Are there any recognised formulas to calculate the required power output of a radiator for a room of a specific size that also takes into account variables such as extra height, large areas of glass, insulation of walls etc? Good quality formulas devised by people who know about thermodynamics as opposed to plumber's rules of thumb passed down from the 1950s.
Numerous online radiator power outlet calculators exist but the formula behind them is not disclosed and the results for the same input variables vary from website to website.
