www.woodstovewarehouse.co.uk

WOODSTOVES

Long before ‘houses’ came to be built, the ‘Hall’ was the main type of dwelling for all but the lowest levels of society in this part of Europe. Constructed mainly of wood, the hall was simply one large room open right up to the pitched roof, with a hearth in the middle for warmth and cooking. Chambers or ‘bowers’ were added according to the wealth of the owner, and this style of living was commonplace by the late fourteenth century, at least according to Chuacer;-

A poore widwe, somdel stape in age,

Was whylom dwelling in a narwe cottage,

Bisyde a grove, stonding in a dale….

Full sooty was hir bower, and eek hir halle,

In which she eet ful many a sclendre meel.

Dormer Cottage at Petham ( just south of Canterbury) probably dates from the 13^th Century and would fill this description well, whilst chimneys and ceiling have been added, one can see from the framing how the end rooms or bowers, were open to the roof and would fill with smoke and soot from the only heat source, the open fire in the middle of the hall.

It is difficult to date the first chimney stack or where this innovative idea came from, but it started to appear during the Tudor period. Apart from reducing the smoke and dirt in the ‘Hall’ the increased safety of confining the sparks to a brick or stone chimney must be the reason why over 3,000 hall houses survive in Kent alone.

There are added advantages of placing stacks centrally to the building:-

They can act as supports for ceiling joists.

They can serve more than one room.

The massive warm stack serves as a ‘Storage heater’ for the whole building when the fire is not alight.

These facts are often overlooked by today’s architects with most new houses having chimneys on gable ends.

These early simple fire places were large brick or stone openings, with timber or stone lintels, which could be plain, chamfered, moulded or carved. Hearths were of stone or brick which had to be regularly re-laid as did the fire back if it was not protected by a cast or wrought iron fireback.

The UK has always been blessed with a good energy supply, and coal gradually replaced wood as the main source of heat in British towns from the end of the 16^th Century onwards. Wood is best burnt on a flat bed but it was soon realised that to burn coal efficiently, a smaller grate than that for wood was required, and it must be raised to cool the grate and allow for the collection & removal of ashes.

The dogs used to hold the logs up were at first replaced with ‘coal baskets’, often these are unnecessarily used for logs today. Later with the advent of cheaper cast iron the ‘cast iron insert grate’ became the norm.

WOOD BURNING, SOLID & MULTIFUEL STOVES.

In Europe there was less coal and greater distances and it is here that the wood burning stove has its origins. The British were introduced to the ideas in the 17^th Cent. where they saw them in the Dutch & German communities in the ‘New World’ where coal had not yet been discovered.

In much of England, coal remained cheap, with female and child labour used in the mines. The British continue to wastefully burn coal in open fires, with the exception of their kitchen ranges, to the present day.

Why wastefully?

With an open fire, the air has to travel towards the fire and up the chimney, otherwise the room would fill with smoke. But this means they are notoriously inefficient, as they give off no hot air, only radiated heat. Your face feels hot but the back of your neck is cold. The maximum efficiency of an open fire with the best design is about 25%, but a large opening (greater than 18 inches) reduces this to 20% or less, whilst an inglenook can be as low as 5% or with central heating actually negative heat. Things improved vastly with the concept of the convector box, used extensively in Europe. It only caught on in the UK after the second world war. Here a double skin fire box is used so that convected hot air can be taken off the back of the fire thus doubling the heat output for the same amount of fuel, & halving the fuel bill. But there is still little control of the air flow which drags the heat out of the room as it roars up the chimney. A stove on the other hand, only allows the air that is required for combustion to be wasted up the chimney. Air is conducted around the stove and warms as it passes, as well as the radiated heat leaving via the glass door. Efficiency ratings are usually well over 80%, quartering the fuel bill.

Before you view the large range of stoves available, let us try to explain some of the differences in the designs of the appliances and what they mean to you the end user.

In short, wood burns best from the top downwards on a thick bed of ash. When burnt in this manner nearly all the fuel is used and all that is left is a very fine white ash, and there is very little of that.

