Section 4 - Reducing Energy Transfers

Question 1

How can you reduce heat transfer in your house?

Answer 1

You can reduce heat transfer in your house by insulating it.

Question 2

Talk through a couple of ways to insulate your house.

Answer 2

Loft insulation: A thick layer of fibreglass wool laid across the loft floor and ceiling reduces heat loss from the house by conduction and convection.

Draught proofing: strips of foam and plastic around doors and windows stop draughts of cold air blowing in, they reduce heat loss due to convection.

Cavity wall insulation: Foam squirted into the gaps between the bricks stops convection current’s being set up in the gap and radiation across the gap. The insulating foam and the air pockets trapped in it also help reduce heat loss by convection.

Hot water tank jacket: lagging such as fibreglass wool reduces conduction and radiation.

Double glazing: two layers of glass with a narrow air gap between reduces conduction and convection.

Thick curtains: Big bits of cloth over the window create an air gap between the room and the window, stopping hot air reaching the glass by convection. They also reduce heat loss by conduction and radiation.

Question 3

How do we as humans reduce heat transfer?

Answer 3

In the cold, the hairs on your skin stand up to trap a thicker layer of insulating air around the body. This limits the amount of heat loss by convection.

Question 4

What do you clothes help us with?

Answer 4

We wear layers of clothes to reduce heat transfer the pockets of air trapped in the clothes and between layers mainly reduce heat transfer by conduction and convection.

Clothes also reduce heat loss by radiation from the body, as the material absorbs some heat radiating out by our bodies.