Attic insulation is Ireland’s most widely recommended home energy upgrade. It’s low-cost, high-impact, and the SEAI grant covers most or all of the cost for many households.
SEAI grant amounts
| Dwelling type | Non-FTB | First-time buyer |
|---|---|---|
| Detached | €2,000 | €2,500 |
| Semi-detached / end-terrace | €1,500 | €1,900 |
| Mid-terrace | €1,400 | €1,800 |
| Apartment | €1,100 | €1,400 |
How much does installation cost?
Typical prices for a qualified SEAI contractor:
- Semi-detached (70–90 m² floor area): €800–1,200
- Detached (100–150 m² floor area): €1,200–2,000
- Large detached or complex roof: €1,500–2,500
With an SEAI grant of €1,500 for a semi-detached, the net cost is often under €300–500, making it one of the quickest payback upgrades available.
Types of attic insulation
Blown mineral wool (EPS or glasswool): the most common method. Quick to install, applied to a uniform depth, and better at filling corners and obstacles. Most SEAI contractors use this method.
Roll/batt mineral wool: quicker for DIY and cheaper material, but requires careful installation to avoid gaps and cold bridging. Can be topped up by a contractor for the grant.
Rigid boards: used in converted attics or where insulation goes between rafters rather than floor joists. Slightly more expensive.
What depth do I need?
If your attic already has 100mm of insulation (common in 1970s–1990s homes), topping up to 300mm qualifies for the grant and is typically even cheaper than a full install.
Current SEAI grant-eligible specification: minimum 300mm of mineral wool equivalent (or equivalent U-value ≤ 0.16 W/m²K).
Will it affect attic storage?
If you’re using the attic for storage, topping up insulation to 300mm on the floor reduces usable floor space slightly. Some installers can raise the storage floor level on battens over the insulation. Ask your contractor about this.
Energy saving
Attic insulation can reduce heat loss through the roof by 25–35% for a typical Irish home with poor existing insulation. Annual savings depend heavily on your current insulation level and heating costs, but a typical family home might save €150–350/year in heating costs.
How to apply for the grant
Apply at seai.ie/attic-insulation before works start. Contractors must be on the SEAI registered list. The application takes about 10 minutes.
Combining attic insulation with cavity wall insulation in the same application is common and can simplify the process.