meaning of Life"-mind you British Gas has a similarly confusing pricing arrangement..well here goes!

while your most informative discussion goes on may I presume to chip in a bit.  I've mentioned before that I'm testing PV solar panels with the aim of having a cost free heating system. So far on grey winter days the output of a 20 panel car port hovers just under 1kW but shoots up to 2.5kW if the sun comes out. In summer the max output should be 4.6kW.  I borrowed the money for the kit so there is no capital cost apart from the €!0,000 deposit the bank always seems to like on these things. Now for about €30,000 you can get more panels producing over 5kW and €5,000 worth of combined income/reductions a year. So if you were considering a modest heat pump you could run it on a low tarrif 2 phase supply and on balance it would cost you nothing to run... no brainer really. If say 11kW was not enough on a bitter winter night you could always light the stufa.

PVs are good idea, and with a fairly large array you could "top up" your thermal store with an immmersion heater-not bother with the heat pump and use a stufa and solar thermal panels as the main means of warming up the heat bank.Certainly lots to consider, I was even toying with the idea of a wee wind turbine dumping its "excess load" into the thermal store too.

 funny you should say that Bunterboy. Having spent an unacceptable €36 on gas last month (too much cooking?) I'm just wiring up the (PV boosted) mains up to the immersion heater on the heat bank now. Sometime after lunch there will be a timed boost of the tank with a thermostat limiter... shouldn't use too much power as the wet solar panels kick in just after 8 on most days and do some of the work. With a big solarthermal array of at least 5 square metres you should get to be pretty much ZERO GAS all year round especially if you bias them towards the shoulder months with a 45 degree angle. I graphed gas consumption for a year without solar panels and now this last year with them has shown gas consumption almost eliminated - down by something like 70% and across the whole year. I think the immersion heater will prove to be the knockout blow. That's all possible and easily done too but I have to say that I'm putting my energy savings towards a heat pump as the next step in the quest for perfect heating. I'll be too old to lug logs one day and I already envy Badger with his GSHP. AS for wind turbines.  Don't get me started.

Going back to an earlier post here on income tax incentives for renewable energy heating systems. It appears you only have until the end of Sept to submit claims for installations completed in 2009. The current incentives are scheduled to finish 31/12/2010, but I will try to get further information if there is anything new for 2011.