Table 2

Energy efficiency interventions modelled

Experiment energy efficiency retrofitsVentilation scenarios
RegulationInstaller discretionNo added ventilation
Number of retrofits installed (1000s)
Loft insulation532053205320
Cavity wall insulation656065606560
Solid wall insulation570057005700
Double glazing installation243024302430
Condensing boiler installation10 73010 73010 730
Gas central heating installation310310310
Draught proofing387038703870
Trickle vent and extract fans15 2809000
Extract fan installation only3503500
Extract fan refurbishment505050
Trickle vent installation only2702700
  • Note that trickle and extract fans include all new installations, extract fan only already have trickle vents, trickle only already have extract fans.