Cost of Heating with Wood versus Coal or Oil

Jack180570

I'm looking for feedback/information regarding the cost of domestic heating with wood as against coal or oil. I am also interested in broadening the discussion beyond the quantitative into the qualitative issues such as...
What are people's experiences with wood heating?
What are the pros and cons of wood heating?
How many people out there heat their homes with wood only?
Why do some people combine various solid fuels with wood?
How should wood fuel be sold, weight or volume?
How important is moisture content of firewood to users?
For people reading this thread who are not using wood to heat part or all their home. .. what reasons stop you heating with wood?
Please add whatever else you feel is relevant and interesting.
Thank you.

fclauson

check out
http://www.seai.ie/Publications/Statistics_Publications/Fuel_Cost_Comparison/

also couple of things of wood -
yes it needs to be dry/seasoned - you will waste a lot of energy drying it in the fire if its still wet
depending how and where you purchase it will depend on if its econmic

F.D

Reasons for looking at wood heating for me would be the fact oil has doubled in price since i moved into my home,
also we are farming now so in the long term have potential to gather/grow our own fuel
Reasons against doing it would be overall cost of putting in a semi/fully automated system to give you the flexability of oil
15k for a state of the art log burning system is a lot of money and you still have to feed it, build a shed for it i assume Woodchip systems are similar
I am still looking at all these options and with advice from different people like teepee on here it shines a better light on these systems

I think for it to be a winner over oil it has to be in log form, the more its processed wood chips/pellets the closer it will be in price to oil and save you very little

gutteruu

We installed a stove with back boiler a year ago and have tried nearly all the fuels and worked out costs. That SEAI doc posted matched almost exactly with my figures. Wood varies so much depending on type of wood and moisture content. The logs we bought in September were almost useless, but now they are dried out properly they are as good as any briquettes, turf etc.

The big thing for me is the labour involved. If you have to drag 200 bags of turf from a trailer to a shed, to the cupboard, then to the fire is a lot of work and puts crap all over the house. Briquettes slightly less work, wood about the same and coal is easiest.

I think there figures are wrong on electricity. I reckon it is just as cheap as any other fuel.

MOTM

gutteruu wrote: »

I think there figures are wrong on electricity. I reckon it is just as cheap as any other fuel.

Fuel cost/kWh is only half the battle. You also need to consider the appliance efficiency. Direct electric heating would be much more efficient (~100%) than say, an open fire (~30%). So for every kWh of electricity bought, you've to buy about 3kWh coal/wood/oil in the open fire. If you'd an efficient solid fuel appliance (say 75-80%) then it would be cheaper to run than an electric appliance running from day-rate electricity.

MOTM

To answer the questions asked, from my own experience (with 2 solid fuel stoves, an oil boiler, and solar water heating):

Jack180570 wrote: »

What are people's experiences with wood heating?

I prefer it from the sustainability point of view, and find it burns at a more suitable temperature than coal when using a stove. Coal is too hot.

Jack180570 wrote: »

What are the pros and cons of wood heating?

It is possible to get it cheap, but only in large volumes. If you've to buy it in bags, piecemeal, then this is expensive, unpredictable and often too wet to use.

Jack180570 wrote: »

How many people out there heat their homes with wood only?

No idea. I use it for the sitting room and living room primarily, and oil for the remainder of the house. Solar gets priority over oil for water heating in our system.

Jack180570 wrote: »

Why do some people combine various solid fuels with wood?

I only use coal to get the stove going, then its wood for the rest of the night. In an open fire, you could go through a lot of dry wood given the lack of draught control.

Jack180570 wrote: »

How should wood fuel be sold, weight or volume?

I think by volume. If its by weight, you are very dependent on moisture. The "wet" part of wood is of no use to you. The volume stays the same no matter how wet it is.

Jack180570 wrote: »

How important is moisture content of firewood to users?

Vital. And from my own experience, its where sellers are most inclined to be economical with the truth. "Tis grand and dry" etc. The only way around this is to buy in bulk and ensure you have it long enough to guarantee that it is seasoned properly.

