To produce a comfortable room temperature of around 21º/22º Celsius (70º Fahrenheit), when the outside temperature is 0º, you will need about 1kW of heat for every 14 cubic metres of space. 1kW is the equivalent of approximately 1 bar of an electric fire.
The following formula and example will give you a reasonable guide to the heat output you are likely to need. To establish the cubic capacity of the room, measure the length by the width by the height, for example a room that is in the region of 6.5 metres. (21ft. 6") x 4.5 metres. (15ft.) x 2.4 metres high (8ft.) will require a stove of about 5kW output to adequately heat its 70.2 cubic metres.
A stove with a higher output can be used if it is to be run with a lower fuel level. With a little experimenting you will quickly find the fuel loading that is right for your comfort. A small increase in the heat output may be required depending on the number of windows and doors and the level of insulation there is in the room.
Now you have calculated the stove output you need, go to our new Stoves4u.co.uk web site to see the whole range of stoves we offer