Insulation is the least glamorous home energy upgrade and almost always the smartest first move. It’s cheaper than solar or a heat pump, it cuts your heating bill immediately, and it’s what makes every other upgrade work better. This guide covers what insulation costs in Ireland, the SEAI grants by house type, and the order to do things in.
The essentials
- Attic insulation: €1,100–€2,000 grant · usually the best first win
- Wall insulation: €700 (cavity) up to €8,000 (external) grant
- Home generally must be built before 2011
- Insulate before installing a heat pump
Insulation grants by house type (2026)
SEAI insulation grants vary by home type. These are the standard maximum amounts:
| Measure | Apartment | Mid-terrace | Semi/End-terrace | Detached |
|---|---|---|---|---|
| Attic insulation | €1,100 | €1,400 | €1,500 | €2,000 |
| Cavity wall | €700 | €850 | €1,300 | €1,800 |
| Internal (dry lining) | €1,500 | €2,000 | €3,500 | €4,500 |
| External wall | €3,000 | €3,500 | €6,000 | €8,000 |
Note
Full cost and grant detail is in our guides to attic insulation and wall insulation.
Which insulation should you do first?
A sensible order for most homes:
- Attic insulation — cheapest, fastest, biggest bang for buck. Heat rises, so this is where you lose it.
- Cavity wall insulation — if your home has a suitable cavity, it’s quick and well-subsidised.
- External or internal wall insulation — for solid-wall homes, more expensive but a big improvement.
- Draught-proofing and heating controls — low-cost finishing touches.
Retrofit: doing it all at once
If you want to jump straight to a warm, efficient home, a deep retrofit through the SEAI One Stop Shop bundles several measures and aims for at least a B energy rating, with the grant deducted from the price upfront. It’s more money in one go, but one managed project. Compare the routes in One Stop Shop vs individual grants.
Why insulation comes before everything else
A well-insulated home:
- Costs less to heat, whatever your heating system.
- Is the prerequisite for a heat pump — see heat pumps (they need a low heat-loss home).
- Improves your BER, which matters when selling or renting.
Tip
Get a BER assessment first if you’re unsure where you stand. It shows exactly where your home is losing heat and helps you spend the grant money where it counts.
Note
This is general information, not financial advice. Grant amounts and eligibility change — confirm current figures with SEAI before you commit.