Energy Changes in a System (AQA GCSE Physics): Revision Notes

The lower the thermal conductivity of a material, the less heat energy is lost. This means that materials with low thermal conductivity are better at keeping heat inside a building, making it more energy-efficient.

Methods to Reduce Heat Loss:

• Walls: Builders insulate walls by packing the cavity (the space between the inner and outer walls) with insulating material, which has low thermal conductivity. This reduces the amount of thermal energy that escapes from the house, keeping it warmer in winter and cooler in summer.
• Windows: Double-glazed windows have two layers of glass with a gap of air or gas in between, which also has low thermal conductivity. This design reduces the amount of heat that can pass through the windows, helping to maintain a comfortable temperature inside the home.

• Roof: Loft insulation involves placing insulating material in the attic or roof space. This insulation prevents heat from escaping through the roof, which is one of the main areas where heat loss can occur in a building.