Geothermal- The way to go or not?

bauney

Hi, I'm doing a self build and planning is submitted but i'm not 100% sure what heating system to use. I've read lots on the web and on this forum but i don't know whats best.
I want underfloor heating(UHF) for obvious reasons. i.e. large open plan kitchen area, concrete floors upstairs, no rads on walls.......
From what i know, it appears oil/gas is very expensive for UFH. So i'm kinda swaying towards a heat pump (geothermal or aerothermal). I know installation costs are high here and electric costs are more severe but i feel its my best choice.

Has anyone any opinion on this as to what might be best? Is aero better than geo? What other alternative is there to heating UFH?

Regards

mark2003

Geo would be more effecient than aero,especially with the cold winters we are after getting. Im just after builing a house and put in geo heat pump. If your house is well insulate and airtight,electricity bills will not be high(my total electricity bill for Dec and Jan was 245euro in total). Get expert advise and try and have an A rated house.

tred

bauney wrote: »

Hi, I'm doing a self build and planning is submitted but i'm not 100% sure what heating system to use. I've read lots on the web and on this forum but i don't know whats best.
I want underfloor heating(UHF) for obvious reasons. i.e. large open plan kitchen area, concrete floors upstairs, no rads on walls.......
From what i know, it appears oil/gas is very expensive for UFH. So i'm kinda swaying towards a heat pump (geothermal or aerothermal). I know installation costs are high here and electric costs are more severe but i feel its my best choice.

Has anyone any opinion on this as to what might be best? Is aero better than geo? What other alternative is there to heating UFH?

Regards

Cost it. Compare it against the alternative, and add interest over 25 years to both figures if its coming out of a mortgage, then see where you stand. Also, what is the lifespan of these heat pumps. My buddy in sweden has aerothermal, heating radiators. But, the biggest advantage they have, is they have Neuclear power, and electricity is not pegged to oil prices.

L driver

Hello,
Yes cost it and see. The first thing is to make sure you are using little of anything to heat the house, get everything else right first and some would argue that no major CH system is needed at all. Take your life style into account....kids/other half. The problem with oil/lpg is meeting the reneweables then you have to add in solar and so more pumps/controls/tanks. Then capital costs seem to be getting closer as well, oil+solar compared to gshp. Fuels, except our sun, are always going to rise in cost. Until we get our electricity from sellafield or build our own nookie plant our power is linked to the same fossil fuels. Sorry just read my post and it is like thinking aloud, not very structured, I'll slap it up anyway. But fuels and power in the next 20 yr will be crazy imho and as I said at the start build to have to use very little.

galwaytt

bauney wrote: »

From what i know, it appears oil/gas is very expensive for UFH. So i'm kinda swaying towards a heat pump (geothermal or aerothermal). I know installation costs are high here and electric costs are more severe but i feel its my best choice.

Has anyone any opinion on this as to what might be best? Is aero better than geo? What other alternative is there to heating UFH?

Regards

You 'feel' it's your best choice ? Research, research. And then research. Don't rely on 'feeling's for stuff like this. Get objective.

Design your house to need little (or no) heat, for a start, and the heating system choice will become less relevant - in the main, I like the ASHP idea, but electricity prices here are hideous.

My house being built at the moment and im deciding on heating system too. My house = 2500 sq ft

Heres where im at on cost research.

1. Oil tank and boiler, Stove(solid fuel - turf) with boiler, !6 rads,towel rads, Solar panels, buffer tank and all the necessary pipe work is 11500 euro approx. Plus labour to install(Someone might give me a rough figure here)

2. Air to water heating system with ufh and labour to install = 15500

3. Geothermal with horizontal collector with uhf(fully installed) 17000 euro. Plus one day machine work for installing horizontal collecter

4. Geothermal with bore holes with uhf(fully installed) 16500. The big cost here is the bore holes. I need 2 80 meter bore holes which would cost ?? ANyone?

Anyway ive visted a few houses now and seen some surveys so i can make these points

House 1- Air to water
Running the air to water system will cost no more then 3.50 a day in the winter time at the moment its running at about 2.50. Pump rarely comes on in summer

Houses with goethermal(2500 sq ft)
Electricity bills were on average 1400 - 1600 a year. Around 800 - 1000 a year for heat pump

Tomo87

bauney wrote: »

Hi, I'm doing a self build and planning is submitted but i'm not 100% sure what heating system to use. I've read lots on the web and on this forum but i don't know whats best.
I want underfloor heating(UHF) for obvious reasons. i.e. large open plan kitchen area, concrete floors upstairs, no rads on walls.......
From what i know, it appears oil/gas is very expensive for UFH. So i'm kinda swaying towards a heat pump (geothermal or aerothermal). I know installation costs are high here and electric costs are more severe but i feel its my best choice.

