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Cavity wall savings

Savings following cavity wall insulation depend on a number of different factors, such as:

  1. How much insulation is already present
  2. The size of the building
  3. How many external walls there are (i.e. if the property is detached, semi-detached or a flat)
  4. The fuel used to heat (and/or cool) the property

See below for typical savings:

MeasureAnnual saving per yearCostPaybackCO₂ saving per year
Cavity wall insulationUp to £160 (England, Scotland and Wales) Up to £230 (Northern Ireland)£450 - £5004 years or fewerAround 650kg (England, Scotland & Wales), 790kg (Northern Ireland)
​Solid wall insulationAround £260 (England, Scotland & Wales) £380 (Northern Ireland)£5,000 - £18,000 (external)
​£3,000 - £14,000 (internal)
​Varies​Around 1,100kg (England, Scotland & Wales), 1,300kg (Northern Ireland)

Figures above are based on a gas heated semi-detached house (three bedrooms). All data obtained from the the Energy Saving Trust (EST).

Remember, these savings are made every single year, so making an investment in insulation now will save both energy and money, year in, year out.