In The existing SEDBUK score construction a typical Efficiency boiler could be considered G-rated and is likely for being 30% much less efficient* than a new Worcester A-rated boiler. Translated by Mouseover text to see first. Simply click the button underneath to return on the English Edition of the site. http://tips-water-heater53849.pages10.com/5-Easy-Facts-About-types-of-heating-systems-Described-23673205