Reducing heat loss from your home

Your home loses heat through the walls, windows, doors and roof.

The colder the outside temperature or the stronger the wind, the greater the amount of heat lost.

There are several ways to help reduce heat loss from your home, making it more comfortable and reducing energy bills.

Area	\(\percent\) heat loss	Method	How it works
Roof	25	Insulate loft with mineral wool or fibre glass.	Trapped air between glass or mineral wool fibres reduces heat loss by conduction and convection.
Walls	35	Cavity wall insulation fills the cavity between the outside walls with mineral wool, polystyrene beads or foam.	Trapped air between fibres, beads or within foam reduces heat loss by conduction and convection.
Floor	15	Thick carpets on floors. Mineral wool beneath ground floor floorboards. For concrete floors rigid foam insulation can be used.	Trapped air between carpet threads, wool fibres and within foam reduces heat loss by conduction.
Windows, doors and unused chimneys.	25	Fit double or triple glazing. Heavy curtains on windows. Block up unused chimneys. Draught excluders around doors and windows.	Layers of glass reduce heat loss by conduction. Trapped air between the layers of glass reduces heat loss by conduction and convection. Curtains trap air reducing heat loss by conduction and convection. Draught excluders and blocked chimneys trap air preventing heat loss by conduction and convection.

Area	Roof
\(\percent\) heat loss	25
Method	Insulate loft with mineral wool or fibre glass.
How it works	Trapped air between glass or mineral wool fibres reduces heat loss by conduction and convection.

Area	Walls
\(\percent\) heat loss	35
Method	Cavity wall insulation fills the cavity between the outside walls with mineral wool, polystyrene beads or foam.
How it works	Trapped air between fibres, beads or within foam reduces heat loss by conduction and convection.

Area	Floor
\(\percent\) heat loss	15
Method	Thick carpets on floors. Mineral wool beneath ground floor floorboards. For concrete floors rigid foam insulation can be used.
How it works	Trapped air between carpet threads, wool fibres and within foam reduces heat loss by conduction.

Area	Windows, doors and unused chimneys.
\(\percent\) heat loss	25
Method	Fit double or triple glazing. Heavy curtains on windows. Block up unused chimneys. Draught excluders around doors and windows.
How it works	Layers of glass reduce heat loss by conduction. Trapped air between the layers of glass reduces heat loss by conduction and convection. Curtains trap air reducing heat loss by conduction and convection. Draught excluders and blocked chimneys trap air preventing heat loss by conduction and convection.

Cavity wall insulation

Approximate cost and savings based on an average semi-detached house in Northern Ireland.

Area	Approximate cost in £	Approximate annual energy bill saving in £	Approximate payback time in years
Roof insulation	300	150	2
Cavity wall insulation	475	180	3
Floor insulation	700	45	16
Double glazing	3800	90	42

Area	Roof insulation
Approximate cost in £	300
Approximate annual energy bill saving in £	150
Approximate payback time in years	2

Area	Cavity wall insulation
Approximate cost in £	475
Approximate annual energy bill saving in £	180
Approximate payback time in years	3

Area	Floor insulation
Approximate cost in £	700
Approximate annual energy bill saving in £	45
Approximate payback time in years	16

Area	Double glazing
Approximate cost in £	3800
Approximate annual energy bill saving in £	90
Approximate payback time in years	42

Roof and cavity wall insulation are both relatively cheap and the savings gained mean you get your money back quickly.

Heat transfer - CCEAReducing heat loss from your home