Waste materials can be used to significantly improve energy efficiency

A new study by Farres Yasser, a PhD candidate at Nottingham Trent University, has found that waste materials can be used to significantly improve the energy efficiency of homes in hot, arid regions. The research, which took place in Cairo, Egypt, found that a composite of egg trays, cardboard, polypropylene plastic lids and Styrofoam can be used to retrofit single brick homes with exterior wall insulation. More than 70% of homes in Egypt are considered to be poorly insulated, and the study offers a sustainable solution for these homes. In addition to being largely available for free, the composite insulation can be easily compressed in an environmentally friendly manner with the help of local tradespeople and residents. The insulation was made by filling egg trays with papier-mâché and adding discarded plastic lunch box lids and Styrofoam on either side, which were then glued together with sand and adhesive and compressed with gravity. Tests during the summer found that the insulated structures were on average 3°C cooler than non-insulated structures, and during the winter, the insulated structures were up to 3.6°C warmer between 7am and noon. The energy savings for households using the composite insulation ranged from 2000-3500 Kw h in the hottest months of the year, depending on the cooling device used. Overall, the study demonstrates the potential for commonly discarded materials to be used to transform the way homes are insulated and offers a low-cost, locally available, and environmentally friendly solution for improving energy efficiency.