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The cavity wall grant for a detached house

A detached house gets €1,800 from SEAI for cavity wall insulation, or €2,300 on the higher rate. The job typically costs €2,350, so about €550 is left to pay, or about €50 on the higher rate. Every outside wall has to be insulated, and the home must have been built and first lived in before 2011.

The grant, the higher rate, the typical cost and what to check first.

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  • €1,800SEAI cavity wall grant
  • €2,300the higher rate
  • €2,350typical cost of the job
  • about €550left to pay at the standard rate
A white detached house with dormer windows in a field below a hill

The grant for this home

Standard rateHigher rate*
Cavity wall grant€1,800€2,300
Typical cost€2,350€2,350
Left to payabout €550about €50
Post-works BER, after its €50 grantabout €230about €230

* For homeowners on Fuel Allowance, Working Family Payment, One-Parent Family Payment, Domiciliary Care Allowance or Carer's Allowance (living with the person you care for), or Jobseeker's Allowance or Disability Allowance for over 6 months with a child under 7, and for landlords with a HAP or RAS tenant.

Why a detached house gets the most

Four outside walls means the most wall to fill, so SEAI sets the biggest fixed grant for a detached house. It's also where an empty cavity loses the most heat. 41% of households in Ireland live in a detached house (Census 2022), and in the western counties it's most of them.

Check your cavity wall grant

Four quick taps. You see your grant as you go, then what the job typically costs after it, the BER and your next step. Your number is only asked for at the end, if you want a price.

A detached house built before 2011, no earlier wall grant: a €1,800 grant, and the job typically costs €2,350, so about €550 is left to pay.

Step 1 of 6

What kind of home is it?

SEAI sets a fixed grant for each house type.

How this is worked out

SEAI pays a fixed cavity wall grant for each house type, and a higher fixed amount to homeowners on certain welfare payments and to landlords with a HAP or RAS tenant. The typical cost is the median price of cavity wall insulation for your house type across thousands of grant-funded jobs, and the post-works BER is its median price less its own grant. Your installer prices your walls after a look: it's a guide to plan with, never a quote. SEAI decides every grant.

Before you apply

  • Check the walls are cavity walls. Some detached houses, older ones especially, have solid or hollow block walls with no cavity. Those need internal or external insulation instead, which have their own grants.
  • Check for an earlier wall grant. One cavity wall grant per MPRN.
  • Count every wall. The grant needs every outside wall insulated, extensions included.

Add the attic

The attic grant for a detached house is €2,000, or €2,500 on the higher rate, against a typical attic job of €2,700. Both can go in one application: cavity and attic grants together.

Cavity Wall Insulation Grants guides & price breakdowns

Straight answers to what people ask most: itemised costs, specifications, planning or grants, and what to check before you book.

Cost & Pricing GuideWhat cavity wall insulation costs after the grantCavity wall insulation after the SEAI grant: about €285 on a semi-D, €550 detached, €400 mid-terrace. The BER and higher rate too.Read the guide →Grants & RegulationsWho qualifies for the cavity wall grantWho qualifies for the SEAI cavity wall grant: built and first lived in before 2011, an MPRN, no earlier wall grant, every wall done, approval first.Read the guide →Grants & RegulationsHow to apply for the cavity wall grantHow to apply for the SEAI cavity wall grant: online in minutes, accept within 30 days, work and BER within 8 months, paid in 4 to 6 weeks.Read the guide →Grants & RegulationsWhy cavity wall grants get refusedWhy SEAI cavity wall grants get refused: work before approval, built from 2011, an earlier wall grant, partial walls, no BER, the 8-month deadline.Read the guide →Grants & RegulationsStarted the work before the grant was approved?Work started before SEAI approved the cavity wall grant gets nothing, and neither do materials bought early. What to do now, and the right order.Read the guide →Grants & RegulationsCavity wall and attic grants togetherThe SEAI cavity wall and attic grants together: €2,800 for a semi-D, €3,800 detached, the BER, and what's left to pay.Read the guide →

More guides & resources: The BER after cavity wall insulation · Had a wall grant before? The second wall measure · All guides & calculator hub · Technical & trade glossary · Frequently asked questions · All areas covered

Questions people ask

How much is the cavity wall grant for a detached house?

€1,800, or €2,300 on the higher rate for homeowners on certain welfare payments and landlords with a HAP or RAS tenant.

What does it cost to insulate the cavity of a detached house?

Typically €2,350, so about €550 after the grant.

My detached house is built of hollow block. Can I get the cavity grant?

Not the cavity grant: hollow block walls have no cavity to fill. Internal or external wall insulation have their own grants.

Do all the walls have to be done?

Yes. SEAI needs every outside wall of the home fully insulated. Partial insulation isn't eligible.

Cavity Wall Insulation Grants across all 26 counties

Requests from all 26 counties go to one vetted local specialist who covers your county — from Dublin, Cork, Galway and Limerick to Kildare, Meath, Wicklow, Waterford and Donegal. Pick your county below for local prices, specifications and advice. Compare all areas covered →

A living room with a fire lit in a stone fireplace, an armchair and big windows

Check your cavity wall grant

Four taps to your grant and what's left to pay, then one SEAI-registered installer who covers your county rings with a price.

Get a free quote