What is the physics behind loft insulation?

Answer 1

Insulation impedes the flow of energy. In the case of insulating a loft, this energy is in the form of heat. In the winter, when the inside of the house is warm and outside is cold, the insulation makes it more difficult for heat to escape through the roof. In the summer, the insulation keeps the heat outside the house. The rate of that increased difficulty is called an R-factor, such as R-30 or R-60. The higher the R-factor, the better insulated a house will be. Up to 25% of heat loss in a house occurs through the roof, so in theory, a well insulated loft could reduce heating and cooling bills by 20-25%.

Answer 2

Loft insulation works by reducing heat transfer through conduction, convection, and radiation. It creates a barrier that minimizes the amount of heat that escapes through the roof, keeping the living space below warmer and reducing the need for heating. The materials used in loft insulation have high thermal resistance, which slows down the movement of heat.