Cavity wall insulation grant

SEAI cavity wall grant amounts

SEAI pays a fixed amount by home type. It doesn't depend on what your contractor charges. SEAI raised the cavity wall amounts on 3 February 2026, and open applications got the new amount (seai.ie).

Source: seai.ie wall insulation page, checked 28 October 2026. Older SEAI PDFs still show the lower pre-2026 amounts.

The higher rate: welfare, HAP and RAS

Homeowners who get a qualifying welfare payment can claim a higher fixed grant for cavity wall insulation: €2,300 for a detached house, €1,700 for a semi-D or end of terrace, €1,100 for a mid-terrace and €900 for an apartment. The same higher rate applies to properties in an active HAP tenancy or RAS arrangement. SEAI may ask for evidence, and applications may be audited. SEAI sets which welfare payments qualify (seai.ie).

Who can get it

• The home was built and occupied before 31 December 2010, and has an MPRN (seai.ie).
• You use a contractor on SEAI's register. If the contractor isn't listed, you can't get the grant (SEAI guide).
• SEAI makes you a grant offer before any work starts (seai.ie).
• All external walls of the home are fully insulated. SEAI calls this a whole-surface solution: partial insulation is not eligible (seai.ie).
• The insulated wall reaches a U-value of 0.27 W/m²K (SEAI guide).
• Traditional solid-wall homes are not covered by this grant. SEAI has a separate Traditional Homes pilot for them.

Planning permission is not required for internal or cavity insulation (seai.ie).

Building Regulations: if the work alters more than 25% of the home's surface area, the home must reach at least a B2 BER, or have its heating system and attic insulation brought up to Building Regulation standard.

Two ways to claim it

There are two routes. Apply yourself, and SEAI pays you the grant after the work. Or use a One Stop Shop, which manages the job and takes the grant off your price up front.

How the grant works, step by step

1. Find a registered contractor and get quotes.Use a contractor on SEAI's register. Get a written price with VAT.
2. Apply to SEAI for a grant offer.Through the standard application process. Accept the offer before any work starts.
3. The work is done.Usually in a day for a house. All external walls must be fully insulated.
4. Post-works BER.A BER assessor rates the home after the work.
5. Submit your evidence.Send SEAI the completed paperwork from the contractor and the BER.
6. SEAI pays the grant.The fixed amount, after the work. SEAI may inspect the work.

Source: seai.ie wall insulation page, checked 28 October 2026.

Start work before the grant offer and you lose the grant. Approval comes first, every time.

What it leaves you to pay

On SEAI's own median costs from 2025, the grant covers most of the job. A semi-D is typically about €200 after the grant, and a detached house about €450. The cost guide has every house type.

If the home already had a wall grant

SEAI says: "If your home has previously received a grant for wall insulation, you may now apply for a second wall insulation measure." A home that had a cavity wall grant can apply for internal or external insulation. A second cavity grant isn't available. See second wall insulation grant.

The other wall grants

If your walls can't be filled, SEAI also funds internal insulation (dry lining) and external insulation (the wrap). For a semi-D, those grants are €3,500 and €6,000 (seai.ie, checked 28 October 2026). They are bigger jobs. Compare the three wall grants.

Questions people ask