Jack180570 wrote: »

For people reading this thread who are not using wood to heat part or all their home. .. what reasons stop you heating with wood?

Doesn't include me (yet).

Capt'n Midnight

gutteruu wrote: »

I think there figures are wrong on electricity. I reckon it is just as cheap as any other fuel.

If this were true we'd all be running storage heaters on half price night rate electricity.

Electricity is handy if you have a fan heater or infra red heat lamps, it's instant warmth where you want it. It's also hand for top-up heat or taking the chill out of a room.

But it's mainly apartment dwellers who don't have access to fossil fuel who use electricity as the sole means of heating.

muffler

Just to add that following PM contact with Jack180570 I can confirm that while he is involved in the wood fuel provision business this thread is not being used for promotional purposes and has been approved by the forum moderators as we hope it will be helpful to others in making informed choices on the costs and benefits of different heating products.

Jack180570

fclauson wrote: »

check out
http://www.seai.ie/Publications/Statistics_Publications/Fuel_Cost_Comparison/

also couple of things of wood -
yes it needs to be dry/seasoned - you will waste a lot of energy drying it in the fire if its still wet
depending how and where you purchase it will depend on if its econmic

Thanks for that fclauson... I have looked over the seai link above and a few observations...
1. it does not have any category for 'split firewood'. It has wood briquettes which from looking at the Gross Calorific Value (GCV) per Kg of 4.8kW/hr appears to be exactly as they say, a wood briquette rather than split firewood.
2. The sheet uses GCV rather than the Net CV of the fuels. As much as I can understand from looking at published material in other European Countries where wood heating is much more common, NCV is the metric that should be used rather than GCV.

I totally agree that the firewood should be dry/seasoned. Here again from research and talking to suppliers and users of stoves, the firewood should be 20% MC (wet basis) or less. Yes the appliances can burn up to 25, even 30% MC firewood, but the result is less heat and a dirier stove and flue.

On the cost of firewood I think that it is not a transparent market. If you want to know the price of heating oil there are a number of internet websites and even the back of the Farmers Journal that publish weekly prices. I think this is something that is lacking in the firewood market and I think it is discouraging people from using firewood for heating their houses.

Jack180570

F.D wrote: »

Reasons for looking at wood heating for me would be the fact oil has doubled in price since i moved into my home,
also we are farming now so in the long term have potential to gather/grow our own fuel
Reasons against doing it would be overall cost of putting in a semi/fully automated system to give you the flexability of oil
15k for a state of the art log burning system is a lot of money and you still have to feed it, build a shed for it i assume Woodchip systems are similar
I am still looking at all these options and with advice from different people like teepee on here it shines a better light on these systems

I think for it to be a winner over oil it has to be in log form, the more its processed wood chips/pellets the closer it will be in price to oil and save you very little

Thanks for that FD...
I think that cost is probably the biggest motivator for most people looking at heating with wood fuel. The immediate biggest drawback for a lot of people is the cost of the equipment, be it a dry stove, stove with backboiler, gasifier log burner. I also think that as much as there is a lack of transparency and information on the cost of the fuel, there is a lack of good widespread knowledge of appropriate systems. In a way it is ironic that one of the best sources of knowledge is here on boards.ie.

I guess that wood heating here is in its infancy and as all the associated problems of an industry that is at that stage of development. Having said that, wood heating is a mature technology and it seems that some of the best information resources are from Europe where the industry is far more developed.

I think that woodfuel in log form is very accessible and for a consumer is 'safe' - having said that, I think the most important aspect is that the woodfuel is appropriate to the consumers situation, space, lifestyle etc.

One of the best information handbooks I have come across so far is to be found here http://nuke.biomasstradecentres.eu/Portals/0/D2.1.1%20-%20WOOD%20FUELS%20HANDBOOK_BTC_EN.pdf
If the link above does not work you can find it by going to this website biomasstradecentres.eu/ and selecting the first download in the 'deliverables' tab. I think that the model they propose is what we need to strive to achieve here in Ireland.