Has anyone any opinion on this as to what might be best? Is aero better than geo? What other alternative is there to heating UFH?

Regards

Both are great technologies but have seen good and very bad products for each type. With the heat requirement on new builds getting lower due to better insulation windows etc, the payback looks more promising for air to water imo.
Suresanders costings seem alright from what i've heard, altho I would have said there would have been a much bigger differnce in groundsource and air source options. As for drilling the boreholes I would hazard an estimate at 3500-4000 euro. What size is your house bauney?

fclauson

go read http://www.boards.ie/vbulletin/showthread.php?t=2055874134&page=12 lots of good info

specifically the link I put to the energy trust document

I cannot make either geothermal or air to water stack up in terms of ROI

Spend the extra you would have done on these systems on zero cold bridging, and insulation - and then just use precision gas or oil heating to provide heat just when you need it

Francis

BryanF

fclauson wrote: »

go read http://www.boards.ie/vbulletin/showthread.php?t=2055874134&page=12 lots of good info

specifically the link I put to the energy trust document

I cannot make either geothermal or air to water stack up in terms of ROI

Spend the extra you would have done on these systems on zero cold bridging, and insulation - and then just use precision gas or oil heating to provide heat just when you need it

Francis

I totally agree with you on ROI of geo and this air to water is a cod, and getting the best Insulation and building envelope you can. people wont spend an extra few grand this this right, but will spend 15g on pretend renewable's (i'm referring to the electric consumption)

but then you go and ruin it all by saying use gas or oil?
for people doing self builds they are generally in the countryside, so they can sources there own timber/biomass supply, so imo i would look at a renewable source for your heating, if you cannot get a suitable supply of pellets,willow or other biomass then consider a log burner, its just like a boiler that you put a few logs into in the morning a forget about for the day, once a year you need a load of timber and a shed or covered area to store it, very efficient and very cheap to run, and the most environmental way to go, that is once you have reduced your buildings heat loss as much as possible

putting in oil or gas may appear cheap on paper but you cannot control the future costs, and its all imported

L driver

Hi Bryan,
How much is a log burner, buffer, controls, fan assisted flues etc? What are the emmissions like? Might be a good system with a bit of elbow grease for 1 or 2 days chopping a year!

BryanF

I dont have a preferred manufacturer, I know many people go for Scandinavian/Austrian models, you may need to do a bit of research, sorry i cant be of more help.
I believe there slightly cheap than a pellet stove, I have some clients who installed the log boiler/burner so I'll enquire ( may take a few days)

sydthebeat

there are generally 3 types of wood burners, pellet, gasification, and log. the efficiencies generally fall from high 70's -80 in pellets to 60's with a log burner (mainly due to the unguaranteed quality of fuel)

if you have a large and constant supply of wood, then consider log or gasification as a energy output source.

creedp

L driver wrote: »

Hi Bryan,
How much is a log burner, buffer, controls, fan assisted flues etc? What are the emmissions like? Might be a good system with a bit of elbow grease for 1 or 2 days chopping a year!

I agree with the above but also I don't understand the strong anti-HP position taken by some. BrianF is correct in respect to the use of local renewable fuels as a substitute for oil and gas. However, there is no certaintly with respect to supply and price for any fuels. If demand for wood increases in time due to high oil/gas prices this will undoubtedly have a know on effect on the supply and price of wood. With electricity, in theory, it can be produced by a whole range of fuels including renewables and therefore you could argue that it has a better guarantee of supply. I know its sacrilege but it could even be produced by nuclear whether it be home produced or imported from the UK. In addition, to all that, in theory again of course, you could install micro wind turbines and/or PV collectors to generate on-site electricity. This might not seem very probable today but who knows where technology will go over the next 5 - 10 years. Therefore, for me the instant dismisal of a particular source of heating is a bit premature. Just because you don't like it doesn't mean it can't make sense to others.

