Insulating Houses

Question 0

How can we prevent loss of heat through walls?

Answer 0

Walls are made up of 2 layers with a cavity full of air between them. Air is a good thermal insulator and a poor thermal conductor but the air can move around and heat can be transferred to the surroundings by convection.
The cavity can be filled with an insulating material which traps pockets of air but prevents heat loss through convection as the air cannot move and form a convective current.

Question 1

Why do we insulate houses?

Answer 1

Energy flows form a hotter region to a colder one. The house acts as a HEAT SOURCE and the surroundings act as a HEAT SINK.
The house cools and the surroundings warm up.
Insulation reduces the loss of heat to the environment through conduction, convection and radiation and saves money.

Question 2

How can we reduce heat loss through the roof?

Answer 2

Heat loss through the roof can be reduced by using thick layers of insulating material such as mineral wool or rock wool which traps air and stops it moving around.

Question 3

How can we reduce the heat loss through windows?

Answer 3

Heat loss through windows can be reduced with double glazing with a vacuum or air trapped between 2 panes of glass.

Question 4

How else can energy be saved?

Answer 4

Energy can be saved by reducing the amount of energy we use e.g.
Turn the heating down.

Question 5

What do we mean by payback time?

Answer 5

This the amount of time it takes to recover the amount of money spent preventing heat loss by insulation.
The method with the shortest pay back time is the most cost effective.

Question 6

What are different ways of insulating a house to prevent energy transfer?

Answer 6

Energy transfer can be reduced by limiting heat loss through convection and conduction:
Loft insulation
Cavity wall insulation
Double glazing
Insulation of hot water tank
Solar panel to produce hot water from the energy form the sun.

Question 7

What are some ways of increasing energy transfer in homes?

Answer 7

Radiators have a large surface area to increase the heat radiated to the air in the room.

Boilers have the heating element at the bottom. Hot water rises and creates a convection current so that all the water is heated.