Jack180570

gutteruu wrote: »

We installed a stove with back boiler a year ago and have tried nearly all the fuels and worked out costs. That SEAI doc posted matched almost exactly with my figures. Wood varies so much depending on type of wood and moisture content. The logs we bought in September were almost useless, but now they are dried out properly they are as good as any briquettes, turf etc.

The big thing for me is the labour involved. If you have to drag 200 bags of turf from a trailer to a shed, to the cupboard, then to the fire is a lot of work and puts crap all over the house. Briquettes slightly less work, wood about the same and coal is easiest.

I think there figures are wrong on electricity. I reckon it is just as cheap as any other fuel.

Thanks for your post Gutteruu..
I agree with you that there is way too much variability in the quality, MC and price of firewood and it makes it very hard for the consumer to quantify if he/she is getting value or not.

From the research I have done I believe that heating with woodfuel in a modern stove is more economical than oil on the basis of fuel cost. Obviously if someone is currently heating with oil only and has to fund the cost of a stove and installation of the stove, then there is going to be a payback period that has to be taken into account.
For people currently using coal in a modern multifuel stove then that equipment cost is not there but coal and firewood are closer in price and I dont know which is cheaper.

I totally agree that heating with firewood, all solid fuels in fact, is a huge change from heating with oil. Oil is so convenient, flick the switch and you have heat. With solid fuels it is a complete change, its almost a lifestyle change.

I would like to think that woodfuel heating is the 'best' of the solid fuel options.
It is carbon neutral (not 100% carbon neutral as there is a certain amount of energy used in the processing and delivery of the fuel, but its carbon footprint is a fraction of what the other fuels are).
It is clean (much cleaner to handle and if for example you burn it in a stove using firewood only, the ash content is maybe1-2% and you will only have to remove the ashes every 1-2weeks, also if it is good dry firewood in a modern dry stove you will have no soot in the firebox and no tar or creosote in the chimney).
I am unsure if it is cheaper than coal and I guess that part of the purpose of this thread is to try to get peoples opinions on this.

Jack180570

MOTM wrote: »

Fuel cost/kWh is only half the battle. You also need to consider the appliance efficiency. Direct electric heating would be much more efficient (~100%) than say, an open fire (~30%). So for every kWh of electricity bought, you've to buy about 3kWh coal/wood/oil in the open fire. If you'd an efficient solid fuel appliance (say 75-80%) then it would be cheaper to run than an electric appliance running from day-rate electricity.

Thanks for that MOTM...
Yes I would agree with you that the efficiency of the solid fuel appliances have a huge impact on the economics of heating with solid fuel and open fires are a very very wasteful way of domestic heating.
Having said that, we have to have some basis by which to make decisions and try to calculate the value of heating fuels.
From my research to date and based hugely on this handbook http://nuke.biomasstradecentres.eu/Portals/0/D2.1.1%20-%20WOOD%20FUELS%20HANDBOOK_BTC_EN.pdf
It seems to suggest that to give consumers the best information on cost/value of fuels that the Net Calorific Values of the various fuels should be used as the basis for comparisons. Thereafter each consumer will have to then calculate the efficiency of the appliance in which the fuels will be burned.

Jack180570

MOTM wrote: »

To answer the questions asked, from my own experience (with 2 solid fuel stoves, an oil boiler, and solar water heating):


I prefer it from the sustainability point of view, and find it burns at a more suitable temperature than coal when using a stove. Coal is too hot.



It is possible to get it cheap, but only in large volumes. If you've to buy it in bags, piecemeal, then this is expensive, unpredictable and often too wet to use.


No idea. I use it for the sitting room and living room primarily, and oil for the remainder of the house. Solar gets priority over oil for water heating in our system.


I only use coal to get the stove going, then its wood for the rest of the night. In an open fire, you could go through a lot of dry wood given the lack of draught control.



I think by volume. If its by weight, you are very dependent on moisture. The "wet" part of wood is of no use to you. The volume stays the same no matter how wet it is.



Vital. And from my own experience, its where sellers are most inclined to be economical with the truth. "Tis grand and dry" etc. The only way around this is to buy in bulk and ensure you have it long enough to guarantee that it is seasoned properly.


