18 July 2026

What does cavity-wall insulation cost in 2026?

All guide prices in one place: per home, per measure and for projects — plus the factors that decide where you land in the band.

Having your cavity walls insulated in 2026 costs on average € 1,500 to € 3,000 for an average home, including labour and materials. The facade surface drives most of the price: a terraced house has two facades to insulate, a detached home four — and thus sits at the top of the band.

The other shell measures have their own bands. Floor insulation costs € 1,200 to € 2,800; the height and accessibility of the crawl space decide where you land. Ground insulation is the cheapest measure at € 800 to € 1,800 and also works in low crawl spaces where floor insulation will not fit. Unsure where to start? An insulation survey with thermal scan costs € 95 to € 250 and many companies offset it against a follow-up job.

Besides the surface, three things move the price: the state of the cavity (a narrow, fouled or partly filled cavity needs preparation or a different material), the chosen material (EPS beads, glass-wool flakes or PUR foam each have their own rate) and the accessibility of the facade. Randstad rates additionally run 10-20% higher. For HOAs and commercial buildings, project work applies with its own band of roughly € 8 to € 20 per m².

Good to know: a national insulation subsidy (ISDE) exists; the conditions change regularly, so ask the installer about the current scheme. And request multiple quotes — set them against the price index and check that the borescope inspection, the material choice and the nature check of the cavity are named before you agree.