Insulation Ireland
RetrofitIreland.ie provides insulation across Ireland, delivered by SEAI-registered contractors. Attic, cavity wall, external wall, and internal wall insulation, with SEAI grants covering up to 80% of the cost for attic and cavity wall insulation.
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What Home Insulation Involves
Home insulation is the installation of thermal material in the roof, walls, or floor of a house to reduce heat loss. An uninsulated Irish home loses 20 to 35 percent of its heat through the roof and up to 35 percent through the walls.
Insulation reduces the rate of heat transfer by trapping air within material layers, measured as a U-value in watts per square metre per kelvin (W/m²K). Lower U-values mean less heat escapes. SEAI administers grants covering the majority of the cost for most insulation types.
Insulate before upgrading your heating. SEAI requires a Heat Loss Indicator (HLI) of 2.3 or better before approving a heat pump grant. Insulation brings the HLI down. A heat pump sized for an insulated home runs more efficiently and qualifies for the full €12,500 grant.
Attic Insulation
Attic insulation reduces roof heat loss by up to 20 percent. The work involves laying mineral wool quilt or rigid board on the attic floor to a depth of at least 300mm. Most attic insulation jobs take one day.
| House Type | Typical Cost | SEAI Grant | You Pay |
|---|---|---|---|
| Detached | €2,000–€2,500 | €2,000 | €0–€500 |
| Semi-detached | €1,500–€2,000 | €1,300 | €200–€700 |
| Mid-terrace | €1,000–€1,500 | €1,200 | €0–€300 |
| Apartment (top floor) | €600–€1,000 | €800 | €0–€200 |
First-time buyers (home purchased on or after 1 January 2025) and homeowners on qualifying welfare payments receive up to €2,500 regardless of house type. SEAI estimates the attic insulation grant covers approximately 80 percent of the average cost.
Cavity Wall Insulation
Cavity wall insulation fills the gap between the inner and outer walls with bonded bead or mineral fibre, injected through small drilled holes. Most Irish homes built between the 1930s and early 2000s have cavity walls with a 50mm to 100mm gap. The work takes half a day to a full day.
| House Type | Typical Cost | SEAI Grant | You Pay |
|---|---|---|---|
| Detached | €1,500–€2,500 | €1,800 | €0–€700 |
| Semi-detached | €1,100–€1,500 | €1,200 | €0–€300 |
| Mid-terrace | €800–€1,200 | €800 | €0–€400 |
| Apartment | €600–€900 | €700 | €0–€200 |
Homeowners on qualifying welfare payments receive up to €2,300. A cavity survey is required before work begins. The contractor checks the cavity width, wall condition, and suitability for injection. This survey is typically free.
From March 2026, SEAI allows a second wall insulation measure. Homeowners who previously received a cavity wall or internal wall insulation grant can now apply for external wall insulation at standard grant rates.
External Wall Insulation (EWI)
External wall insulation wraps the outside of the house in high-density insulation boards, reinforced with fibreglass mesh and finished with a weather-resistant silicone render. EWI eliminates cold bridges, keeps internal walls warm, and gives the house a new exterior finish.
| House Type | Typical Cost | SEAI Grant | You Pay |
|---|---|---|---|
| Detached | €15,000–€24,000 | €8,000 | €7,000–€16,000 |
| Semi-detached | €13,000–€19,000 | €6,000 | €7,000–€13,000 |
| Mid-terrace | €8,800–€12,800 | €4,500 | €4,300–€8,300 |
| Apartment | €6,000–€10,000 | €3,000 | €3,000–€7,000 |
EWI costs €100 to €180 per square metre installed. The price depends on insulation board type (EPS is cheapest, mineral wool costs more), render finish, scaffolding access, and wall condition. The SEAI grant covers 20 to 35 percent of the median EWI project cost.
EWI is the most expensive insulation measure but delivers the most significant thermal improvement. Combining EWI with attic insulation can move a home from BER F or G to BER B.
