Ways to reduce energy transfers at home and what is a U- value? Cavity wall insulation: this reduces enegy loss thorught the outer walls of the house. The space between the two layers of brick is filled with plastic foam. Plastic foam and the air bubbles inside it make it a good insulator. It traps air in small pockets, reducing convection currents.
Loft insulation: We use fibre glass to reduces the rate of energy transfer throught the roof. Fibreglass is a good insulator, the air between the fibres help reduce conduction.
Alumium Foil: We use this behind the the radiator panel, between the wall and radiator. It is stuck on the wall so it reflects the radiation away from the wall.
Double glazed windows: Are two glass pieces with either dry air or a vacuum between the panes. Dry air is a good insulator so it reduces the rate of energy transfer by conduction because conduction only takes place in solids, the air between doesn't let it happen. A vacuum reduces energy transfer by convection, because convection currents need medium particles ( fluids= Liquids or gases) to take place.
U-values: U- values= the enrgy per second that passes thorugh one sqaure metre of material when the temeprature decrease is 1 degrees centigrade. We use U-vaalues to compare how good materials are as insulators, the lower the U-value the better the material is at insulating.