If you live in Ireland, you know how important it is to keep your home warm and energy-efficient. With rising energy prices and the Irish government offering grants for insulation, many homeowners are now choosing external wall insulation (EWI) to save money and improve comfort.
But one of the first questions people ask is: How much will it cost? That’s where an external wall insulation cost calculator comes in handy.
In this article, we will explain:
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What external wall insulation is
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Why it’s a smart investment
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What affects the cost
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How to estimate the price using a calculator
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Example price breakdown
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Available grants in Ireland
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Final tips for Irish homeowners
What is External Wall Insulation?
External wall insulation involves attaching a layer of insulating material to the outside of your home’s walls. This layer is then covered with a protective finish, like render or cladding. The result? Your home stays warmer in winter and cooler in summer.
This type of insulation is mostly used for solid wall homes – houses built before the 1940s that don’t have cavity walls.
Why Choose External Wall Insulation?
There are several benefits of insulating your walls from the outside:
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Lower heating bills – reduce energy loss by up to 35%
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More comfortable home – better indoor temperature control
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Improved appearance – new render can refresh your home’s look
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Reduced carbon emissions – better for the environment
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Increased property value – energy-efficient homes are in demand
Factors That Affect the Cost
The cost of external wall insulation in Ireland depends on several factors:
1. Size of Your Home
The bigger your house, the more wall surface there is to insulate. A small terraced house will cost less than a large detached house.
2. Wall Condition
If your walls are damaged or uneven, you may need extra preparation work, which adds to the cost.
3. Type of Insulation Material
Different materials (e.g. EPS, mineral wool, phenolic board) have different prices. EPS (expanded polystyrene) is commonly used and is generally more affordable.
4. Finish or Render Type
You can choose from plain, textured, or brick-effect finishes. The more decorative the finish, the higher the cost.
5. Location in Ireland
Prices may vary slightly depending on your county and the availability of contractors.
6. Access to Walls
If scaffolding is needed or access is difficult, this could increase the price.
External Wall Insulation Cost Calculator – How to Use It
An EWI cost calculator is an online tool that helps you estimate the cost of insulating your home. You simply enter a few basic details about your property, and the tool gives you an estimated price.
Here’s what most calculators ask for:
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Type of property (terraced, semi-detached, detached)
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Floor area in square metres or wall area
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Type of insulation material
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Finish preference (basic or decorative)
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County or location
Once you enter the data, the calculator shows:
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Estimated cost before grants
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Estimated cost after SEAI grant (if eligible)
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Estimated annual savings on energy bills
Example Cost Breakdown
Let’s look at a rough cost breakdown for a semi-detached house in Dublin:
| Feature | Details |
|---|---|
| House size | 100 m² wall area |
| Insulation type | EPS (100mm) |
| Finish | Standard render |
| Labour & materials | €90 per m² |
| Total before grants | €9,000 |
| SEAI grant (approx.) | €6,000 |
| Final cost to homeowner | €3,000 |
💡 Note: This is just an example. Your actual cost may vary depending on your specific situation.
SEAI Grants – Get Help with the Cost
In Ireland, the Sustainable Energy Authority of Ireland (SEAI) offers generous grants to homeowners who want to improve their home’s energy efficiency. As of 2025, you can get:
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Up to €6,000 for external wall insulation
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Grant amount depends on house type (apartments, mid-terrace, semi-detached, or detached)
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The home must be built before 2011
To get the grant, you need to:
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Use an SEAI-registered contractor
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Complete a BER (Building Energy Rating) assessment
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Meet all technical requirements
You can find the full details and apply at www.seai.ie.
Is It Worth It?
While the initial cost may seem high, external wall insulation pays off over time. With the SEAI grant, you could recover your investment in just a few years through reduced heating bills.
Plus, you get a warmer, more comfortable home – and help the environment too.
Tips Before You Start
Here are a few tips for Irish homeowners considering external wall insulation:
✅ Check for grants – Apply for SEAI funding before starting any work
✅ Compare quotes – Get at least 3 quotes from SEAI-approved contractors
✅ Ask for guarantees – Ensure the work comes with a warranty (often 10+ years)
✅ Look at previous work – Ask to see other homes the contractor has insulated
✅ Use a calculator – Estimate your costs and savings before deciding
Conclusion
External wall insulation is one of the best ways to improve your home’s energy performance in Ireland. It helps reduce heating costs, makes your home more comfortable, and supports a greener future.
By using a simple external wall insulation cost calculator, you can quickly understand what your project might cost – and how much you’ll save.
With SEAI grants available, there’s never been a better time to upgrade your home.
Thinking of insulating your home? Try an online cost calculator today and take the first step towards a warmer, more energy-efficient house.