How to calculate the heating requirements

Before choosing your heater, you need to determine the minimum power required for your application.

Basic formula

V x ΔT x K = kcal/h

V – Volume of area to be heated (Width x length x height) in m3.

ΔT – Difference between the external temperature and the desired internal temperature (in°C).

K – Dispersion coeffi cient.


V = Width 4 mt, Length 12 mt, Height 3 mt, Volume of area to be heated = 144 m³

ΔT = External temperature -5°C Internal temperature required +18°C, temperature T = 23ºC

K = This factor is determined by the type of construction and insulation

a simple building in wood or in corrugated metal - non insulated.

Simple construction, single brick layer, simple windows, simple roof - Poorly insulated.

Standard construction, double brick layer, few windows, standard closed roof - Moderately insulated.

advanced construction, double insulated brick, few double pain windows, thick pavement foundation,
well insulated roofing materials - Well insulated.

Example: thermal power required

144 x 23 x 4 = 13 248 kcal/h

(V x ΔT x K = kcal/h)

1 kW/h = 860 kcal/h

1 kcal/h = 3,97 Btu/h

1 kW/h = 3412 Btu/h

1 Btu/h = 0,252 kcal/h

Now you can choose the heater which best suits your application.