Cavity wall insulation cost in Ireland

Cost by house type, before and after the grant

These are SEAI's own median installed costs for cavity wall insulation, from grant-funded jobs in the first half of 2025. They include materials, labour and VAT. We take them as published by saveonheat.ie and take away the grant SEAI pays now (checked 28 October 2026).

Costs: SEAI median installed costs, H1 2025, incl. VAT, as published by saveonheat.ie (updated 13 October 2026). Grants: Source: seai.ie wall insulation page, checked 28 October 2026. The cost after the grant is the median cost less the standard grant. Your own quote can be higher or lower.

Cost per square metre

• €7.50 to €13 per m² for pumped bonded bead, including materials, labour and VAT. That puts a typical three-bed semi at about €1,500 to €2,200 before the grant. Source: ShamFix cost guide, 31 July 2026.
• €15 to €30 per m², or about €1,500 to €5,000 for an average semi-D, from a Dublin insulation company's own service page. VAT is not stated. Treat it as the top of the range. Source: Osber, page updated 31 August 2026.

Square metre prices are hard to compare, because each firm measures the wall a little differently. Compare the whole-job price for your house, with VAT.

What moves the price

• Wall area. A detached house has more outside wall than a mid-terrace, so it needs more bead and more drilling.
• Cavity width. A wider cavity takes more insulation to fill.
• Access. A side passage, a conservatory against the wall or a high gable means more time and sometimes a scaffold or a lift.
• Existing insulation. A part-filled cavity is checked with a camera before the installer says if it can be topped up.
• Remedial work. Cracked render, failed pointing or blocked vents may need fixing first. That is extra.

What the quote should include

• A survey of every wall, with the cavity checked through a small drilled hole
• The insulation, the drilling and the filling of the holes to match the wall
• Vents and flues checked and sleeved where needed
• VAT, stated on the quote
• The paperwork SEAI needs for the grant, if you're claiming it

VAT on cavity wall insulation

SEAI's median figures and the per m² prices from ShamFix include VAT. The Osber page does not say. Ask for a written price that states the VAT, so you compare like with like.

What it saves

For most homes with an empty cavity, the numbers are short. After the grant, a semi-D is typically about €200. saveonheat.ie, working from SEAI data, puts the yearly heating saving for a semi-D at €200 to €400, depending on your heating system and how warm you keep the house. That is their estimate, not a promise.

Not every wall can be filled. Read is my house suitable? before you budget.

Where these figures come from

• Median installed costs are SEAI's figures for H1 2025, as published by saveonheat.ie (page updated 13 October 2026). They include VAT.
• Grant amounts are from SEAI's wall insulation page, checked 28 October 2026. Older SEAI PDFs still show lower, pre-2026 amounts.
• The cost after the grant is the median cost less the standard grant. Nothing else is estimated.
• Per m² prices are from two Irish companies' own pages, dated, with their VAT status.

Questions people ask