Calculating Stove Size

When calculating the best stove in relation to heat output it is important to take into account the room size. This is not an exact science, but as a general rule we use the following calculation:-

L X B X H divided by 10 (for poor insulation) = heating requirement

L X B X H divided by 15 (for average insulation) = heating requirement

L X B X H divided by 10 (for good insulation) = heating requirement.

For example 5M x 4.5M x 2.9M = 4.35kW

Then as an addition guide we give some consideration to how you live in the room. If you tend to leave a single door open then we add 1.5 kW to this,  and if its a double doors we add 3 kW.

When operating a stove the clean burn operation occurs when the stove is not slumber burning (Air supply to stove is on low setting). The most attractive flame pattern will occur when the stove is operating at between 70 % and 85 % of its maximum heat output.

This results in the following outputs

Maximum 30% 40% 50% 60% 70% 80% 90%
kW output
4 1.2 1.6 2 2.4 2.8 3.2 3.6
5 1.5 2 2.5 3 3.5 4 4.5
6 1.8 2.4 3 3.6 4.2 4.8 5.4
7 2.1 2.8 3.5 4.2 4.9 5.6 6.3
8 2.4 3.2 4 4.8 5.6 6.4 7.2
10 3 4 5 6 7 8 9
12 3.6 4.8 6 7.2 8.4 9.6 10.8
14 4.2 5.6 7 8.4 9.8 11.2 12.6
16 4.8 6.4 8 9.6 11.2 12.8 14.4

When you have a nominal output of over 5kW, under building regulations you will need a vent to the room. Alternatively you can have an external air kit for the stove.