An air conditioning system with a COP of 2.2 operates during the daytime (6 am - 6 pm) to remove heat from a building (cold source) at the rate of 1.1 kW (QL). The system is designed such that 70% of the heat rejected through the condenser (QH) is effectively used to boost an existing fossil-fuel-based hot water system (70% of the total waste heat is absorbed by the cold water to be heated up). This hot water system is supposed to warm up 1000 kg/day (mainly used during the daytime) of water from an average of 15 °C to 55 °C. Calculate the percentage of saving in the fossil fuel consumption when the waste stream from the air conditioning system is utilised to boost the hot water system.