1 kW of heating output will approximately heat
25m3 good insulated area
15m3 average insulated area
10m3 poor insulated area

The heating capacity is with an estimated outside temperature of -1°C. For accurate assessment of heating requirements a full heat loss calculation must be completed before installation of any appliance.

Measure the width length and height of your room.
Calculate the three measurements together.
I.E width 4 meters x length 7 meters x height 2.4 meters = 67.2 m3

Advice for unusual shaped rooms.
If the room is shaped in an L configeration calculate the sections as two separate rooms then add together.
If the room has a pitched ceiling calculate the height of the room as half the height of the pitch for a guide. For a more accurate calculation we offer additional assistance. Click here

This is probably the most difficult assessment to make without a full heat loss calculation.
Essentials to keep in mind.
Number of outside walls:- The outside walls the greater the heat loss.
Number of windows. (Single glazed, double glazed).
Type of floor:- Suspended, solid, vented.
Insulation:- Cavity wall insulation, roof insulation.
Age of property:- Modern houses are far better insulated than traditional older Property.
Number of doors:- Are there doors to other rooms or to the outside.
Any other forms of heat:- Existing radiators, stoves or range style cookers in joining rooms.
House location:- Exposed or windy site, north side rather than southern aspect.

Completion of example
The room size in this example was 67.3 m3. In this example the room is of average insulation.
By dividing the room volume by 15m3 (average insulation) the kW demand is 4.48kW.