Keeping Homes Warm Flashcards
What types of surfaces reflect infrared and what types absorb infrared?
Shiny surfaces reflect
Dark or rough surfaces absorb
Explain how a convection current works
Gas/liquid becomes hotter after being heated and is therefore less dense so it rises. As it cools again it becomes more dense and sinks back down.
What is payback time?
How long it takes to pay for the insulation from the savings you make
When describing heat loss from a house, what is the source and what is the sink?
The source is the house and the sink is the atmosphere
What types of heat loss does fibre glass loft insulation reduce and how?
Conduction and convection.
Works by trapping layers of air, which is a good insulator, between the fibres.
What type of heat loss does reflective foil on walls behind radiators reduce and how?
Radiation
Works by reflecting infrared heat back into the room instead of allowing it to be absorbed by the wall.
What types of heat loss does cavity wall insulation reduce and how?
Conduction and convection.
By trapping air (a good insulator) in the foam.
What types of heat loss does double glazing reduce and how?
Conduction and convection
By trapping air (good insulator) between panes of glass.
What type of heat loss do draught excluders reduce and how?
Convection
By keeping as much warm air inside as possible
What is energy efficiency?
A measure of how good an appliance is at converting input energy into useful output energy.
