Walls are the second big place homes lose heat after the attic. There are three ways to insulate them, at very different price points — and the right one depends on how your home is built. Here are the SEAI grants and how to choose.
Short answer
Wall insulation grants range from €700 (cavity, apartment) up to €8,000 (external, detached). Cavity is cheapest where suitable; external performs best but costs most.
Wall insulation grants by type and house (2026)
| Type | Apartment | Mid-terrace | Semi/End-terrace | Detached |
|---|---|---|---|---|
| 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
Higher cavity-wall amounts apply for people on qualifying welfare payments. Confirm your figure on the SEAI wall insulation page.
Which type suits your home?
- Cavity wall insulation — for homes with a suitable gap between two layers of wall (many homes from the 1940s–2000s). Cheapest and quickest; injected in a day.
- Internal (dry lining) — insulated boards fixed to the inside of external walls. For solid-wall homes; reduces room size slightly and needs redecoration.
- External wall insulation — a insulating layer and render on the outside. Best performance and no lost internal space, but the most expensive and it changes the look of the house.
How to choose
- Find out how your walls are built — a BER assessment or a contractor survey will tell you if you have a cavity.
- Cavity first if you have it — best value by far.
- Solid walls? Weigh internal vs external on budget, disruption and appearance.
- Do the attic first if it isn’t already done.
Wall insulation is one of the biggest levers for improving your BER and getting a home ready for a heat pump.
Note
This is general information, not financial advice. Grant amounts and eligibility change — confirm current figures with SEAI before you commit.