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Attic, cavity and external wall insulation grants in Ireland (2026)

Last updated: · Figures checked 18 October 2026 · By the HouseWise team

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Insulation is usually the first upgrade to do. It's what makes a home warm enough for a heat pump, it's a condition of the new windows grant, and the attic is often the cheapest win of all: SEAI says a house loses an average of 20 to 30% of its heat through the roof (SEAI).

Grant amounts by house type

Standard SEAI grants, checked 18 October 2026 (attic, walls):

Insulation Apartment Mid-terrace Semi-D / end of terrace Detached
Attic €1,100 €1,400 €1,500 €2,000
Attic: first-time buyers, welfare, HAP/RAS €1,400 €1,800 €1,900 €2,500
Cavity wall €700 €850 €1,300 €1,800
Cavity wall: welfare, HAP/RAS €900 €1,100 €1,700 €2,300
Internal (dry lining) €1,500 €2,000 €3,500 €4,500
External (the wrap) €3,000 €3,500 €6,000 €8,000

What it costs, and what's left after the grant

These are SEAI's median costs from 23,412 grant-aided upgrades completed January to June 2026: half of jobs cost less, half cost more (SEAI median costs, PDF). "Left to pay" is the median cost minus the standard grant; your quote will differ.

Job Home Median cost Standard grant Left to pay
Attic Semi-D €2,101 €1,500 €601
Attic Detached €2,700 €2,000 €700
Cavity wall Semi-D €1,585 €1,300 €285
Cavity wall Detached €2,350 €1,800 €550
Internal (dry lining) Semi-D €9,843 €3,500 €6,343
External (wrap) Semi-D €23,219 €6,000 €17,219
External (wrap) Detached €26,500 €8,000 €18,500

The pattern is clear: attic and cavity insulation are close to free after the grant; dry lining and external insulation are big projects where the grant covers roughly a quarter to a third.

Which wall insulation is right?

  • Cavity wall: insulation is pumped into the gap between two leaves of block or brick from outside. Quick and cheap, but only works if your walls have an empty cavity. A contractor needs to check what your walls are made of first.
  • Internal (dry lining): insulated boards fixed to the inside of external walls. You lose a little floor space and rooms need redecorating, sockets moving and so on.
  • External (the wrap): insulation fixed to the outside and rendered over. Often the main option for solid-wall and hollow-block houses with no cavity to fill, and it changes how the house looks. You may need an ESB Networks service alteration if cables run on the wall.

Whole-surface rule: to get any wall grant, all external walls must be insulated. Doing one or two walls isn't eligible.

Planning: cavity and internal insulation don't need planning permission. Since 27 July 2026, external wall insulation up to 15 cm thick is exempt too, as long as it doesn't project onto a public road and the finish matches the house and street (Citizens Information). Protected structures and architectural conservation areas have extra restrictions.

Building Regulations: if the works affect more than 25% of your home's surface area, SEAI says the home must either reach at least a B2 BER, or have a heating system and attic insulation that meet the Building Regulation standard.

The second wall grant

Since 2 March 2026, if you already had a wall insulation grant you can apply for a second, better wall measure:

  • had cavity → you can now get internal or external;
  • had internal → you can now get external only;
  • had external → no second wall grant.

This is aimed at homes that had cheap cavity fills years ago and now want to be heat-pump ready.

Who qualifies

  • You own the home (owner-occupiers, landlords, holiday-home owners, companies and owner management companies, charities and approved housing bodies can all apply).
  • It has an MPRN and was built and occupied before 2011 (SEAI's wall page says on or before 31 December 2010).
  • You haven't already had a grant for that measure at that MPRN (other than the second wall measure above).
  • Apartments: the attic grant only applies to top-floor apartments, or where heat escapes through the roof.

Before you sign

  • Get at least two or three written quotes from SEAI-registered contractors, and check they're registered for that specific measure.
  • Apply for the grant and wait for your offer before work starts.
  • Book the post-works BER (SEAI pays €50 towards it). It's needed before the grant is paid.
  • Ask exactly what's included in the price, for example roof-space ventilation, access walkways and insulating pipes and tanks.

Add up the grants for your home with our grant estimator

FAQs

Is attic insulation free in Ireland? Not usually, but it's close. SEAI's median attic job for a semi-detached house cost €2,101 against a €1,500 grant. Homes on qualifying welfare payments built before 2006 may get it free through the Warmer Homes Scheme.

Can I get the grant for insulating just one wall? No. SEAI requires a whole-surface solution: all external walls must be insulated.

Does external insulation need planning permission? Since 27 July 2026, generally not if it's no more than 15 cm thick, doesn't project onto a public road and matches the finish of the house and street. Check with your council if your home is protected or in an architectural conservation area.

I bought my first home in 2026. Do I get more? Yes, for the attic only: up to €2,500 for a detached house if you bought on or after 1 January 2025 and the home was built and occupied before 2011.

Sources

All checked 18 October 2026.