‘Coal’, usually referred to as solid fuel because of the wide variations, on the other hand, burns more fiercely and produces more ash so it is best burnt on a grate so that the bars can be kept cool by the rising air. This also allows the ash to fall through, not clogging the fire and restricting the supply of oxygen. As wood can burn on a grate, what most manufacturers call multi-fuel, is in fact just a solid fuel grate with or without riddling facility. One of the few exceptions to this is probably the ‘Charnwood’ range of multi-fuel stoves. With these, a clever grate system can be turned from either a flat bed, or in the second position, an open bar grate. Moving between the two acts as a riddling system, so in effect they can be either wood or solid fuel burners. Nobody yet makes a stove that can burn solid fuel and/or gas or oil, these have dedicated gas or oil burners in them so they have neither a bed nor a grate.

In recent years, efforts have been made to reduce the emissions of all boilers and stoves. By allowing the combustion air to be preheated and to enter from the top it was found to give a more complete combustion. As a spin off it was also found, that, if arranged to be forced down in front of the door, an air curtain kept the glass remarkably clean. This is now known as the 'air wash system'. With 'cleaner staying' glass it has allowed the designers the opportunity to increase the glass area in the door design thus allowing the view of the fire and the infra red radiation to be uninterrupted. Stove designs that incorporate two small glass doors, to be opened to view the fire, ( which loses control of the burning rate and lets all the heat up the chimney) are now few. Nothing in life is 100%, but air wash certainly does work well on most stoves to which it is fitted, and even if smoking up does occur because damp green wood has been left smoldering near the glass, a good blast with fresh wood burning usually clears it off.

There are three stages in the combustion of wood. The first stage is when the water boils off. Yes, there is a lot of water even in dry, seasoned wood. A small log will contain over 1/2 pint even when it registers only 20% moisture content with a meter. During the second stage, the resins in the wood are boiled to form hydrocarbon gases, these form the yellow licking flames when burnt (just like a gas effect fire!). It requires a hot secondary air supply preferably 300-500 deg.C. (as in air wash or properly designed wood burning stoves) to burn these gases, but remember, if you do not burn them you waste approximately 1/3 of the energy in the log and you will send the boiling resins up your chimney to condense on the chimney walls. Finally you will be left with the charcoal, clean heat, almost pure carbon, that will combine with oxygen from 150 deg.C. plus to form carbon dioxide and heat. Of course all the three stages are going on simultaneously at any time during the normal running of the stove or fire, but the understanding of the process highlights some of the design and system running methods.

Burn only dry wood. If you are serious about burning wood you must sort out supplies and the relevant storage problems. The wood must be bought, sawn and stored under cover the season before you require it. 

Make sure you have a stove with a hot secondary air supply.

Open the stove up every time you reload to allow the gases to be burnt.

Chimney design: Insulated chimneys are essential for burning wood. Even the best stove, run properly with the best dry wood will let boiling resins up the chimney. These condense at approx. 150 deg.C., if the chimney is well insulated they will not condense out, but a standard chimney will gradually get saturated in foul smelling tar, which is also a fire hazard. It will first be noticed in the loft area but gradually get lower until tar stains appear in the upstairs chimney breasts. See notes under PRODUCTS- CHIMNEYS for lining materials and methods.

In this age of cost consciousness & environmental awareness some stoves came with various optional secondary combustion systems. These were delicate though and the idea has been dropped as better combustion with primary secondary and tertiary air had been developed.

Although coal, gas, and electricity have been gradually replacing wood as the main source of heat in the homes of Britain over the last 300 years, it is still an important source of energy. It has another advantage though, when did you last sit round and enjoy the smell, flames and ambience of your gas boiler? But is it green? Well it is certainly greener than the other three could ever be (with the exception of hydroelectricity and electricity produced by other renewable sources, which is less than 5% of all electricity production). It is renewable, trees are always being planted. Then there is dead and fallen wood, not all trunks are suitable for sawn timber. There are vast acreages of coppice in Europe that were used to provide poles, fences and other farm essentials. If not regularly sawn own these will wither and die destroying whole eco systems. The amount of CO2 produced by burning wood almost exactly equals that used by the tree growing. If left to rot on the ground wood produces methane, a gas 20 times more damaging to the atmosphere than CO2. When burnt properly, wood produces virtually no smoke and no acid, so let us turn down the central heating and leave our children and grandchildren some oil, gas and coal, burn wood in a nice stove with a glowing conscience and glowing cheeks from the all round warmth of real flames.

I am importing my own wood boiler stove from the Alsace region. Called the Strasburg, it has a large combustion chamber (18" by 16" deep), primary, secondary and tertiary air flows, and a stainless steel tube boiler above the combustion chamber where the top baffle normally is.

