“How much does insulation cost?” is the first question at every assessment, and the honest answer is a set of ranges, not one number. This page puts every insulation type side by side: what drives the cost, what the SEAI grant covers for each, and the order that makes a budget work hardest. Use it as the map, then follow the deep-dive guide for the measure that fits your house.
- Cheapest measures
- Attic & cavity walloften a few hundred euro net after grants
- Biggest investment
- External wall insulationfive figures before its €3,000 to €8,000 grant
- Grant support
- Every major measurefixed SEAI amounts by home type
- Best order
- Attic → walls → floorsfastest payback first
- Exact price
- Set by your housea free survey turns ranges into a figure
Every measure, side by side
| Atticbest value | Cavity | Internal | External | |
|---|---|---|---|---|
| Cost level | Lowest | Low | Mid to high | Highest |
| SEAI grant | Up to €2,500 | Up to €2,300 | €1,500 to €4,500 | €3,000 to €8,000 |
| Time on site | A morning | A day | Days, room by room | Weeks, scaffolded |
| Suits | Every house | Cavity-wall homes | Solid walls, inside route | Solid walls, whole-house |
| Payback | Fastest | Fast | Medium | Longest, biggest change |
The deep dives, with the full numbers for each: attic insulation, cavity wall insulation, internal wall insulation and external wall insulation. Floor insulation completes the envelope and is usually priced alongside other works at a survey.
What actually drives the price
Two identical-looking quotes can hide very different jobs. These are the four things that honestly move the number:
Size and shape of the house
More wall and roof area means more material and labour. A dormer bungalow and a two-storey semi with the same floor area can price very differently.
Wall construction and condition
Cavity or solid, render condition, and any repairs needed first. The right method follows the wall, and so does the cost.
Access and detailing
Scaffolding, awkward gables, window reveals and junctions. Good detailing is where the performance lives, and it takes time.
Making good the finish
Plastering, reveals, sills and paint after the insulation goes in. Cheap quotes often quietly leave this out; complete ones include it.
Estimate your grant support
The grants are fixed amounts by measure and home type, so you can get a feel for the support before anyone visits:
Book a free assessment for your exact figure.
Spend the budget in the right order
The order is the same whatever the budget: attic first, because nothing else buys as much warmth per euro. Cavity walls next where the house has them. The bigger wall measures after that, floors and draughts alongside, and the heating system last, once the fabric is warm enough to let a smaller, cheaper system do the job. That sequence is the heart of a complete home insulation plan, and it is how the SEAI grants are designed to be stacked.
Questions people ask
Why won’t anyone give me an exact price over the phone?
Because the honest price follows the building. Wall type, condition, access and finish decide the real number, and a five-minute call cannot see any of them. A free survey can, and then the figure is real.
Do prices include the grant already?
Practice varies, which makes quotes hard to compare. We price the job and show the grant separately, so you see the gross cost, the SEAI support and your net figure on one page.
Is it cheaper to do everything at once?
Usually, yes. Shared scaffolding, one mobilisation and one making-good phase cost less than three separate projects. But phasing in the right order works too, and the attic never regrets going first.
Does insulation add value to the house?
A better BER is now a real factor in sales and rentals, and a warm, dry, efficient house shows it. Combined with the yearly bill savings, insulation is one of the few works that pays in comfort, running costs and resale at once.
The bottom line
Insulation pricing is simple once you see the pattern: attic and cavity are cheap, fast and mostly covered by grants; wall insulation is the bigger investment with the bigger transformation; and the right order, attic first, makes every euro work hardest. The exact figure for your house takes one visit.
If you are in Cork or anywhere in Munster, book a free home energy assessment. We survey the house, price each measure with its grant, and hand you the full picture in writing.
