Wood Burning Defra Stoves

This will depend entirely on the size of the room, the location of the stove within the house and how well the house is insulated. There is a guideline calculation to help you find this out: measure the room (length x width x height) and multiply these figures. Divide this figure by 14 and this will give you the nominal heat output. If your room is poorly insulated or without double glazed windows, divide the figure by 10. Similarly, if your house is new-build and the room is very well insulated, divide the figure by 25 to achieve your nominal output. Be aware that many stove manufacturers offer a ‘nominal’ output, and this will have an output range (for example, if you have a 5kW nominal output stove, it will have a range of about 3-7kW, depending on the amount of fuel used and the positioning of the air controls). You will also find that there are often different sized stoves with the same nominal output. This is due to the size of the firebox inside the stove and the amount of fuel used to measure the output. If the same amount of fuel is used to measure the output but in different sized fireboxes, there will inevitably be the same output. Be aware of this when choosing your stove, as having a stove with a large firebox but only loading it with a small amount of fuel will cause problems during the combustion process and will result in the air wash not working properly. Similarly, if you buy a small stove and fill it to the brim with fuel, you will cause problems due to overfiring, which will result in damage to your stove, baffle and/ or flue system as well as the potential risk of a chimney fire. There are also limitations regarding the positioning of the stove, either freestanding in a room or in an opening. These are known as ‘distances to combustibles and non-combustibles’ and will vary with each manufacturer. As a general rule, there should be a minimum of 100-150mm to non-combustible materials, such as brick. This is to ensure good airflow around the stove, allowing heat to radiate out into the room. If this is not achieved, brickwork and plaster around the stove can crack due to excessive heat, and most of the heat will be lost up the chimney. If you are in any doubt and need help choosing the right size stove for your room, come and talk to us at Firebox Stoves and can provide you with friendly, expert advice.

Absolutely! Although if you are planning on having a stove installed in a new-build or passive house, do not follow the guidelines for sizing a stove for use in a regular home. Due to increased insulation and lack of natural draughts, a stove with a significantly lower output would be recommended so as not to produce too much heat. In a new build or passive house, air flow is significantly restricted from the external to the internal and so choosing a stove with a direct air supply option is a must. This will ensure the air used for combustion is taken directly from outside as opposed from in the room where the appliance (and occupants) are located. This will also reduce the risk of carbon monoxide poisoning as the fire burns out as the combustion air is not being recycled in the room. Not every stove is direct air compatible, so it is important to check with your supplier and select the right stove whilst also ensuring the building is able to have the pipe venting directly through an external wall.

A multi-fuel stove can burn wood as well as solid fuels such as coal, however you cannot burn coal on a dedicated wood burning stove. Wood burns best on a bed of ash and burns from the top downwards, because of this, dedicated wood burning stoves do not require (although some have) a grate or firebars which allow for air to reach the fuel from the underside. Instead, woodburning stoves generally tend to have a vermiculite or ceramic base on the base of the firebox, on which to build up a bed of ash to help combustion. Due to more metal parts and more moving parts, generally multifuel stoves cost between 5-15% more than there wood burning equivalents (where a manufacturer offers both options for a model of stove) but the extra cost is usually worth it as it gives the owner the flexibility of choice of different fuels and the practicality of an ashpan for easy cleaning. If you live in a smoke control area choosing a multifuel stove (that can burn approved smokeless fuels) as opposed to a DEFRA approved wood burner means that the range of stoves that you can look at is not reduced.

Defra approval refers to testing carried out by the governmental bodies to monitor and lower emissions, particularly in cities and built up urban areas where pollution levels are high. It can be applied to any appliance that emits smoke and ensures that these appliances do not emit smoke beyond the levels required to adhere to the Clean Air Act 1993. The Clean Air Acts of 1956 and 1968 were introduced to deal with the smog’s of the 1950s and 1960s which were caused by the widespread burning of coal for domestic heating and by industry. Under the Clean Air Act local authorities may declare the whole or part of the district of the authority to be a Smoke Control Area. It is an offence to emit smoke from a chimney of a building, from a furnace or from any fixed boiler if located in a designated Smoke Control Area. It is also an offence to acquire an ‘unauthorised fuel’ for use within a Smoke Control Area unless it is used in an ‘exempt’ appliance. The current maximum level of fine is £1,000 for each offence. If you live in a Smoke Control Area and wish to use a wood or multi-fuel appliance, fear not, as there are many exempt appliances on which you can burn authorised fuels. Authorised fuels are fuels which are authorised by Statutory Instruments (Regulations) made under the Clean Air Act 1993 or Clean Air (Northern Ireland) Order 1981. These include inherently smokeless fuels such as gas, electricity and anthracite together with specified brands of manufactured solid smokeless fuels. These fuels have passed tests to confirm that they are capable of burning in an open fireplace without producing smoke. Exempt appliances are appliances (ovens, wood burners and stoves) which have been exempted by Statutory Instruments (Orders) under the Clean Air Act 1993 or Clean Air (Northern Ireland) Order 1981. These have passed tests to confirm that they are capable of burning an unauthorised or inherently smoky solid fuel without emitting smoke. Check if you are in a Smoke Control Area at the following website: www.uksmokecontrolareas.co.uk