Doesn't include me (yet).

Thank you MOTM for that really detailed reply.
I have no experience of burning coal but that is interesting to hear.
I too like the sustainability element of wood fuel, not only from the climate change aspect but also from the economic aspect (so long as its not imported woodfuel), in that it really is a local business and has the potential to generate local jobs but also begin to replace our huge oil import bill (I think I read somewhere we import c, €7billion worth each year). Also I think that if it is done correctly it should be cheaper cleaner and more sustainable than oil/coal etc.

I think that the 'only cheap in big volumes' is one of the unfortunate aspects of the wood heat/firewood market currently. The model for wood heat in countries like Austria and Germany seem to be developing along the lines of biomass centres selling high quality woodfuel where people have confidence in quality of the product, where it is competetively priced can be collected or delivered and where it is within 30km of you, where you can visit and see the process, where they have long opening hours, effectively a biomass supermarket - I think this is what we need here in Ireland so as to give confidence and quality product to the consumers.

I think if we had a network of biomass trade centres in Ireland that it would solve a lot of the quality issues on the supply side.

Regarding quality of firewood, in Ireland we now have a quality assurance scheme/standard for firewood and woodchip. The website for further information is http://wfqa.org/
Only a few suppliers are registered so far but it appears to be a good scheme and I am sure that it will grow as time goes by and any supplier that is serious about his/her business will register and operate to the standards required. It will increase the professionalism on the supply side. Requirements include not only correct labeling and MC% but also, insurance, H&S requirements, financial/taxation requirements etc. so no fly-by-night operators will be on this list!

Jack180570

http://nuke.biomasstradecentres.eu/Portals/0/D2.1.1%20-%20WOOD%20FUELS%20HANDBOOK_BTC_EN.pdf

This handbook is a great source of information on woodfuel heating. It was funded by the EU and the aim of the project (from which the handbook above is just one publication) was, in their own words...
...to set up Biomass Logistics and Trade Centres (BL&TC)which would be .... regional service stations for top-quality fuels, run by local farmers/forest entrepreneurs... adding value for the farmers and customers who benefit from the bundled, high-quality local supply of wood fuels... enhanced further by comprehensive services such as delivery of fuel or competent advice... on wood fuels... Through a network of these BL&TC customers can be sure that supplies are guaranteed over the long term, cost-effective and environmentally friendly.. supporting local economies... improving the confidence of customers about the local availabilty of wood fuels of proper quality and encouraging the installation of new modern wood heating systems....

Anyhow... they say NCV is the appropriate metric with which to measure the amount of energy in different fuels. NCV is measured in kWh and is equivalent to 1 unit of electricity so it is a familiar unit to all of us. They then go on to give the following 'energy equivalences' of various fuels.

Heating oil - 10kWh/litre
Coal - 7.67kWh/kg
Wood 20% MC wb - 4kWh/kg

In summary they say -
1 litre of heating oil is approximately equal to 2.5kg wood (hardwood or softwood @20% MC wb.

Food for thought...

Capt'n Midnight

off topic
just wondering if anyone knows offhand what % of wood pellets are imported ?

MOTM

Jack180570 wrote: »

It seems to suggest that to give consumers the best information on cost/value of fuels that the Net Calorific Values of the various fuels should be used as the basis for comparisons. Thereafter each consumer will have to then calculate the efficiency of the appliance in which the fuels will be burned.

Bear in mind that
1) the fuel bought has moisture in it, and therefore the GCV corresponds to the weight of the fuel. NCV kWh/kg implies it is net of moisture. If buying seasoned timber here by weight, you're more likely to be quoted for the cost per unit total weight rather than net of moisture....so on that basis should GCV be used rather than NCV? That said, if buying from the guy on a smallads website or local paper/noticeboard, you'll be quoted in terms of rough trailer size. "Tis a grand big car trailer, very deep" etc. Hard to get a quote by weight from these guys.

2) Most consumers (and I would suggest a lot of people in the industry) don't know the difference between NCV and GCV. If using costs based on NCV, the efficiency also needs to be on the same basis. If for example, they use the HARP or SEDBUK databases (as you would for Irish TGD L compliance or for any DEAP/SAP assessment) you'd need to operate on a GCV basis.

