Heat loss and payback
Is attic insulation worth it?
Yes, for most Irish houses. SEAI puts the heat lost through an uninsulated roof at 20% to 30% of a home's heat. Bringing a bare attic up to SEAI's standard cuts the heat going through the ceiling by about 93%, and after the grant a semi-D typically pays €300 to €600.
The figures, from SEAI and from 586,283 BER certificates for Irish houses built before 2011.
Free, no obligation. One SEAI-registered contractor prices it, not five.
- €2,000SEAI attic grant for a detached house
- €2,500at the higher rate
- €300 to €600typically left to pay on a semi-D
- 300 mmof wool: what SEAI's standard takes
Grant check
Your attic grant and what's left to pay
Two taps: your home, and which rate fits you. The answer is SEAI's fixed grant and its own median cost for the job.
Your SEAI attic insulation grant
€1,500
- SEAI median cost, Jan to Jun 2026
- €2,101
- Left to pay at the median
- €601
SEAI's fixed grant for a semi-d or end of terrace at the standard rate is €1,500. SEAI's median cost for attic insulation on a semi-d or end of terrace from January to June 2026 was €2,101. €2,101 less €1,500 leaves about €601. 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 home type and rate, as Citizens Information lists it. The median cost is SEAI's own figure from grant-funded attic jobs completed between January and June 2026; 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, the contractor must be on SEAI's register, and SEAI must approve the grant before work starts. It's an estimate, never a quote.
Heat loss
How much heat goes out through the roof?
Between 20% and 30% of a home's heat, if the roof isn't insulated. Heat rises, and the ceiling is a big, thin surface. SEAI's own example of a bare attic records a U-value of 2.3; the standard the grant pays for is 0.16. The lower the U-value, the less heat gets through.
586,283 certificates for houses built before 2011, grant BERs left out, from SEAI's public BER file. Every county.
How much less
How much less heat after insulation?
About 93% less through the ceiling for a bare attic, and about 41% less for a typical one. Heat through the ceiling goes up and down with its U-value, so the cut is the drop in U-value.
| Your attic now | U-value now | At SEAI's standard | Heat through the ceiling cut by |
|---|---|---|---|
| Bare, no insulation | 2.3 | 0.16 | about 93% |
| The median pre-2011 Irish house | 0.27 | 0.16 | about 41% |
| Already at standard | 0.16 or better | 0.16 | Little to gain |
The roof is one part of the house: walls, windows and floors lose heat too.
Savings
How much will attic insulation save me a year?
SEAI's homeowner's guide gives an example: 300 mm of glass wool in the attic saving over €250 a year on a €1,600 heating bill. Your own saving depends on what's up there now, how you heat the house and how warm you keep it. A bare attic saves the most; a top-up over 150 mm saves less.
Payback
How long does attic insulation take to pay back?
About 1 to 2.4 years for a semi-D on SEAI's example saving. After the standard grant a semi-D typically pays €300 to €600; at €250 a year that comes back in 1.2 to 2.4 years. A top-up over existing insulation saves less, so it takes longer.
At the higher rate, for certain welfare recipients, HAP and RAS landlords and first-time buyers, the grant covers more: see grant amounts.
BER
Does attic insulation improve my BER?
Yes, the roof's figure on the BER improves, and the grant needs a new BER after the work. How far the letter moves depends on the rest of the house: walls, windows and the heating system count too. Ask the contractor how the job should affect your BER.
Your grant
Your attic grant and a price, in 4 taps
Tap your home, when it was built, what's in the attic now and who you are. Then leave your number and one SEAI-registered insulation contractor who covers your area rings you to look at the attic and price it in writing.
FAQ
Questions people ask
Is attic insulation worth it in Ireland?
For most houses, yes. Up to 30% of a home's heat goes out through an uninsulated roof, and after the grant a semi-D typically pays €300 to €600.
How much heat is lost through the roof?
20% to 30% of a home's heat when the roof isn't insulated.
How much can attic insulation save?
SEAI's example: over €250 a year on a €1,600 heating bill, with 300 mm of glass wool.
Is it worth topping up attic insulation?
Usually, if you're below 300 mm. The median pre-2011 Irish roof is at 0.27; bringing it to 0.16 cuts the heat through the ceiling by about 41%.
Keep reading
Related guides
- Attic insulation costSEAI's median cost by home type, before and after the grant.
- Attic insulation grant amounts 2026Every attic grant rate in one table, and what changed in 2026 by date.
- How thick should attic insulation be?300 mm, 200 mm, blown wool or boards: what reaches SEAI's standard.
- Attic insulation by countyRoofs on 586,283 BER certificates, county by county.