2.3 Heating And Insulating Buildings

Question 1

How can houses be heated?

Answer 1

Electric or gas heaters, oil or gas central heating systems, solid fuel in stoves or fireplaces

Question 2

What are five measures that can be taken to reduce the rate of energy transfer from a home?

Answer 2

• Loft insulation such as fibreglass
• Cavity wall insulation
• Aluminium foil between radiator panel and wall
• Double glazed windows
• External walls have thicker bricks with lower thermal conductivity

Question 3

How does fibreglass loft insulation help?

Answer 3

• fibreglass is a good insulator
• the air between fibres helps to reduce the rate of energy transfer by conduction
• fibreglass reduces the rate of energy transfer through the roof

Question 4

cavity wall insulation

Answer 4

reduces rate of energy transfer through outer walls f house
- insulation is pumped into cavity
- traps air in small pockets
-reduces rate of energy transfer by conduction

Question 5

How does aluminium foil between radiator panel and wall help

Answer 5

Reflects radiation away from the wall so reduces the rate of energy transfer by radiation

Question 6

How do double glazed windows help

Answer 6

• They have two glass panes with dry air
• the thicker the glass and the lower its thermal conductivity, the slower the energy transfer by conduction will be
• dry air is a good insulator
• vacuum prevents energy transfer by convection