DagdaIreland

I'd say it's worth checking out the costs more thoroughly for the ASHPs.
I've done a good bit of research on different makes and brands and their efficiencies, and I know there are cheap and cheerful (but unreliable and inefficent) systems out there.. but that's true for any technology (and gave biomass a bad name which it probably doesn't deserve).
I would suggest getting a Daikin high-temp heat pump with radiators (and/or fan-assisted radiators) in many retrofit situations (I'm not a supplier or affiliated with them) but in a new-build situation, an Ochsner Milennium air-source heat pump with underfloor heating is a real Rolls-Royce of a system with excellent efficiency and very low running costs (but admittedly higher up-front costs). I think in this situation, you need to be thinking of the return on your investment over 20 years, and I'm convinced this is the way to go in preference to oil or woodchip/biomass.
These sort of heat pumps can be got through a number of contractors (Google is your friend) but if strong guarantees around the installers and quality control etc. are important you could try ESB Halo www.esb.ie/halo - I don't think Bord Gais are doing them yet.

BryanF

bauney wrote: »

Hi, I'm doing a self build and planning is submitted but i'm not 100% sure what heating system to use. I've read lots on the web and on this forum but i don't know whats best.
I want underfloor heating(UHF) for obvious reasons. i.e. large open plan kitchen area, concrete floors upstairs, no rads on walls.......
From what i know, it appears oil/gas is very expensive for UFH. So i'm kinda swaying towards a heat pump (geothermal or aerothermal). I know installation costs are high here and electric costs are more severe but i feel its my best choice.

Has anyone any opinion on this as to what might be best? Is aero better than geo? What other alternative is there to heating UFH?

Regards

just going back to your OP, what is your architect recommending, what have specified for external envelope U-values and have you considered your ventilation strategy, now's the time!

Have you considered super insulating and air-tightness followed by MVHR and then worry about heating system.

fclauson

BryanF wrote: »

....but then you go and ruin it all by saying use gas or oil? ...

Bryan -
biomass - read http://www.greenbuildingforum.co.uk/forum114/comments.php?DiscussionID=6241&page=1#Item_0 for all the issues associated with it

BryanF

ah look, I'm not getting into this debate, yes I appreciate not all Biomass is sustainable or even that the best efficient use is as fuel. but it is the lesser evil when considering oil or gas. if you look at my subsequent post, I ask what the envelope spec and architect are recommending.

the OP is taking about underfloor heating, then were on to fuel sources and then geothermal which costs a lot and uses an incredible amount of plastic piping/ ground works.
People through no fault of their own, work backward from what their perceived comfort requirements are, and land on heating systems before looking at the actual problem which can be practically solved by good insulation,ventilation, orientation and supplemented by a small heat source such as a stove

I'm suggesting we minimise fuel use and try to find a local renewable source
the technology and building skills are available in Ireland to build with minimal heating systems in dwellings.

But all over this forum, including the OP, people are talking about heating systems and UFH at planning stage! in stead of minimising heat loss, energy consumption and getting their ventilation strategy correct. many of them are also self-builds not speculative developments meaning they will leaving in these homes probably for the rest of their lives. if we are 'advising them' shouldn't we be looking forward 50 years, trying to steer them towards 'zero energy in use buildings', low embodied energy construction and giving them real options to avoid fossil fuel consumption

if your building in a relatively rural area ( i presume most self-builds are), then generally timber can be sourced locally, if used efficiently in a properly designed home, there is no reason it cant be cheaper and more sustainable fuel than oil or gas

fclauson

Bryan - agreed

Everyone - sorry for diverting this onto a different subject

Insulate well, Ventalate appropriatly, then heat with consideration

Kristian_

bauney wrote: »

Hi, I'm doing a self build and planning is submitted but i'm not 100% sure what heating system to use. I've read lots on the web and on this forum but i don't know whats best.
I want underfloor heating(UHF) for obvious reasons. i.e. large open plan kitchen area, concrete floors upstairs, no rads on walls.......
From what i know, it appears oil/gas is very expensive for UFH. So i'm kinda swaying towards a heat pump (geothermal or aerothermal). I know installation costs are high here and electric costs are more severe but i feel its my best choice.

Has anyone any opinion on this as to what might be best? Is aero better than geo? What other alternative is there to heating UFH?

Regards

What option did you choose? We are beginning a self build and are trying to make a decision on what type of heating to go for. We have had a consultation with an expert on the various options and were quite bamboozelled afterwards!

No open fire with Geo

jprboy

Kristian_ wrote: »

No open fire with Geo

Wouldn't rule it out completely. There are devices you can get to stop the heat escaping up the chimney.

The Lone Ranger

Just to add to the debate. I had a visit from a geo sales man. He said that we could heat our house for 800euro a year including hot water in a 300 liter tank, house is 2900sqft with underfloor down and upstairs, with 150mm pumped cavity. He was selling a well pump system that requires 400 gallons of water per hour, sounds like a lot to me. Used water is then sent down a drain, away from the well. He said the cop would be over 5. Any one have experience of this. so many different view points.

