ABSTRACT
For an average family using between 700 and 1200 litres of hot water per week, the energy involved can be a significant proportion of the whole energy budget at around 20 per cent. If a high level of insulation has been achieved the proportion is higher. The most popular heating method is by an electrical immersion heater because of its convenience, safety and low capital cost. At the same time it is the least environmentally acceptable with a high carbon equivalent for every litre of water. Of all the fossil fuels natural gas or methane creates the least carbon emissions. In terms of kilograms of CO 2emitted per gigajoule of delivered energy, gas produces 54 kg and electricity 141.6 kg (Source: Building Research Establishment).
