Your walls · your grant
Which wall insulation does my house need?
It depends on how the walls were built. An empty cavity wall gets the cavity grant, the lowest-cost job. A solid or hollow block wall has no cavity, so it needs internal or external insulation. On the BER register 67% of homes have cavity walls and 24% solid or hollow block (SEAI BER register).
How to find out what your walls are, and what each answer means for the grant.
Figures checked against SEAI and Citizens Information on 2 November 2026. wallinsulationgrants.ie is not SEAI or a government body and does not award grants.
- €8,000SEAI's fixed external wall grant for a detached house, the biggest of the three
- €4,500for internal wall insulation (dry lining) on a detached house (SEAI)
- €2,300the higher cavity grant for a detached house, for certain welfare recipients and HAP or RAS landlords (Citizens Information)
- 24%of homes on the BER register with a known wall type have solid or hollow block walls: no cavity to fill (SEAI BER register)
FreeNo obligationOne contractor rings you, not fiveSEAI approves the grant before any work
Grant check
Your wall grant and what's left to pay
Three taps: the wall job, your home, and which rate fits you. The answer is SEAI's fixed grant and its own median cost for the job.
Your SEAI wall insulation grant
€1,300
- SEAI median cost, Jan to Jun 2026
- €1,585
- Left to pay at the median
- €285
SEAI's fixed cavity wall grant for a semi-d or end of terrace at the standard rate is €1,300 (Citizens Information and SEAI, 2 November 2026). SEAI's median cost for that job on a semi-d or end of terrace, January to June 2026, was €1,585. €1,585 less €1,300 leaves about €285. Our sum; your quote can be higher or lower.
Send this for a real priceHow this is worked out
The grant is SEAI's fixed amount for that wall job and home type, as SEAI's wall insulation page and Citizens Information (Citizens Information, updated 22 October 2026) list it. The higher rate applies to cavity walls only. The median cost is SEAI's own figure from grant-funded jobs completed between January and June 2026 (SEAI median costs); the PDF doesn't say whether VAT is in. Left to pay is the median less the grant, our sum. The home must have been built and lived in before 2011, every external wall must be done, the contractor must be on SEAI's register, and SEAI must approve the grant before work starts. It's an estimate, never a quote.
Find out
Three ways to know your walls
- Your BER certificate. The assessor records the wall type; the advisory report lists it.
- A contractor or architect. SEAI's guide says either can tell you, if you don't already know (SEAI wall insulation guide).
- What a cavity wall is. Two rows of brick or concrete block with a gap between them (SEAI wall insulation guide). If the contractor finds the gap already filled, there's no cavity grant to claim.
What each means
Wall type and grant
| Main wall | Share of homes | No insulation recorded | Grant route |
|---|---|---|---|
| Cavity (filled or not) | 67% | 6% | Cavity grant, if the cavity is empty |
| Solid | 19% | 13% | Internal or external |
| Hollow block | 6% | 2% | Internal or external |
| Timber frame | 9% | 0% | Usually insulated when built |
Share of 549,459 BER certificates for homes built before 2011 with a known main wall type (SEAI BER register, our sums). 'No insulation recorded' is a share of all of them.
Cavity
If you have an empty cavity
Get it filled first. The grant is €1,300 on a semi-D against a median cost of €1,585 (SEAI median costs), and the higher rate is €1,700. cavitywallinsulation.ie covers the cavity job, bonded bead and if your house is suitable.
Solid or hollow block
If there's no cavity
You choose between internal insulation (dry lining) and external insulation. The comparison sets out the grant, cost, planning and space for each. Older and stone houses need more care: old, solid and stone walls.
Your grant
Your wall grant and a price, in 4 taps
Tap your home, which wall job you think it needs, when it was built and which rate fits you. Then leave your number and one SEAI-registered insulation contractor who covers your area rings you to look at the walls and price it in writing.
FAQ
Questions people ask
How do I know if I have cavity walls?
Your BER certificate records the wall type, or a contractor or architect can tell you (SEAI wall insulation guide). A cavity wall is two rows of brick or block with a gap between.
My cavity was filled years ago. Can I get another grant?
Not if it was filled with a government grant: SEAI funds wall insulation once per property (seai.ie).
Is hollow block the same as a cavity wall?
No. SEAI describes a cavity wall as two rows of brick or block with a gap between them (SEAI wall insulation guide); a hollow block wall is a single row of blocks, so there's no cavity to fill. Internal or external insulation is the route.
Keep reading
Related guides
- Internal wall insulation (dry lining)Dry lining: the grant, the cost, the room you lose and the rules.
- Internal vs external insulationSame solid wall, two jobs: grant, cost, planning and disruption.
- Wall insulation by countyWall types on 549,459 BER certificates, county by county.
- Old, solid and stone wallsPre-1940, stone and protected houses: what to check first.
- Wall insulation cost after the grantSEAI's median cost for each wall job, before and after the grant.
- Wall insulation grant amounts 2026All three wall grants, the higher cavity rate and what changed in 2026.
Where these numbers come from (6 public sources, checked 2 November 2026)
- SEAI, Homeowner's Guide to Wall Insulation (PDF)
- SEAI BER Research Tool, full public file (downloaded 29 October 2026, our sums)
- SEAI, individual energy upgrades: median costs and fixed grants, January to June 2026, 23,412 upgrades (PDF)
- SEAI, insulation grants page
- SEAI, wall insulation grant page
- Citizens Information, Better Energy Homes Scheme (page updated 22 October 2026)