Cost Saving of Wood Burner (kw/h gas consumption reduction v's cubic meters of wood burnt).

PeteTheMoneySaver

I am considering the pro's and cons of getting a wood burner fitted to offset the cost of gas central heating (which I intend to keep).

The only option I have available to me is an inset wood burner, as opposed to a free standing one. The inset wood burner would be installed into the space vacated by our old gas simulation fireplace at the bottom of a chimney stack on a double brick outside wall.

Discussion thoughts 1./

If properly insulated, how economical would a modern inset wood burner be compared to a free standing one that is not inset of course?

Discussion thoughts 2./ 

Has anyone done a cost analysis over a year before and after the fitting of a wood burner? i.e. gas usage drop in kw/h, against the amount of wood burnt in cubic metre's. I ask the question in terms of quantity of fuel burnt rather than the cost of the fuel because the price of wood and and especially gas, are subject to fluctuation and could therefore skew results considerably. I realise any results are dependant on type of wood burnt(and how well seasoned), how efficient your burner is, whether it's an inset burner or not, and maybe whether it's set in/on an outside wall. However,  it would be useful to a have a rule of thumb if anyone has ever analysed this for themselves. Fundamentally, I am trying to assess if I can save enough money to claw back the cost of fitting the wood burner over a number of years, and how many years that might take. I intend to use the wood burner enough to burn through 3 cubic meters of firewood per winter which I can buy for £340.

Discussion thoughts 3./

I realise hardwood takes longer than softwood to season. Presumably, hardwood burns for longer than softwood, and therefore in theory provides better economy on a cost/burn time basis. If this true, has anyone had experience with both types of wood and been able to draw any conclusion regarding the comparative number of hardwood /softwood logs burnt over a set period?

Moneysavingchap

Discussion point 4 - the particulate matter given off by wood burners is harmful to your health. I personally wouldn't touch a wood burner with a barge pole. 

The less things being burnt in your home the better. I do have a gas boiler but that is significantly cleaner and I don't sit directly around it of an evening. 

Swipe

It will be hands down more expensive if you need to buy wood. No cost analysis required and just a matter of time before stoves are outlawed by the green brigade. I wouldn't waste your money and not worth the mess that comes with them. I've stopped using mine. 

maisie_cat

Moneysavingchap said:

Discussion point 4 - the particulate matter given off by wood burners is harmful to your health. I personally wouldn't touch a wood burner with a barge pole. 

The less things being burnt in your home the better. I do have a gas boiler but that is significantly cleaner and I don't sit directly around it of an evening. 

I have a particulate matter monitor in my living room 2 metres from the stove and it never registers outside the green zone. Burning properly seasoned dry wood is the key, as is being aware of how to use a stove properly.
We are lucky that we have access to free wood as a product of having to fell diseased trees, buying wood is expensive.
Having said that, if I had mains gas I would use it, it's cheaper per kWh than wood, we have a wood pellet boiler which is very efficient wood and it costs 12.5p/kWh now, but was15p/kWh a couple of months ago compared to gas at 9p?

Qyburn

Swipe said:

It will be hands down more expensive if you need to buy wood. No cost analysis required and just a matter of time before stoves are outlawed by the green brigade. I wouldn't waste your money and not worth the mess that comes with them. I've stopped using mine. 

That depends on the price of wood locally. We buy maybe half of what we use, and the cost for bought-in firewood aro7nd here is just a bit less per kWh than oil, so much less than mains gas.

The other factor is the popular subject of "resilience", and specifically the guidance nowadays that we need to plan for power cuts like we've had in the last two winters. Having a stove as supplementary heating makes a lot more sense that having a 10kW generator to keep an all-electric house operational.

Swipe

Qyburn said:

Swipe said:

It will be hands down more expensive if you need to buy wood. No cost analysis required and just a matter of time before stoves are outlawed by the green brigade. I wouldn't waste your money and not worth the mess that comes with them. I've stopped using mine. 

That depends on the price of wood locally. We buy maybe half of what we use, and the cost for bought-in firewood aro7nd here is just a bit less per kWh than oil, so much less than mains gas.

The other factor is the popular subject of "resilience", and specifically the guidance nowadays that we need to plan for power cuts like we've had in the last two winters. Having a stove as supplementary heating makes a lot more sense that having a 10kW generator to keep an all-electric house operational.

The cost of the stove, chimney liner and installation would never be recouped before they are banned by the green brigade. Not worth the risk IMO.

Qyburn

PeteTheMoneySaver said:

Discussion thoughts 3./

I realise hardwood takes longer than softwood to season. Presumably, hardwood burns for longer than softwood, and therefore in theory provides better economy on a cost/burn time basis. If this true, has anyone had experience with both types of wood and been able to draw any conclusion regarding the comparative number of hardwood /softwood logs burnt over a set period?

In very rough terms properly seasoned wood gives about the same amount of energy per kg whether hardwood or softwood. In detail softwood may give a little more because of resin content. One cu.m of softwood is around 250kg, hardwood 350kg assuming Ash/Birch/Beech/Oak/Sycamore etc rather than Poplar or Willow.

