SIA and Eco Design Multifuel 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 multifuel stove is very similar in external appearance to a woodburning stove, however, the internal workings will differ significantly. A multifuel stove is designed to burn wood, coal and smokeless fuels and generally have riddling bars or grates at the bottom to allow airflow in to help the combustion process. Grates can be of the fixed or riddling variety, fixed (as the name suggests) are immovable. Riddling (movable) grates or firebars allow for the fuel to be ‘riddled’ which is the term used for the removal of ash from the combustion chamber, this also serves to ‘stoke’ the fire. Most stoves with a riddling facility allow this to happen without having to open the stove doors. Coal burns best with combustion air fed from both the bottom and the top of the fuel, for this reason coal burning stoves or multi fuel stoves are equipped with grates or firebars. Another feature of a multi fuel stove is an ashpan. The ashpan is the metal pan that sits in the bottom of the stove collecting the ash that falls through the grate, by riddling the stove you cause ash to fall through the firebars/grate into the ashpan. This allows for relatively clean removal of ash from the stove. It is important that you do not allow large amounts of ash to collect in the pan before emptying; ash has pretty good insulating (reflective) properties and doing this can cause extremely high temperatures directly under the grate which can lead to warped, cracked or even completely burnt out fire grates and bars.

SIA Ecodesign Ready is a European-wide programme established by the Stove Industry Alliance (SIA) to ensure all stoves designed and produced after 2022 adhere to strict emission targets and regulations, set by the SIA and HETAS. In simpler terms, it means that all stoves must be designed to be significantly more efficient compared to a 10-year-old stove for example, and manufacturers must be able to prove that their stoves release at least 55% less particulate matter emissions through a more complete burning process. Any stove which has not passed the stringent testing will not be allowed to be sold or installed and will be withdrawn from the market by 2022. SIA Ecodesign has been introduced to help meet the Clean Air Strategy 2019 which aims to combat air pollution by reducing emissions and particulate matter by 46% by 2030. The aim is not only to produce more efficient heating appliances which release significantly less emissions, but also to raise awareness about our current air quality and environment and help to educate and raise awareness regarding our unsustainable usage of fossil fuels in the industry, farming and heating sectors. New technology and the way stoves are designed will allow combustion to be more even within the burning chamber to ensure any particulates are burnt off before going up the chimney.