Kristian_

The Lone Ranger wrote: »

Just to add to the debate. I had a visit from a geo sales man. He said that we could heat our house for 800euro a year including hot water in a 300 liter tank, house is 2900sqft with underfloor down and upstairs, with 150mm pumped cavity. He was selling a well pump system that requires 400 gallons of water per hour, sounds like a lot to me. Used water is then sent down a drain, away from the well. He said the cop would be over 5. Any one have experience of this. so many different view points.

That does sound like alot of water, are you going geo?

The Lone Ranger

Kristian_ wrote: »

That does sound like alot of water, are you going geo?

Yes, we are, but not sure which system yet. A heat pump seems to be our only option as oil would cost too much run and who knows how high the price of it will go.
Lots of conflicting info out there about geo, wish i could find someone it works ok for, then I would be more sure.

BryanF

are all ye guys putting in MVHR?

Condenser

The Lone Ranger wrote: »

Just to add to the debate. I had a visit from a geo sales man. He said that we could heat our house for 800euro a year including hot water in a 300 liter tank, house is 2900sqft with underfloor down and upstairs, with 150mm pumped cavity. He was selling a well pump system that requires 400 gallons of water per hour, sounds like a lot to me. Used water is then sent down a drain, away from the well. He said the cop would be over 5. Any one have experience of this. so many different view points.

Its illegal for a start. You must recharge any groundwater withdrawn, back into the ground via a dumpwell. The amount of water is about right. I'd avoid groundwater unless the water is crystal clear as maintainence of the filters can be a pain.
The COP will be over five but hes not including the well pump which will drag the COP back down.
Theres plenty of better ways to increase your COP than going water to water.

The Lone Ranger

BryanF wrote: »

are all ye guys putting in MVHR?

yes

Condenser wrote: »

Its illegal for a start. You must recharge any groundwater withdrawn, back into the ground via a dumpwell. The amount of water is about right. I'd avoid groundwater unless the water is crystal clear as maintainence of the filters can be a pain.
The COP will be over five but hes not including the well pump which will drag the COP back down.
Theres plenty of better ways to increase your COP than going water to water.

Illegal:eek:. Ok not going with him then. If not water to water what would you recommend.

Condenser

The Lone Ranger wrote: »

yes



Illegal:eek:. Ok not going with him then. If not water to water what would you recommend.

That would depend on the amount of ground available to you and the type of ground that it is. I'd need details of both in order to say which type of collector would suit you best and a bit more info on your insulation levels

The Lone Ranger

Condenser wrote: »

That would depend on the amount of ground available to you and the type of ground that it is. I'd need details of both in order to say which type of collector would suit you best and a bit more info on your insulation levels

Not sure if i have enough for horizontal, small back garden and would like a vegi patch. ground is 10" top soil followed by sand/gravel to a good depth. 100 quinn therm qw in floor, 140 graphit bead in cavity, roof 250 rockwool + 50 insulated plasterboard. windows, doors and ceilling with airtight tape.
thanks for the help

Carlow52

The Lone Ranger wrote: »

A heat pump seems to be our only option as oil would cost too much run and who knows how high the price of it will go.

How did you arrive at this conclusion.
You say the geo would cost u 800 pa to heat a 2900 sq foot house.
whats the capital cost, and expected life of ALL the gear?

I would guess 25 k and 5 years

Condenser

The Lone Ranger wrote: »

Not sure if i have enough for horizontal, small back garden and would like a vegi patch. ground is 10" top soil followed by sand/gravel to a good depth. 100 quinn therm qw in floor, 140 graphit bead in cavity, roof 250 rockwool + 50 insulated plasterboard. windows, doors and ceilling with airtight tape.
thanks for the help

Can you give me the dimensions of the garden because it sounds perfect for a horizontal loop. A DX system will give you the best COP. As long as the collector bed is sized properly and you're not drawing too much energy from the area, putting it under the veg patch wouldn't be a problem.

The Lone Ranger

Carlow52 wrote: »

How did you arrive at this conclusion.
You say the geo would cost u 800 pa to heat a 2900 sq foot house.
whats the capital cost, and expected life of ALL the gear?

I would guess 25 k and 5 years

Builder has just finished his own house, similar spec to ours but with oil condenser boiler. gone through 2 tanks already. He sayes oil is not a runner.

geo pump salesman said it would cost E800 pa to heat,(not me).

quote from that guy : 12k (pump and 300l water tank)

hope it would last longer than 5 years!

