Before you begin
What you need to check insulation grants
If you are claiming the first-time-buyer rate, check the purchase-date and existing-home conditions on SEAI first.
An apartment qualifies for attic support only where heat escapes through its own roof to outside.
Reading the answer
Understanding your insulation grant amounts
Each grant is a fixed amount for that measure and that kind of home. It is not a percentage of the contractor’s quote.
The grant figures are SEAI’s. The costs, savings and payback are Verdanyx estimates, and the result labels every one of them as such.
Where two measures’ estimated payback ranges overlap, the result says they cannot be separated instead of naming a winner. Two written quotes will separate them; this model cannot.
Boundaries
Assumptions and limitations
Working assumptions
- Official fixed grant values are current to the review date.
- Typical contractor costs and the share of the bill each measure saves are broad estimates, not official SEAI figures.
- The order measures appear in comes from those estimates, so it is a suggestion about where to get quotes rather than a ranking.
Where to be careful
- Prior grant history and supplementary wall-measure rules can change eligibility.
- The grant cannot exceed eligible costs and approval must precede works.
Worked example
The same question, answered end to end
An eligible semi-detached house built before 2011, cavity walls, nothing done yet, spending €1,800 a year on heating.
What was entered
- Eligible owner, home built and occupied before 2011, standard grant rates.
- Semi-detached with cavity walls.
- No attic, wall or heating-control work done yet.
- €1,800 a year spent on heating.
How it is worked out
Cavity walls mean three measures apply: attic insulation, cavity wall insulation and heating controls.
The fixed grants for a semi-detached house are €1,500, €1,300 and €700 — €3,500 together.
Attic insulation is modelled to cut 15% of €1,800, so about €270 a year.
Against a €1,200–€1,900 contractor range less the €1,500 grant, the cost after the grant is €0–€400, and payback runs from under a year to about 1.5 years.
Cavity fill is modelled the same way and lands at €0–€700 after its €1,300 grant, paying back in under a year to about 1.9 years.
Those two ranges overlap, so the result refuses to say which to do first and asks for quotes on both. The €3,500 of grants is the part of the answer that does not depend on the model.
What the tool returns
- Eligibility
- Likely eligible
- Measures shown
- 3
- Grants added together
- €3,500
- Largest single grant
- €1,500
Common questions
Questions about this tool
Can I get a second wall insulation grant?
Since 2 March 2026, yes — if the first one was not external wall insulation. A home that was grant-aided for cavity wall insulation can apply for internal or external; one that had internal can apply for external; external is the last measure and nothing follows it. It is one further measure, not both.
Why is the cutoff 2011 here but 2021 for solar and heat pumps?
SEAI uses different eligibility dates for different measures. Insulation requires the home to have been built and occupied before 2011.
Can a home receive a second wall measure grant?
Under current rules, some homes previously grant-aided for cavity or internal insulation can apply for a permitted supplementary wall measure.