4.8 explain how insulation is used to reduce energy transfers from buildings and the human body.

4.8 explain how insulation is used to reduce energy transfers from buildings and the human body.

Energy-efficient houses reduce energy transfer by using two layered walls and double glazing windows. The wall is made wide layers of different materials. The outer layer is made with bricks; these have quite good insulating and weathering properties. The inner layer is built with thermal bricks with very good insulation properties. The two layers are separated by an excellent thermal insulator in form of cavity or gap. Reflective aluminium foil is used to reduce heat by radiation.

Windows are made of thin glasses. Two layers are used to trap air, and the thickness is given in such a way to reduce both conduction and convection.

We reduce heat loss in human body by wearing woolen cloths and jackets. This trap the hot air and prevents cold air from entering the body.