The figures used in this section are taken with kind permission of the Forestry Commission from their leaflet entitled ‘Wood as a Fuel’. 

A solid cubic meter of fresh felled timber weighs about 1 tonne, or 1000 KG, contains up to 600 kg. of water. Selling or purchasing by weight is therefore a bit of a misnomer as the weight will fall by up to 225kg with air drying alone.

Merchants should sell logs or lengths by solid measure. A lorry with a capacity of 1.8Mtr.Cu. holds about 1 solid cubic meter (Cu.Mtr.) of wood.. A wire net cage 2m x 1m x 0.9m high will hold 1 solid Cu.Mtr. of wood. Cleanly trimmed straight conifers occupy about 15% less space.

1.8 Cu.Mtr. of broad leafed (beech) cut logs (1mtr solid wood) air dried to about 20% moisture contains approx. 1764 kWh. of energy which if burned in a stove at 70% efficiency will give up to the house 1,235kWhrs. or a one bar electric fire on for 1,235 hours (seven weeks non stop).

To calculate the cost per kWh. of a load of wood take;-

Length x width x height of the truck in Meters & multiply this figure by 980 and you have the approx. number of kWh of the load. Divide your load cost by this figure to get the cost per kWh. This can then be compared with your electricity or gas bill. For oil, take your price per liter cost (do not forget to include the VAT) and multiply it by 0.154 to get the cost per kWh. Also remember that oil and gas central heating boilers are only about 65% efficient overall so you should divide this answer by 0.65 to get a good comparison.

In English, 1 lb. of good dry hard wood produces 1kWh/3,340 Btu’s. approx.

It seem to me ridiculous to copy all the manufactures brochures on to my web page. Far better that you look at there own pages which will have nearly all the information you require. When you have chosen one or two models you can phone or visit the showroom to see the stove or get a price. By each hyperlink I have put my personnel comment about the manufactures and there stoves. These are my opinions, but remember you are going to look at the stove for many evenings so aesthetics must be your primary consideration. 

http://www.charnwood.com  Top of the range mixture of steel and cast stoves, well made and solid. Some interesting design, single lever air control. An example of British quality that is exported round the world

http://ouzledale.co.uk A mix of cast iron and steel stoves from one of the oldest stove companies in the UK. The 200 series burns well and is good value for money. The 200 series is an excellent stylish small stove that has room to burn wood.

http://firebellystoves.com Superb contemporary designed British stoves with very large clear vision door. Probably the largest window on the market and the design fits old and new fireplaces. Have a look!

http://www.townandcountryfires.co.uk very good British steel stoves, excellent value, give Clearview and Woodwarm a run for the money. on both quality and efficiency

http://www.euroheat.co.uk  For Nestor Martin & Harmony range of stoves. Top quality cast iron stoves, true multi-fuels, lovely green enamel available on the Harmony range. Satin black is much easier to clean that plain cast black but it is more money. The finish on the hole range is superb. This is a true example of 'you get what you pay for'.

http://www.broseleyfires.com  Solid, different and good value.

http://www.francobelge.com Cast iron stoves. Solid, heavy but no frills and finish is not up to Euroheat hence the price difference.

http://www.flamewavefires.co.uk Excellent value cast iron stoves from the other side of the world. (New Zealand)

http://www.aarrowfires.com    Budget stoves that work well.

http://www.dunsleyheat.co.uk    Solid and dependable, British stoves.

http://www.morsostoves.co.uk    Danish designs, clean and simple, but a little pricey? 

http://www.vermontstoves.co.uk   American stove with fine lattice cast doors, a stile that is popular over there.

http://aga-rayburn.co.uk   A very distinctive solid style. More for coal burning?

http://clearviewstoves.com    Clever name for a quality steel stoves, very pricey? Compare 'Town & Country'.

http://continentalfires.co.uk A wide range of interesting style, very good range of built ins/hole in the walls 

http://dovre.co.uk     Solid style, 2000 series excellent for ingle nooks.

http://hunterstoves.co.uk  Steel stoves at half the price of some makes, big range.

http://jotuluk.com    Norwegian, quality, pricey, distinctive and good.

http://www.metaldev.demon.co.uk Woodwarm stoves, good but pricey. Compare 'Town and Country'.

http://www.villager.co.uk    Steel stoves with cast doors. The double door range does not have very good air wash and is primarily designed to be used with the door open. Excellent value for money.