Jack180570

MOTM wrote: »

Bear in mind that
1) the fuel bought has moisture in it, and therefore the GCV corresponds to the weight of the fuel. NCV kWh/kg implies it is net of moisture. If buying seasoned timber here by weight, you're more likely to be quoted for the cost per unit total weight rather than net of moisture....so on that basis should GCV be used rather than NCV? That said, if buying from the guy on a smallads website or local paper/noticeboard, you'll be quoted in terms of rough trailer size. "Tis a grand big car trailer, very deep" etc. Hard to get a quote by weight from these guys.

2) Most consumers (and I would suggest a lot of people in the industry) don't know the difference between NCV and GCV. If using costs based on NCV, the efficiency also needs to be on the same basis. If for example, they use the HARP or SEDBUK databases (as you would for Irish TGD L compliance or for any DEAP/SAP assessment) you'd need to operate on a GCV basis.

Hi MOTM and thanks for that.
All firewood bought contains moisture because wood is hygroscopic and 0%MC is not the equilibrium moisture content of the air. Now the most simple explanation of the difference between GCV and NCV I found, is at http://wiki.answers.com/Q/Why_is_net_calorific_value_is_less_than_gross_calorific_value This attempts to answers th question as to why GCV is higher than NCV, the reply being:
NCV - the lower calorific value or Net calorific value (NCV) which supposes that the products of combustion contain the water of combustion to the vapor state. The heat contained in this water is not recovered....
GCV - the higher calorific value or Gross calorific value (GCV) which supposes that the water of combustion is entirely condensed. The heat contained in this water is recovered.'

Basically as I understand it, the NCV should be used when calculating the heat value of firewood because with NCV, the amount of energy required to 'boil off' the moisture in the wood is subtracted from the total or GCV. This is important, necessary and correct to do so, because this energy is lost up the chimney because it cannot be recovered by condensing. If you were to use the GCV I believe that you would be overestimating the heat value of the firewood.
On page 25 Fig 2.8.2 it shows how the NCV of wood varies with different MC% as follows:
MC0 - oven dry wood - 5.14kWh/kg
MC10 - approx MC% of pellets - 4.6kWh/kg
MC 20 - ideal MC% for firewood in stoves/gasifiers - 4.0kWh/kg
MC30 - usual MC% of small scale wood chip plant - 3.4kWh/kg
As you can see, as the MC% increases the heat value decreases. I think therefore that NCV should be used. Also it is the more conservative figure.

I totally agree with your comment regarding the information provided by people who are selling via small ads websites and local ads. Net bags, nut bags, builder bags, various descriptions of trailer loads... the information given is so general and non-descript that it makes it impossible for the buyer to know what they are getting. I believe that it is totally unsatisfactory for the buyers.
I believe that it is also very damaging to the firewood business for both the buyers and sellers and gives little confidence to a buyer that if he/she installs a dry stove/boiler stove or gasifer, he/she will be able to get a reliable, high quality supply of woodfuel at a proper/correct price.

Regarding you second point I totally agree with you, and in addition I believe that most of the sellers have little interest so long as they can sell their product. Also on the consumer side I believe that there remains much to be learned. I recently had the experience of being in a house where coal and wood was being burned in a back-boiler stove. Being curious by nature I had to examine the firewood and found very well seasoned spruce and some ash that must have been cut down just the day before. Enquiring from the person of the house as to what they thought of the ash versus the spruce, the answer was that the ash was brilliant as it would last forever in the fire on top of the coal.

I must admit that I do not have a detailed knowledge of the HARP or SEDBUK databases. I am however surprised that more of the stoves that are on sale here in ireland, who have quoted efficiency figures are not on these databases. Slightly more worrying is the fact that a manufacturer is quoting 82.4% efficiency for a stove that on the Harp database is quoted at '75% seasonal efficiency'. Maybe its something to do with the NCV versus the GCV?

sas

Jack180570 wrote: »

Enquiring from the person of the house as to what they thought of the ash versus the spruce, the answer was that the ash was brilliant as it would last forever in the fire on top of the coal.

