What Is the Second Wall Insulation Grant?
From 2 March 2026, homeowners who previously received an SEAI grant for wall insulation can now apply for a second wall insulation measure. This is designed for homes where cavity fill alone wasn't enough to achieve good thermal performance.
For example, if you had cavity wall insulation pumped in years ago but your home still feels cold (especially on exposed walls), you can now add external or internal insulation and claim a new grant for it.
Grant Amounts
| Measure | Detached | Semi-D / End | Mid-Terrace | Apartment |
|---|---|---|---|---|
| External wall insulation | €8,000 | €6,000 | €3,000 | €3,000 |
| Internal wall insulation | €4,500 | €3,500 | €2,000 | €1,500 |
These are the same grant amounts as for a first wall insulation measure. The key difference is that you're now eligible even if you've already claimed a wall insulation grant before.
Who Is Eligible?
- You must have previously received an SEAI grant for wall insulation (cavity, external, or internal)
- The second measure must be a different type from the first (e.g. cavity first, then external)
- Standard SEAI eligibility criteria apply (home built before relevant date, SEAI-registered contractor)
- Available from 2 March 2026 through both individual grants and One Stop Shop routes
Why Add a Second Layer?
Cavity wall insulation fills the gap between the inner and outer leaf of the wall. It's effective but limited by the cavity width (typically 50–100mm). Adding external or internal insulation on top creates a thicker, more continuous insulation layer that:
- Eliminates thermal bridges at wall junctions, around windows, and at floors
- Can improve BER by 1–3 additional ratings
- Makes the home eligible for a heat pump (HLI requirement of 2.0 or lower)
- Qualifies the home for the windows and doors grant (HLI of 2.3 or lower)
A BER assessment shows whether your existing insulation is performing well or if a second wall measure would make a significant difference. It also confirms your HLI, which you'll need for windows/doors and heat pump grants. Book a BER with Homerating.ie →
Frequently Asked Questions
Yes. This grant is specifically for homes that already received an SEAI grant for wall insulation and want to add a second layer for better performance.
Yes. Many homes with cavity fill still lose significant heat through thermal bridges. Adding external insulation on top creates a continuous insulation envelope and dramatically improves comfort and BER.