Internal Wall Insulation (Dry Lining)
Internal wall insulation applies insulated plasterboard to the inside face of external walls. IWI typically costs €4,000 to €10,500 before grants. SEAI grants range from €2,000 (apartment) to €4,500 (detached).
IWI is cheaper than EWI but requires emptying rooms, moving electrical sockets and switches, and full redecoration after completion. IWI also reduces room dimensions slightly. Where budget allows, EWI delivers better thermal performance with no loss of internal space.
Which Insulation Should You Do First?
The recommended sequence for most Irish homes. Start with the cheapest, highest-impact measure and work outward.
Attic Insulation First
Cheapest measure. Highest grant coverage (up to 80%). Biggest immediate comfort improvement. If your attic has less than 300mm of insulation, do this before anything else.
Cavity Wall Insulation Second
If your home has suitable cavity walls, this is the next highest-value upgrade. The SEAI grant covers most or all of the cost for many homes. Half-day job, minimal disruption.
External Wall Insulation Third
The most expensive measure but the biggest long-term thermal improvement. Consider EWI if your home has solid walls, failed cavity fill, or if a deep retrofit to BER B is the goal.
Then Upgrade Your Heating
Once insulation is complete, your home qualifies for the SEAI heat pump grant of up to €12,500. A heat pump sized for an insulated home runs more efficiently and costs less to operate.
How Insulation Works Through RetrofitIreland.ie
SEAI-registered contractors survey the property, quote the work, and complete the installation.
Select Your Upgrades
Choose insulation (and any other measures) on the RetrofitIreland.ie quote form. Specify your house type, year built, and county.
Receive Contractor Details
RetrofitIreland.ie sends your enquiry to SEAI-registered insulation contractors in your area. Contractors contact you directly to arrange a survey.
Get a Survey and Quote
The contractor visits your home, assesses the walls, attic, and access, and provides a written quote including grant deductions.
Apply to SEAI
Apply online at seai.ie before any work begins. Approval is typically issued within minutes. Do not allow work to start before approval is confirmed.
Complete the Works
The SEAI-registered contractor carries out the insulation. Attic and cavity wall jobs typically take one day. EWI takes one to three weeks.
Post-Works BER Assessment
An SEAI-registered BER assessor visits after completion. SEAI pays a €50 contribution toward the assessment cost (€280 for welfare recipients).
Claim the Grant
Submit paperwork to SEAI. The grant is paid directly into your bank account within 4 to 6 weeks.
Risks, Exclusions, and Limitations
Must apply before work starts. Starting insulation before SEAI grant approval permanently disqualifies the grant for that measure. There are no exceptions.
Build Date Cut-Off
The home must have been built and occupied before 2011. Newer homes do not qualify for insulation grants.
SEAI-Registered Contractor Required
Using an unregistered contractor means no grant and potentially substandard work. Verify registration on the SEAI contractor list before proceeding.
Cavity Wall Suitability
Not all homes have suitable cavities. Homes built before the 1930s typically have solid walls with no cavity. Homes with very narrow cavities (under 50mm) or hollow block construction may not be suitable for standard injection. The contractor identifies this during the free cavity survey.
Ventilation After Insulation
Insulating a home without addressing ventilation can cause condensation and mould. Homes insulated to a high standard may need mechanical ventilation (MVHR) or demand-controlled ventilation, particularly after EWI.
EWI Planning Permission
Most standard EWI does not require planning permission. Homes in Architectural Conservation Areas or protected structures may need local authority approval before work begins.
Floor Insulation
Floor insulation is not covered by a standalone SEAI Better Energy Homes grant. Floor insulation may be included in a One Stop Shop deep retrofit package.
Insulation Questions
Get Your Free Insulation Quote
Get a free insulation quote from SEAI-registered contractors near you. Fill in your details and a contractor in your area will contact you directly with a survey and written quote.
