There are two very important elements to consider when choosing the size of your stove:
1) Physical Size - Do you have enough room for the stove to function properly and conform to building regulations.
2) Output - Do you have the right amount of heat for your room.
Height
The distance from the top to bottom of the stove. Most stoves are quite short, but care should be taken if you purchase a canopy as these sit on top of the stove adding height. You should ensure the top (and sides) of the stove are a safe distance from any combustible material such as wooden lintels or beams. It is recommended that you allow around 22", however it is wise to check with the manufacturer of the stove you are interested in as the distanced advised may vary. The height listed does not include the flue collar if the top flue outlet is used.
Width
The distance across the front of the stove as you look at it face on. Ensure the stove will fit in the narrowest width of your fireplace if you are using one. If you are placing your stove into an inglenook, it is recommended that you have at least 150mm (6") space either side of the appliance, although this may be reduced slightly for smaller output stoves. This is not a regulation, but ensures that the heat from the sides of the stove enters the room, protecting against heat build up which may damage the stove. Also there are often workings on the side of the stove which need to be accessed.
Depth
The distance from the front to the back of the stove. The depth of the stove is important as you need to make sure you will have the regulation 300mm (12") of the hearth in front of the front legs of the stove once installed. You should also allow a 50mm (2") gap at the back of the stove. If you choose to use a rear flue outlet on a stove, connected to either a 90 degree bend, 90 degree tee or manufacturers fitting, this will add extra depth onto the stove, usually around 160mm depending on flue size.
Output
The heat output of a stove is measured in Kilowatts (kW). The output you require is dependent on the size of the room to be heated. To identify the output you require either use our calculator below or the simple calculation which follows.
Simple Calculation: Multiply Room Length x Room Width x Room Height (measured in metres). Divide the figure you have (the space of your room in cubic metres) by 14. Your final figure is the output you will need from a stove to heat your room.
This is not an exact classification, but can be used as a good 'rule of thumb'. The ability of a stove to heat your room will be affected by such aspects as a larger than usual number of doors or windows (including patio) in the room, or other draft sources. In these cases you may need to look at a stove with a greater output.
For those people looking to buy a stove for aesthetic reasons, heat output may be irrelevant, however it is important that you do not buy a stove with an output too large for your room. Doing so may cause you to have to run the stove at a lower output, resulting in poorer efficiency, possible flue problems including consendation and reduced visual appeal due to smaller flames and under performing airwash.