Insulating homes

Loft insulation:

• Fibreglass 'wool' laid across the loft floor
• Reduces conduction throught the ceiling into the roof space

Double glazing:

• Two layers of glass with an air gap between
• Reduces conduction

Cavity wall insulation:

• Two layers of brick with a gap filled with insulating foam
• Reduces conduction and convection

Draught excluders:

• Strips of foam and plastic around doors and windows to stop escaping air
• Reduces convection

Payback time = Cost of installation/Annual saving

Energy transferred(J) = Mass of water (g) x Temp change x 4.2