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Space Heating Calculator

The space heating calculator is really all about quantifying how much heating capacity you need for your application. This is relevant for heaters that heat air, rather than for radiant heaters which heat objects and surfaces. For radiant heating there is a separate calculator tool. 


The space heating calculator tool asks for dimensions of the enclosed space to be heated. Essentially this is about providing the relevant information for the volume of the enclosed space to be calculated because it is to this volume that we apply various heating factors in order to derive the heating power required.

It may be the case that your room is not a simple cubical shape. If this is the case we advise working out the volume long hand and then dividing your volume figure by the average ceiling height. This will give you the floor area and the square root of that number can be put into both the length and width boxes, and then put your average ceiling height in the height box. 

Inside Temperature

The space heating calculator need to be able to calculate the temperature difference between the outside and the desired temperature inside. Typically the desired inside temperature will be about 15-16°C for manual working environments for example in fabrication workshops, whilst 17-19°C is more typical for more more sedentary working environments where staff are typically seated whist they work. More dexterous tasks such as using computers and fine hand work may demand 19-20°C. 

Outside Temperature

The 'ambient temperature outside the building' is perhaps misleading. What the calculator needs here is the lowest likely temperature on the other side of the wall. This may be outside the building in which case we would typically use -5°C in England, Wales and Ireland, or -10° for Scotland. But it could be that the other side of the wall is other rooms in the same building which may typically be no lower than, say, 10°C. If half the wall is external and the remainder internal then you may judge that 0°C is a more balanced figure.  

Why are these results important?

Different rooms and buildings require different amounts of heating power to ensure that they can achieve a consistent, optimal temperature. Knowing how much heating you require will help to guide your choice of heating equipment. The other benefit of the space heating calculator is that it can provide heat requirements based on different characterisations of building. This means that it can often show that it is well worth adding insulation to a building to lift it from say 'moderatly insulated' to 'well insulated' and then selecting heaters based on a smaller requirement.