How Much Does It Cost to Insulate a House?
The average cost of insulating your house costs from €2,000 to €4,000 depending on the size of your home, the material you choose and the extent of the project.
| Insulation | Estimated Cost |
|---|---|
| Attic | €400-€800 |
| Underfloor | €1,000-€1,500 |
| Cavity Wall Insulation | €700-€1,700 |
| External Wall Insulation | €17,900-€21,900 |
| Total Cost Estimate | €20,000-€26,000 |
If you choose not to have your external walls insulated, the total cost of insulating your home would be closer to between €2,000 to €4,000.
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Why Should I Insulate My Home?
- Boosts Comfort and Reduces Drafts: Insulation acts as a thermal barrier, eliminating cold spots and drafts.
- Increases Property Value: A high Building Energy Rating (BER) is a major selling point in the Irish housing market.
- Reduces Your Carbon Footprint: By reducing your reliance on fossil fuels for heating, you directly lower your home's carbon emissions.
- Soundproofing: Certain insulation materials can effectively dampen external noise from traffic and neighbours.
Are There Any Insulation Grants?
There are several SEAI grants available for those looking to improve the insulation of their homes. All homeowners whose homes were built and occupied before 2011 can apply.
| Type of Grant | Type of Home | Grant Value |
|---|---|---|
| Attic Insulation | Apartments | €800 |
| Mid-Terrace Home | €1,200 | |
| Semi-detached or End-Terrace | €1,300 | |
| Detached Home | €1,500 | |
| Cavity Wall Insulation | Apartments | €700 |
| Mid-Terrace Home | €800 | |
| Semi-detached or End-Terrace | €1,200 | |
| Detached Home | €1,700 | |
| External Wall Insulation | Apartments | €3,000 |
| Mid-Terrace Home | €3,500 | |
| Semi-detached or End-Terrace | €6,000 | |
| Detached Home | €8,000 |
All upgrades must be made by an SEAI Registered Contractor.
What Types of Insulation Are There?
The three main types of insulation are: attic insulation, wall insulation, and floor insulation.
Attic Insulation
As heat naturally rises, good roof insulation will help trap the heat longer in your living space. The SEAI calculates a home can lose 20-30% of its heat through its roof if not properly insulated. Insulating the attic of a 540 sq ft house would cost around €400-€600.
Cavity Wall Insulation
Cavity wall insulation is one of the most cost-effective ways to insulate your house. You can expect to pay between €7.50 - €10.50 per m2.
External Wall Insulation
It can cost up to €22,000 to fully insulate the external walls of a standard, semi-detached house.
Internal Wall Insulation
Internal wall insulation can cost around €80-€130 per square metre, bringing the total renovation cost between €6,300 and €12,000 for a typical semi-detached house.
Floor Insulation
Improperly insulated floors can add an additional 10% heat loss. Carpet prices range from €7-€32 per square metre. Polystyrene foam insulation can range from €24-€50 per square metre.
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Which Insulation Material Should I Use?
| Material | R-rating | Pros | Cons |
|---|---|---|---|
| Fibreglass Batt | 3.1-3.4 | Cheapest way to insulate | Not as good at filling gaps. Compresses over time. |
| Fibreglass Loose Fill | 2.2-4.3 | Great at filling all gaps | Health concerns regarding inhaling particles |
| Foam (Polystyrene Board) | 3.8-5.0 | Mid-priced | Needs to be cut very accurately |
| Spray Foam (Open Cell) | 3.5-3.6 | Effective air and vapour barrier | Expensive. R-ratings decrease over time. |
| Spray Foam (Closed Cell) | 6.0-6.5 | Highest R-rating for foam | Expensive. R-ratings decrease over time. |
| Sheep's Wool | 3.6-4.3 | Natural and biodegradable | Very expensive |
| Rockwool | 3.1-4.0 | Doesn't degrade over time | Costs more than fibreglass |
| Cellulose | 3.2-3.9 | Affordable and light | Not as effective as foam |