Moving Off Grid - Heating 1

Moving off grid can be taxing and one sure fire way of reducing your reliance on the system is to install some form of alternative heating system to heat your property and there is plenty of choice, but watch the commerce element as many companies are jumping on the bandwagon with heating systems and as many people have no real knowledge of heating systems; they can fleece you to maximise their profits. Please read the first section before reading this section which can be found at.

https://goodf.forumotion.com/t15-moving-off-grid

Log burners and wood fired heating systems are becoming big business and it is a general lack of knowledge among so called professionals which is clouding the waters with alternative heating systems in general and specifically with wood burning systems specifically, so what do we need to know.

Wood burning systems come in two basic types which are wood burning stoves/fires and multi-fuel burners which burn wood and coal/coke and they are usually rated in Kilowatts output and here is our first problem as wood burners quote their maximum heat output burning solely wood as this is all they burn; multi-fuel stoves/fires differ as they quote their maximum heat output using the highest heat output fuel which is usually coal and to burn coal you have to buy an additional cast iron grate to burn coal as its additional heat will melt or burn out a steel grate in very little time, then you have to buy the coal or coke. Now we have two issues, first any dealer or seller of log burners is trading up which means they are selling you an accessory and profiting from you by selling additional items at inflated prices to maximise profits; secondly, if you have a multi-fuel stove and you only intend burning logs you have to reduce the quoted maximum heat output by around 1/3rd meaning you are losing about 1/3rd of the quoted maximum heat output stated in a manufacturers literature. Many people fall foul of this rating system and end up with a log burner which is too small for their requirements leaving them with insufficient heat or a stove/fire which eats through fuel.

Next you have to consider the fuel itself, do you have access to free wood? maybe you have a nearby wood and the owner allows you access and take anything which has fallen and if the trees are mature trees you will need a chainsaw to cut them up and transport to get large quantities of fallen timber home, maybe you work for a company which has lots of wooden pallest they don't want and you can take them for free and cut them up at home, maybe you have a timber company nearby who will give you offcuts for free, or maybe you have a contact working as a site joiner who can get a lot of offcuts for free.

Storage is an issue for some people as you need sufficient storage for a years worth of seasoned timber at home and sufficient storage for another years timber to season ready for next year, so you will need sufficient storage for two years worth of timber, have you got the room. Timber needs to be covered after seasoning and this means some form of coal bunker or shed for storing this timber, and a storage area with a roof and lots of airflow to store next years timber to let sufficient air through to season it.
Logs need to be cut and split to allow them to season, basically this is cutting them to length at home and splitting them to the desired size with an axe or log splitter, so why do we do this? basically a whole log or log "in the round" has little surface area to allow the moisture to escape as in reality you only have the ends for the moisture to escape from, by cutting them to length and splitting them you expose more surface area of the logs which allows them to season much quicker than logs left in the round.
If you buy logs in then these may work out more expensive than a traditional gas fired heating system as the cost is rising in demand with the supply and traditional log suppliers will not quote a weight now and they supply by the bag, here is another issue, many supply logs in the traditional one tonne builders bags and often they are not filled to the top, in addition you are paying for a bag and any additional costs such as delivery; and often it is pot luck whether you get good quality logs or a bag of trimmings which are the small unsplit logs which often means they may not be seasoned, so buyer beware.

Many other sources of timber are available, if you have hedges you can save the trimmings and put them through a garden shredder and bag them up as these make a good supplement to your logs, if you have high winds and a neighbours tree becomes damaged you can go and trim the damage, or the whole tree for more free fuel, you can often find council contractors trimming trees by the roadside and they will give you a lot of timber for free as it saves them work and fuel in their chippers, or you can become friendly with a wood owner and trim his/her trees on condition you keep the timber, use your ingenuity. With any wood cutting you will get chips or sawdust and these can be made into logs with the addition of pulped waste paper, to make pulp you tear up old newspaper or shred any other paper and put them into a barrel with water to break down and simply add the same volume of sawdust, mix and compress into a mould and dry.

If you dont feel competent to install a wood burning stove then only get a qualified installer, make sure they are accredited and have sufficient insurance to cover any issues with an installation; if you install your own then check on the regulations and the the requirements and standards the professionals have to adhere to and follow them for a safe and efficient installation.

How effective are wood burners? in reality you can easily reduce your heating bills by around 50% for an average home using your log burner as a supplementary heating system and they are most effective in autumn and spring where you may not need your heating on all the time as you can light a fire in the evening to take the chill off your home and let it run through the night to have your home warm when you get up in the morning, then let it go out during the day. Light it again at night and keep it running for longer as it drops colder and you will reach a point where it is running 24 hours a day, this will provide most of your heat for most of the day and night and as a supplementary system your gas heating wont be constantly kicking in to maintain temperature as it will kick in much less often and for much shorter periods.


Where a log burner is used as the sole source of heat you will need many more seasoned logs and the ability to store a much greater capacity of seasoned and seasoning logs, you will need a log burner with a much higher heat output to raise the temperature of your home to sufficiently high temperatures during the coldest weather and potentially a stove with a back boiler to heat central heating water along with an electric heating pump which now means your heating system is not independent of mains electricity and this is an important consideration unless you have a stand by generator. Temperature range adjustment is an important consideration when using a log burner plumbed into a central heating system as you need sufficient temperature adjustment to allow you to wind the temperature up in the very cold spells and wind it right down to allow the stove to slumber during warmer spells without eating through lots of fuel when it is slumbering.

One other important consideration is environmental legislation in your part of the world, recent advances in log burning technologies mean they have to be more efficient in their combustion of timber and to achieve this they use something called "secondary combustion" which is simply admitting pre-heated air after the main combustion area to burn off any wood gas to reduce environmental admissions, so what is wood gas? when wood is burned it is never totally dry and when you burn it you get the moisture going up your flue/chimney and this contains a gas known as wood gas. By admitting a secondary source of pre heated air this gas ignites and it is burned off which gives you a cleaner and more efficient conbustion and a higher heat output from this secondary combustion, and it is ignited by its own heat.

Hi assassin,
Good article .Regarding wood gas that you mentioned.Before i ditched Sky and pretty much all tv except motor sport .there is a program called Mountain Men where one of the guys runs an old toyota pickup on wood gas with the burner in the back. Whilst its easy to spot that most things on the Discovery channels are staged for the camera ,what are your thoughts on this ? Because if its correct it should be capable of running a decent sized genny .
Its a pity i did not have any of this type of info years ago when i had my own place in the wilds of Cornwall.

Hi Dave

Wood gas has been around for years and it has been superceded by more reliable forms of gas production such as HHO which are easier to produce, cost nothing to produce as you can use wind, solar, or water generation methods for the electricity production along with rain water; and wood gas requires a huge quantity of wood to produce very little gas by comparison. It is only an environmental baddie when it is not used to power a generator or other application and is best burned off for heat production in a secondary combustion to provide additional heat from a log burner and reduce environmental emissions.

For powering a large generator? no, it will power a small one and not for very long as once the wood dries during burning the moisture and wood gas cease to be produced.

I must admit i was very sceptical when i saw it ,that it could power a pick up for anything longer than a few mins.

It can Dave, the limiting factor is the quantities of timber you need and the ability to compress the gas and store it, this makes it uneconomical for most uses.

quite a long series but u can skip through most of it, key is to use the the heat from the furnace as it is making the fuel to make it more efficient, say filling a tank with hot water or central heating as its running.
Its probably best as an emergency backup, the oil can be stored easily.