The Cosy Post.
UK home insulation, with the real numbers.

Independent · Source-cited · Non-commercial

Home insulation,
with the real numbers.

Working out whether to insulate your walls or loft shouldn't take three weekends and an installer's optimistic forecast. We publish plain-English breakdowns of the costs, payback and grants. Every claim is cited to gov.uk, the Energy Saving Trust, or another primary source.

Start with cavity walls →
Row of UK terraced houses with brick facades under overcast sky

Sources we work from

  • gov.uk
  • Energy Saving Trust
  • Ofgem
  • Office for National Statistics
  • BRE

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Featured guide

Cornerstone · Cavity walls · 8 min read · with eligibility tool

Is cavity wall insulation worth it?

An honest 2026 cost / benefit answer. Install cost by house type, grants available, savings vs gas and electricity bills, and when cavity wall insulation makes sense (and when it doesn't). Includes a 5-question eligibility check for your house.

Read the guide →
Worker drilling into brick cavity wall during insulation install