Fuel Savings

Green roofs have a positive effect in terms of thermal insulation through their ability to cool buildings and insulate them during the winter [dependent on daily conductance of the green roof].

The German Green roofing manufacturer Zinco International has estimated that green roofs can contribute to savings in fuel heating costs of 2 litres of fuel oil/m2/year in Germany and an industrial plant in Frankfurt [Possman Cider Cooling and Storage Facility], which had a green roof installed recovered the cost of the green roof in 2-3 years through the savings in heating and cooling costs, and the reduction in industrial equipment associated with these activities.

A conversation with a building services manager in London happened to uncover that the application of a retrofitted green roof on a building had reduced the need for cooling/heating of industrial plant in the floor beneath. Since the green roof has been installed cooling and heating fans have not been used. It is estimated that about 25.9 MW per year is being saved. Using current electricity rates this is approximately a £4,300 saving per year. If the green roof had been installed as part of the original design of the building and the ability of the green roof to reduce cooling and heating requirements had been known, there would have been a potential saving of £10,000 due to reduction in the need to replace heating and cooling equipment in the floor in question.

A recent article in Heating and Air Conditioning Magazine www.emap.com is availble as a pdf here [500Kb]

A study in Toronto to demonstrate the viability of green roofs. The study focusses on a number of areas particularly air quality, energy and urban heat island.