Grant developed the first oil-fired external boiler in 1986 and although the concept was new to the oil market, it
quickly became a popular addition to the range. Today, as around one in four oil boiler installations are external, Grant have expanded the number of options available with the launch of three competitively priced Eco External Modules. The models have outputs between 15 and 35 kW (50-120,000Btu/h) and gross seasonal efficiencies of 92.1 - 93% gross, SEDBUK ‘A’ rated.

The Grant Vortex Pro Range of external modules encompass Grant’s original Vortex heat exchanger and have some of the highest efficiencies available in the market today. The boilers are available in four outputs ranging between 15 and 46kW (50-157,000 Btu/h).