Black, dull surfaces are the best emitters of heat radiation. Lighter, shinier surfaces are poor radiators of heat.
Radiated heat can also be absorbed by cooler objects. Black is the best absorber. Surfaces coloured silver or white will reflect the radiated heat.
If air is so good why doesn't it work on its own?
Well, the air can convect the heat energy away from the house if it is able to move. If the air is trapped in small spaces between the fibres in the fibreglass it can't move so it doesn't convect the heat energy.
There are two real reasons for reducing heat losses from a home:
- Saving energy means that less energy needs to be produced, so there will be less damage to the environment. (Think about the pollution from a coal-fired power station).
- Saving energy means using less energy so it costs less to heat the house. It can cost hundreds of pounds a year to heat a family house.
End of this topic!
Drafted by Gina (Physics)