Maximising comfort, efficiency and environmental impact

Insulating your home is one of the most cost‑effective improvements you can make. The “best” insulation varies depending on your property type, region and goals—whether that’s reducing heat loss, cutting energy bills, soundproofing, or opting for eco‑friendly methods. This guide delves into the top insulation types, explores what makes them stand out, and helps you choose the ideal solution for your house.

Why Insulation Matters

• Energy savings: Nearly 30% of domestic heat is lost through walls, roof and floors. Effective insulation can slash energy use, often paying for itself within a few years.
• Comfort all year round: Insulation delivers more stable indoor temperatures, reducing draughts in winter and overheating in summer.
• Noise reduction: Certain insulation materials double as sound barriers, improving comfort in noisy environments.
• Environmental impact: Lower energy consumption means fewer carbon emissions—especially important amid rising climate concerns.
• Property value: A well-insulated home scores higher on EPCs (Energy Performance Certificates), which can enhance resale value and appeal.
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Key Factors in Choosing Insulation

1- Thermal Performance (R‑value / U‑value)

Insulation’s ability to resist heat flow is measured by R-value (higher = better). Wall U‑values indicate heat transfer through structural elements—lower is better. Always check these ratings.

Building Type & Age

• New builds typically have cavity walls and accessible lofts—making kit-style insulation efficient.
• Older homes may have solid walls requiring internal or external treatment. Features like Victorian sash windows or heritage materials need special care.
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2- Moisture & Ventilation

Damp can undermine insulation and cause mould. Use breathable materials (e.g. mineral wool) and ensure proper vapour barriers and ventilation to protect structural integrity.

3- Environmental & Health Considerations

Plant-based insulations (cork, wood fibre) have low embodied carbon, while recycled cellulose and sheep’s wool perform well and are kind to indoor air quality.

4- Budget & Long‑term Savings

Higher-efficiency insulation like spray foam or rigid boards may cost more upfront but deliver better savings over time. Always consider Total Cost of Ownership (TCO).

Main Insulation Types

1- Loft & Roof Insulation

Heat loss through the roof is the largest single drain on energy. 

Two approaches dominate:

A- Cold‑Loft Insulation

• Placed between and over joists, preventing warm air from escaping the living space below.
• Materials: Mineral wool rolls, rigid PIR/PUR boards, loose-fill urea-formaldehyde.
• Pros: Cost-effective, easy to retrofit.
• Cons: Doesn’t insulate the loft space itself—loft remains cold.

B- Warm‑Roof Insulation

• Applied under rafters or above roofing felt—ideal for converted lofts.
• Materials: PIR/PUR boards, spray foam, wood fibre boards.
• Pros: Warms the loft room; higher U‑value.
• Cons: More expensive; needs expert installation.
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2- Cavity‑Wall Insulation

PVC walls with internal cavities offer a perfect spot to inject insulation.

Types:

• A- Blown mineral fibre: Glass wool or rock wool – cost-effective but requires large cavities.
• B- Expanded polystyrene beads: Lightweight, decent U‑value.
• C- Injected polyurethane foam: Excellent insulation and air seal, but more expensive.

Considerations:

• Ideal for properties built post‑1930s in the UK.
• Must assess cavity condition (free of debris/moisture) prior to installation.
• Affordable and disruptive-free solution, delivering great long-term savings.
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3- Solid‑Wall Insulation

Often found in pre‑1930 homes with no cavities.

External Wall Insulation (EWI)

• Rigid insulation panels (EPS, mineral wool, phenolic) are fixed externally and then rendered.
• Benefits: Retains internal space, improves insulation and external aesthetics in one go.
• Drawbacks: Planning permission may be required in conservation areas; costlier upfront.

Internal Wall Insulation (IWI)

• Options include insulated plasterboard, timber stud & mineral wool, or PIR boards.
• Benefits: Less external disturbance, useful for flats or rented properties.
• Drawbacks: Reduces room space and can complicate wiring & plasterwork.

   

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4- Floor & Basement Insulation

Ground floors leak up to 15% of heat—insulating them is often overlooked but effective.

Suspended Timber Floors

• Insulate between joists with mineral wool or recycled cellulose.
• Helps reduce draughts and cold air infiltration.

Solid Concrete Floors

• Insulation options: Rigid boards on top, under screed or insulation below slab.
• Suitable for new builds or major refurbishments.

Acoustic & Sound Insulation

• Ideal for shared walls or near busy roads.
• Combine insulation (rock wool or varying density boards) with acoustic plasterboard and seal all gaps to reduce noise.
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• Natural vs Synthetic Materials

Natural Insulation

• Sheep’s Wool: Renewable, breathable, and safe to handle. Good for moisture regulation.
• Wood Fibre: Excellent for external wall insulation, environmentally friendly.
• Cellulose: Recycled paper, treated for fire resistance, great thermal properties.

Synthetic Insulation

• PIR Boards (Polyisocyanurate): High thermal resistance, thin and efficient.
• EPS/XPS (Polystyrene): Lightweight and affordable, commonly used in wall and floor systems.
• Spray Foam: Air-tight and very efficient, but less eco-friendly and more costly.
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Best Insulation for Different Areas of the House

1. Loft Insulation: Mineral wool or rigid boards, depending on whether the loft is used for storage or living space.
2. Walls Insulation: Cavity insulation for newer homes; external or internal insulation for older properties.
3. Floors Insulation: Mineral wool for suspended timber; rigid boards for solid concrete.
4. Basements and Cellars: Use moisture-resistant boards like XPS or closed-cell foam.
5. Extensions and Conversions: Combine multiple materials to meet modern building standards.
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Installation: DIY or Professional?

• DIY-Friendly: Mineral wool rolls in lofts, floor insulation in accessible spaces.
• Professional Required: Cavity wall filling, external wall systems, spray foam insulation.

A professional installer ensures the insulation complies with regulations, is safely applied, and delivers maximum efficiency.

Cost and Value Considerations

• Loft Insulation: £300–£600 with a payback in 2–3 years.
• Cavity Wall Insulation: £700–£1,200 with long-term savings of up to £250 annually.
• Solid Wall Insulation: £8,000–£12,000 but offers major improvements in comfort and energy performance.
• Floor Insulation: Around £1,500 for suspended floors.

Grants may be available through schemes like SEAI in Ireland, reducing upfront costs significantly.

How to Choose the Right Insulation for Your Home

Start by conducting a home energy audit or thermal imaging survey. Prioritise areas with the greatest heat loss, then compare materials based on performance, price, and sustainability. If unsure, consult a qualified energy assessor or insulation specialist.

Conclusion

The best type of insulation depends on your home’s age, structure, location, and your goals—whether reducing energy bills, increasing comfort, or improving your EPC rating. From lofts and walls to floors and basements, each part of your home requires tailored insulation solutions. When chosen and installed correctly, insulation becomes a smart, sustainable investment that pays dividends for years.

Whether you’re planning a retrofit or building a new extension, taking time to choose the right insulation will make your home warmer, greener and more cost-effective.

If you’re ready to improve your home’s energy efficiency, OSBER offers expert insulation services across Dublin, Kildare, Meath, and Wicklow. From attic and wall insulation to ventilation solutions, our team delivers fast and high-quality installations. Contact us today to schedule your consultation and start saving on energy costs.