Softwood is cheaper and quicker to produce, so costs less per kWh. It also gets the stove up to temperature quicker.
Hardwood gives more energy from the same volume so the stove doesn't need refuelling so often.

We use a mix, buying in mostly softwood and using our own hardwood (mostly Ash). 

Moneysavingchap

maisie_cat said:

Moneysavingchap said:

Discussion point 4 - the particulate matter given off by wood burners is harmful to your health. I personally wouldn't touch a wood burner with a barge pole. 

The less things being burnt in your home the better. I do have a gas boiler but that is significantly cleaner and I don't sit directly around it of an evening. 

I have a particulate matter monitor in my living room 2 metres from the stove and it never registers outside the green zone. Burning properly seasoned dry wood is the key, as is being aware of how to use a stove properly.
We are lucky that we have access to free wood as a product of having to fell diseased trees, buying wood is expensive.
Having said that, if I had mains gas I would use it, it's cheaper per kWh than wood, we have a wood pellet boiler which is very efficient wood and it costs 12.5p/kWh now, but was15p/kWh a couple of months ago compared to gas at 9p?

I don't disagree that it can be done as safely as possible, but for me I just couldn't sit round a fire not knowing exactly what the wood burner is putting into the air in an enclosed space.

For me it is not worth it, although I agree with what you say above - it is often the best option for those without mains gas as long as you keep on top of your use and maintenance. 

I thought it was worth adding as one of OPs discussion points. 

PeteTheMoneySaver

Thanks so much for all your answers so far. Keep them coming.

I found a very useful web site regarding running costs. I am not currently allowed to post the link directly but google 'homebuilding How Much Does a Log Burning Stove Cost to Run?' to  find it, and then search for the section entitled 'How Much Does a Log Burning Stove Cost to Run?'.

I had to refactor for the current prices of gas and wood, but even after that it still corroborates the evidence provided in this thread regarding relative running costs so far.

I don't think a fresh wood burner install makes sense on a financial footing based on the evidence so far.

I am thinking about moving soon (maybe in the next 5 years or sooner), and if I had a wood burner already installed in a new home, I would consider buying, storing, and seasoning fresh cut logs for however long it takes. The wood burner could then be uses for winter 'treat' evenings, or for power outages, knowing that the comparative cost of the fully self-seasoned logs makes the solution more palatable financially.

Sensible responses welcomed :-)

FreeBear

PeteTheMoneySaver said: Fundamentally, I am trying to assess if I can save enough money to claw back the cost of fitting the wood burner over a number of years, and how many years that might take. I intend to use the wood burner enough to burn through 3 cubic meters of firewood per winter which I can buy for £340.

Discussion thoughts 3./

I realise hardwood takes longer than softwood to season. Presumably, hardwood burns for longer than softwood, and therefore in theory provides better economy on a cost/burn time basis. If this true, has anyone had experience with both types of wood and been able to draw any conclusion regarding the comparative number of hardwood /softwood logs burnt over a set period?

A couple of comments - Hardwood includes stuff like Poplar & Willow.  I'm currently using some of the latter, and it burns very fast. OK to get the fire going, but I wouldn't want to be burning it all winter.

You need to be careful when buying logs. A 2 cubic metre load may look a lot when tipped, but once stacked, the quantity may disappoint. Certainly not enough to last me more than a couple of weeks. I have a 3m by 2m shed stacked with logs (about 7m³) with a good mix of soft and hard woods. That is enough to get me through a winter. On top of that, I try to have the same again, if not more, stacked under cover ready for a second/third winter - This ensures that the bulk of the logs are well seasoned before stacking in the wood shed in spring. Baking in the shed during the summer ensures the logs are perfectly dry. Do not under estimate the amount of wood you'll get through, especially if it is a long cold winter.

I have a 7KW inset stove (Arada i500). A bit overpowered for the room, so a fair bit of heat escapes to the rest of the house to keep it warm. Also have a couple of sensors embedded in the wall above the stove to monitor the temperature - I regularly see temperatures well in excess of 120°C, on occasions hitting 180°C. At that sort of level, one needs to think carefully about materials used to finish the chimney breast and decorations. Gypsum plaster will crack and flake off over 50°C, so either a heat resistant plaster such as Vitcas or a pure lime plaster needs to be used. Forget using wallpaper as it will char, and most paints won't last long either - With a lime plaster, pigments can be mixed in to add colour and save painting. Finding a tradesman with the experience & skill to give a good finish is not going to be cheap.

On the plus side, with the amount of heat going in to the chimney breast, it acts as a very good thermal store. Keeps the lounge nice and warm overnight once the fire has gone out.

One last point. A stove generates a lot of mess. From bringing logs in (including bugs & spiders) to the ash when cleaning the stove out in a morning. Sweeping the flue at least once a year produces black soot that gets everywhere...

Ectophile

Sweeping the flue at least once a year produces black soot that gets everywhere...

You need to find another chimney sweep.  Mine puts a cloth over the stove, and sucks all the soot into a vacuum cleaner.  No mess at all.