Had to laugh at this one, my parents are exactly the same. It appears to be a commonly held opinion, timber that is wet and will sit in the hearth smoldering away for hours is great!

MOTM

Jack180570 wrote: »

............
Basically as I understand it, the NCV should be used when calculating the heat value of firewood because with NCV, the amount of energy required to 'boil off' the moisture in the wood is subtracted from the total or GCV. This is important, necessary and correct to do so, because this energy is lost up the chimney because it cannot be recovered by condensing. If you were to use the GCV I believe that you would be overestimating the heat value of the firewood.
.......
............

I must admit that I do not have a detailed knowledge of the HARP or SEDBUK databases. I am however surprised that more of the stoves that are on sale here in ireland, who have quoted efficiency figures are not on these databases. Slightly more worrying is the fact that a manufacturer is quoting 82.4% efficiency for a stove that on the Harp database is quoted at '75% seasonal efficiency'. Maybe its something to do with the NCV versus the GCV?

The DEAP manual has a short summary of NCV/GCV: "
The calorific value of a fuel is the heat released when one kilogram of the fuel is burnt completely in excess air, under specified conditions, and the combustion products cooled back down to the initial (room) temperature. If the water vapour in the combustion products remains as vapour, the heat released is the "net calorific value", but if it is condensed to liquid water, releasing its latent heat of vaporisation, the total heat released is the "gross calorific value".
"

The gross efficiency will be lower than the net efficiency and this is likely the cause of manufacturers quoting higher efficiencies. You'll see some condensing boiler manufacturers quoting net efficiency at > 100%. What counts is that the calculation of energy use is comparing eggs with eggs. If working on GCV basis you use the gross efficiency.

On HARP, its up to the supplier or manufacturer to get themselves listed I think. If they have the test data available, then listing on HARP is free. They can provide (accredited) test data to BER assessors alright, but it would need to be converted (DEAP talks about this) to gross efficiencies if not done so already.

Jack180570

MOTM wrote: »

The DEAP manual has a short summary CV/GCV: "
The calorific value of a fuel is the heat released when one kilogram of the fuel is burnt completely in excess air, under specified conditions, and the combustion products cooled back down to the initial (room) temperature. If the water vapour in the combustion products remains as vapour, the heat released is the "net calorific value", but if it is condensed to liquid water, releasing its latent heat of vaporisation, the total heat released is the "gross calorific value".
"

The gross efficiency will be lower than the net efficiency and this is likely the cause of manufacturers quoting higher efficiencies. You'll see some condensing boiler manufacturers quoting net efficiency at > 100%. What counts is that the calculation of energy use is comparing eggs with eggs. If working on GCV basis you use the gross efficiency.

On HARP, its up to the supplier or manufacturer to get themselves listed I think. If they have the test data available, then listing on HARP is free. They can provide (accredited) test data to BER assessors alright, but it would need to be converted (DEAP talks about this) to gross efficiencies if not done so already.

Thanks for that detail MOTM...
You seem to have a very detailed knowledge of CV and stove efficiency. Would it be possible for you to work through the figures for M20 firewood v oil burned in a couple of different stove types.
Fuel, 1kg M20, 4kW/h per kg NCV.
Kerosene, 1 litre, 10kW/h per litre NCV?
Firewood burned in (a) modern high efficiency stove, , and (b) burned in an older stove.
Kerosene burned in a modern condensing oil boiler and secondly in an older ordinary oil boiler.

If you could choose the approx correct efficiency figures, both gross and net for the various boilers then it would give all of us an idea of the valve of firewood V oil depending on the type of boiler we already have. For people who are looking to buy a new boiler it would be very helpful I imagine.

Thanks again

MOTM

Jack180570 wrote: »

Thanks for that detail MOTM...
You seem to have a very detailed knowledge of CV and stove efficiency. Would it be possible for you to work through the figures for M20 firewood v oil burned in a couple of different stove types.
Fuel, 1kg M20, 4kW/h per kg NCV.
Kerosene, 1 litre, 10kW/h per litre NCV?
Firewood burned in (a) modern high efficiency stove, , and (b) burned in an older stove.
Kerosene burned in a modern condensing oil boiler and secondly in an older ordinary oil boiler.

