Older homes often come with charm, character, and history—but they also tend to be less energy-efficient than modern constructions. One of the biggest challenges homeowners face is maintaining warmth in winter and coolness in summer without skyrocketing energy bills. External wall insulation (EWI) is a popular solution, but is it worth the investment for older properties?
In this blog, we’ll explore the benefits, costs, potential drawbacks, and long-term value of external wall insulation for older homes to help you decide if it’s the right choice.
What Is External Wall Insulation?
External wall insulation involves adding an insulating Loft Insulation layer to the outside of a building, followed by a protective render or cladding. Unlike internal insulation (which reduces interior space), EWI wraps the entire house in a thermally efficient barrier.
How It Works:
Insulation boards (made of materials like EPS, mineral wool, or phenolic foam) are fixed to the exterior walls.
A reinforcing mesh is applied for durability.
A weather-resistant finish (render, brick slips, or cladding) is added for protection and aesthetics.
Benefits of External Wall Insulation for Older Homes
1. Improved Energy Efficiency
Older homes, especially those with solid walls (common in pre-1930s properties), lose heat rapidly. EWI reduces heat loss by up to 35%, leading to lower heating bills and a more comfortable living environment.
2. Enhanced Thermal Comfort
By eliminating cold spots and drafts, EWI helps maintain consistent indoor temperatures, reducing reliance on heating systems.
3. Weatherproofing Protection
EWI acts as a shield against rain, wind, and temperature fluctuations, preventing dampness and structural damage common in older buildings.
4. No Loss of Internal Space
Unlike internal insulation, EWI doesn’t reduce room sizes—a major advantage for smaller older homes.
5. Modernized Appearance
Older homes can look dated or worn. EWI allows for a fresh, modern finish with various textures and colors, boosting curb appeal.
6. Increased Property Value
Energy-efficient homes are in high demand. EWI can increase a property’s value by improving its Energy Performance Certificate (EPC) rating.
7. Reduced Condensation Mold
By keeping walls warmer, EWI minimizes condensation—a common issue in poorly insulated older homes.
Potential Drawbacks of External Wall Insulation
While EWI offers many benefits, it’s not without challenges:
1. High Upfront Cost
EWI is a significant investment, typically costing £8,000–£15,000 for an average UK home. However, long-term savings on energy bills can offset this.
2. Planning Permission Aesthetic Restrictions
If your home is listed or in a conservation area, you may need planning permission. Some local authorities restrict changes to historic properties.
3. Disruption During Installation
Scaffolding is required, and the process can take 2–4 weeks, depending on weather and property size.
4. Not Suitable for All Properties
Homes with intricate architectural details (e.g., ornate brickwork, bay windows) may require specialist solutions.
5. Potential for Poor Installation
If done incorrectly, EWI can trap moisture or lead to cracking. Always use certified installers with experience in older homes.
Is EWI Worth the Investment?
To determine if EWI is right for your older home, consider:
1. Your Home’s Construction
Solid walls? EWI is often the best solution.
Cavity walls? Cavity wall insulation may be cheaper.
Damp issues? Address these before installing EWI.
2. Long-Term Savings vs. Upfront Cost
While expensive, EWI can save £200–£500 annually on energy bills. Over 10–20 years, this adds up.
3. Available Grants Funding
UK: The Great British Insulation Scheme offers support.
Local councils sometimes provide grants for energy efficiency.
4. Alternative Options
If EWI isn’t feasible, consider:
Internal wall insulation (cheaper but reduces space).
Loft floor insulation (complementary measures).
Case Study: A Victorian Home with EWI
A Victorian terraced house in London had solid brick walls and high heating costs. After installing EWI:
Energy bills dropped by 30%.
Indoor temperatures stabilized.
Exterior looked refreshed with a modern render.
Property value increased by ~5%.
The initial £12,000 investment paid for itself in 10 years through energy savings.
Final Verdict: Should You Invest?
Yes, if:
✔ Your home has solid walls.
✔ You plan to stay long-term (10+ years).
✔ You want to improve energy efficiency comfort.
✔ You can access grants or financing.
No, if:
✖ Your home is listed or in a conservation area (without approval).
✖ You’re selling soon (ROI takes years).
✖ You have unresolved damp issues.
Conclusion
External wall insulation can be a game-changer for older homes, slashing energy bills, improving comfort, and protecting the building’s structure. While the upfront cost is high, the long-term benefits make it a worthwhile investment for many homeowners.
Before committing, consult a qualified insulation specialist, check for grants, and weigh the pros and cons based on your property’s needs. With the right approach, EWI can transform an old, draughty house into a warm, efficient, and modern home for decades to come.