Condenser

Carlow52 wrote: »

How did you arrive at this conclusion.
You say the geo would cost u 800 pa to heat a 2900 sq foot house.
whats the capital cost, and expected life of ALL the gear?

I would guess 25 k and 5 years

If the Heatpump equipment is quality it will last 25yrs or longer. The UFH anywhere between 50 and 100yrs. The cheap air to water units available at the moment will last 7-10.

Condenser

The Lone Ranger wrote: »

Builder has just finished his own house, similar spec to ours but with oil condenser boiler. gone through 2 tanks already. He sayes oil is not a runner.

geo pump salesman said it would cost E800 pa to heat,(not me).

quote from that guy : 12k (pump and 300l water tank)

hope it would last longer than 5 years!

With the right system you'll heat it for less than €800

The Lone Ranger

Condenser wrote: »

Can you give me the dimensions of the garden because it sounds perfect for a horizontal loop. A DX system will give you the best COP. As long as the collector bed is sized properly and you're not drawing too much energy from the area, putting it under the veg patch wouldn't be a problem.

dont know exactly, the site is .33 hcts, with the house and garage set in the middle, front garden being bigger than the rear. also a 64sqm percolation area in the rear.

Condenser

The Lone Ranger wrote: »

dont know exactly, the site is .33 hcts, with the house and garage set in the middle, front garden being bigger than the rear. also a 64sqm percolation area in the rear.

Thats a pretty decent size site. Why not put the collector in the front garden?

The Lone Ranger

Condenser wrote: »

Thats a pretty decent size site. Why not put the collector in the front garden?

Firstly, thanks for all the info. I thought (I could be wrong) that the pump would have to be very close to the collection area. I had planned to have it in the garage and pipe it into the house in a (no loss) insulated pipe. How would i get around that, if indeed it is a problem.

Condenser

Once they are not ridiculously far away it doesn't have a huge impact on performance. I would however consider siting the unit in the house as the unit will be quiet and even the highly insulated pipes lose heat.

nulabert

Its illegal for a start. You must recharge any groundwater withdrawn, back into the ground via a dumpwell

I wouldn't entirely agree with that statement. Its more that you would probably need a discharge licence under the Water Pollution Act 1977 as amended. You would probably have to apply to your local Authority for the licence. These licences have an annual charge so more expense.

bruschi

The Lone Ranger wrote: »

Yes, we are, but not sure which system yet. A heat pump seems to be our only option as oil would cost too much run and who knows how high the price of it will go.
Lots of conflicting info out there about geo, wish i could find someone it works ok for, then I would be more sure.

I have a geothermal system. also have MHRV installed. heating of the house is perfect, and house is pretty much air tight and well insulated. those were the first 2 priorities, and wanted to get away from oil based system. UFH is great balance of heat throughout a house, much prefer it to rads. needed an area of roughly 30m x 10m for the geo pipework, its about 10m away from the house, but had the area for it so there was no issues there. average costs seem to be around the mark quoted by someone there earlier in the thread, around 1600 or so per year.

fclauson

the price for running any of these systems must be based on how much heat is leaking out of the house - regardless of the systems used - if insulated right it will use very little heat input to maintain the right temp

• with oil - its cheap to install but then you are open to oil price changes
• with GSHP - its expensive to install but the argument is that its cheaper over the life of the system to run (althought electricicty is not cheap nor green)

look at http://www.seai.ie/Publications/Statistics_Publications/Fuel_Cost_Comparison/

if you can get your heat demand low - then the above becomes a bit academic - happy to help with a simple PHPP type calculation - this will give you the demand which if you insulate right should be about 10W/M2/Annum (most heat engineers work on a figure of 20 or 30)

In order of importance
a) design the house you want
b) get good wall/floor/roof make up to get a reasonable U value
c) eliminate as much cold bridging as possible
d) put in good windows - balance price vs value - tripe glaze would be my recommendation
e) make the whole house as airtight as possible (more heat can be lost due to poor air tightness than to a slightly worse off U value)
f) finally work out how you want to heat it

Francis

fclauson

The Lone Ranger wrote: »

Builder has just finished his own house, similar spec to ours but with oil condenser boiler. gone through 2 tanks already. He sayes oil is not a runner.

Just see the above - may I hazard a guess that its either not insulated right or its not airtight right :mad: read my note above - a house heat demand is simple to work out - but the house has to be built right to perform right