If you could choose the approx correct efficiency figures, both gross and net for the various boilers then it would give all of us an idea of the valve of firewood V oil depending on the type of boiler we already have. For people who are looking to buy a new boiler it would be very helpful I imagine.

Thanks again

I’m more used to working on a GCV basis so will stick with that here (also, I’m a bit caught for time / couldn’t be bothered working in NCV). Feel free to point out any errors in the calculation below – I haven’t double checked it. I haven’t given any consideration to level of controls etc. I’m just assuming 1000kWh needed out of the appliance – no account for rads/underfloor/heating a room from a stove.
GCV basis helps when using the oil(gross) costs on the SEAI fuel cost comparison, the DEAP (gross) conservative default efficiencies and the HARP (gross) appliance efficiencies. I don’t have anything like an accurate estimate of wood logs costs (who does??) so will assume pellets from the fuel cost comparison.
Fuel cost comparison says wood has 4.8kWh/kg and cost is €0.25/kg
Fuel cost comparison says Kerosene has 10.18 kWh/L and cost is €0.9/L
To provide 1000kWh (GCV) heat using a 60% stove (typical low efficiency, DEAP table 4a) requires 1666kWh. Divide by 4.8= 347kg. Multiply by .25 = €86 for 1000kWh heat output
HARP (http://www.seai.ie/Your_Building/BER/BER_Assessors/Technical/HARP_Database/Solid_Fuel_Room_Heaters/ ) shows stoves up to 80% efficient. So cost for 1000kWh heat would be (86*60/68) = €64
To provide 1000kWh (GCV) heat using a 70% oil boiler (typical low efficiency, DEAP table 4b) requires 1428kWh. Divide by 10.18= 140L. Multiply by .9 = €126 for 1000kWh heat output
HARP has boilers up to about 97% efficiency. So cost for 1000kWh heat would be (126*70/97) = €88

Quicker way to do the calcs above is to go straight from kWh required and cost/kWh to fuel cost…. I left the detailed steps above in so do your own calc on NCV basis using the parameters you’d given.

Oil is more costly on the basis of my simple calculations, but when responsiveness and controls are taken into account its a different ballgame (at a guess).

Irish Steve

Interesting thread, now from a potential consumer point of view, some thoughts.

We at present have oil, the boiler is 20 or so years old, the burner was replaced after flood damage in 2002, standard radiators, and an external heat exchanger for hot water, while there's an immersion in the tank, we use oil all year round, if nothing else, it keeps the boiler pump etc moving. All the rads are on TRV's, 2 zones, and the DHW is thermostatically controlled, the boiler is demand only, if there's no heat required, it won't fire. There is also for absolute safety a frost stat in the boiler house just in case it gets seriously cold.

The house is a detached dormer bungalow, 2100 sq ft ground floor, 900 upper, so not small, built in 1990, so also not particularly well insulated, the biggest problem being that it's not a warm roof construction, and the builder didn't do anything like the job he should have done on insulation, I did an upgrade job, but I know it's far from good at this stage.

So, I've thought long and hard about wood, there are a number of issues that need to be addressed before I can even think about putting anything in.

First, I have to get the house decently insulated, which means improving the cavity wall insulation, and the roof has to be sorted so that we don't lose significant heat through wind loss. If it snows, and there's little wind, not a lot melts on the roof, so we're not losing that much, especially compared to many of the houses around us, but where we are badly hurt is when it's windy, due to a total lack of insulation under the dormer floor, and at the edges. The fibre glass is now getting old, and compacted, so needs to be sorted. That's not a small job, and not cheap either.

There's some insulation in the cavities, but I don't think it was done particularly well, and it certainly is below current standards. The windows are double glazed, but I am guessing that if nothing else, the glass units need to be upgraded, the specs now seem to be higher than they were.

