Electric heating calculator calculates the electric power of the heater required for space heating taking into account the desired temperature difference by the formula: V x T x k = kcal/HR where:

V — volume of the heated room;
T — the difference between the two temperatures inside and outside the premises;
k — coefficient of heat loss (or heat insulation). Ranges from 4.0 (for buildings with very poor insulation) to 0.6 (high thermal insulation).