SEAI-Registered Insulation Contractors Across Ireland
RetrofitIreland.ie covers all 26 counties. Select your county below to see contractors in your area.
Carlow
Carlow Town, Muinebheag, Tullow, Hacketstown, Borris, Bagenalstown, Rathvilly
Cavan
Cavan Town, Bailieborough, Belturbet, Virginia, Cootehill, Kilnaleck, Kingscourt
Clare
Ennis, Shannon, Kilrush, Killaloe, Ennistymon, Lisdoonvarna, Miltown Malbay, Scarriff, Sixmilebridge
Cork
Cork City, Ballincollig, Carrigaline, Midleton, Mallow, Cobh, Fermoy, Clonakilty, Bantry, Kinsale, Youghal, Bandon, Skibbereen, Macroom, Mitchelstown
Donegal
Letterkenny, Donegal Town, Bundoran, Buncrana, Ballyshannon, Ballybofey, Dungloe, Killybegs, Glenties, Carndonagh
Dublin
Swords, Lucan, Blanchardstown, Tallaght, Clondalkin, Malahide, Finglas, Ballymun, Coolock, Howth, Balbriggan, Dundrum, Rathfarnham, Dun Laoghaire
Galway
Galway City, Tuam, Ballinasloe, Loughrea, Athenry, Gort, Clifden, Oranmore, Moycullen, Headford
Kerry
Tralee, Killarney, Listowel, Kenmare, Dingle, Cahersiveen, Killorglin, Castleisland, Ballybunion
Kildare
Naas, Newbridge, Kildare Town, Celbridge, Leixlip, Maynooth, Athy, Clane, Kilcullen, Monasterevin, Rathangan, Castledermot
Kilkenny
Kilkenny City, Thomastown, Callan, Castlecomer, Graiguenamanagh, Urlingford
Laois
Portlaoise, Mountmellick, Mountrath, Abbeyleix, Rathdowney, Stradbally, Portarlington
Leitrim
Carrick-on-Shannon, Manorhamilton, Drumshanbo, Mohill, Ballinamore
Limerick
Limerick City, Castletroy, Newcastle West, Rathkeale, Abbeyfeale, Kilmallock, Adare, Askeaton
Longford
Longford Town, Granard, Edgeworthstown, Ballymahon, Lanesborough
Louth
Dundalk, Ardee, Carlingford, Termonfeckin, Blackrock, Dunleer, Tallanstown
Mayo
Castlebar, Ballina, Westport, Claremorris, Ballinrobe, Swinford, Belmullet, Kiltimagh, Charlestown
Meath
Navan, Drogheda, Ashbourne, Trim, Dunshaughlin, Ratoath, Laytown, Kells, Enfield, Oldcastle, Slane, Dunboyne
Monaghan
Monaghan Town, Carrickmacross, Castleblayney, Clones, Ballybay
Offaly
Tullamore, Birr, Edenderry, Clara, Portarlington, Banagher, Ferbane
Roscommon
Roscommon Town, Boyle, Castlerea, Strokestown, Ballaghaderreen, Elphin, Athlone
Sligo
Sligo Town, Ballymote, Tubbercurry, Enniscrone, Collooney
Tipperary
Clonmel, Thurles, Nenagh, Tipperary Town, Carrick-on-Suir, Roscrea, Cahir, Cashel, Templemore, Borrisokane
Waterford
Waterford City, Tramore, Dungarvan, Lismore, Portlaw, Kilmacthomas, Cappoquin, Tallow
Westmeath
Mullingar, Athlone, Moate, Kilbeggan, Kinnegad, Delvin, Castlepollard
Wexford
Wexford Town, Gorey, New Ross, Enniscorthy, Bunclody, Rosslare, Ferns, Courtown, Kilmore Quay, Taghmon
Wicklow
Bray, Greystones, Wicklow Town, Arklow, Blessington, Enniskerry, Baltinglass, Kilmacanogue
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