If I want to go wood, rather than oil, (I could go gas, but they want silly money to connect to the main at the end of our drive, as it's 50 metres away, and even sillier money to change the jets in the LPG appliances) the first issue is to make sure that I'm sizing it right.

The more significant issue for me is wood supply. I don't see any realistic supplies in this area (South Meath), I see odd adverts for a trailer of wood, but there's no information about what that represents in terms of weight, quality, moisture content, type of wood or size, and storage is another issue, at present, I don't have suitable storage for a large quantity of wood.

Then there's the aspect of managing the wood supply. A few years ago, there was talk that wood chip, or pellet, would be available in bulk, delivered in a similar manner to the way that cement or flour is delivered, in bulk, transferred into the storage by air. I've yet to see that happen in a practical manner, and while I would have considered 25 Kg bales of pellet a few years ago, at the age of nearly 62, I've come to the conclusion that humping 25 Kg bags of any sort around the place is going to lose its appeal before too long, 25 Kg bags of salt for the water softener are bad enough and they are only once a month, pellets will be a lot more often.

Then there's the continuity of supply, which is worrying right now, I don't see a national distribution system for wood chip in the way that oil, or coal is distributed. In fact, it's the opposite, if I want wood chip, I have to go google searching for it, and I may or may not find suppliers. The final worry is price. It seems to be very unpredictable, and from comments I've seen on here, to me, wood is too close to the price of oil right now, and I'm not convinced that the price for wood is because of the cost of the material and transport, my fear is that it's that close to oil due to profiteering by the limited number of suppliers that are active, as long as they are cheaper than oil, or coal, the product will sell.

Realistically, the biggest problem is that the Govt has its head in the sand on energy policy, the Greens just muddied the waters with their intellectual and impractical attitudes, and the FG/Labour Govt seems to have forgotten about the problems that the country is facing with their total absence of visibility on anything to do with energy, at the moment, it suits them that people still burn oil, as that's taxed to the hilt, so helping them get the financials sorted.

So for wood to be viable for me, I first have to find a significant investment to upgrade the infrastructure of the house to make wood worth installing, and then find the significant cost for the changes to the heating system to put wood in, and right now, that's not going to be easy, the events of recent years have hurt us badly, both short term and long term. That change will only be worth making if there are significant savings to be made that justify the install cost, otherwise I might just as well stay with oil.

The SEAI grants for upgrades are a small help, but not much, and finding the extra to make the change will not be easy for some time to come.

Having long term confidence in continuity of supply is also a major factor, and the final issue is the management of the system once it's installed, while at the age of 20 I'd be happy to hump wood about the place, that's not an option any more.

So, while in theory wood is an option, in practise, its an uncertain unknown, and it will only take a major shortage of wood for almost any reason to cause significant problems, switching back to oil at short notice will be expensive to do.

It may well be that I need to look more closely at making the house a lot more energy efficient, and going towards a heat pump based system, along with finding a way to be able to use off peak electricity during the day, but that's easier said than done unless I want to go towards underfloor heating, which is not going to be easy on a 2000 sq ft concrete ground floor that's tiled throughout.

In a nutshell, wood as a central heating fuel in a high efficiency stove is effectively a new concept for most people, and it's not taken off in the way that it needs to for people to be comfortable with it. Some of the early boilers have been less than spectacular performance and reliability wise, which may also be a wood quality issue, but either way, the reputation has suffered.

If wood is to become an acceptable alternative to oil, or gas for that matter, its going to require some significant support from government in a number of areas, to get it to the point where it has the critical mass to be viable, right now, I don't see it as being a mainstream fuel, its still sittting at the fringe, and seen by many as a "green" but fringe option that's best left to the trendies that are committed to the green agenda. To become a viable alternative to the major fuels needs support from the top, in terms of installation, supply and distribution. Maybe then, things will improve.

BryanF

Irish Steve wrote: »

So, while in theory wood is an option, in practise, its an uncertain unknown, and it will only take a major shortage of wood for almost any reason to cause significant problems, switching back to oil at short notice will be expensive to do.

you know the same could be said for Oil? think 1973..