External Wall Insulation in Harrow. For many homeowners with traditional properties, heat loss does not happen evenly. Often, specific architectural features – such as bay windows or thin wall panels – act as massive thermal bridges, allowing expensive central heating to escape rapidly.
For this recent project in Harrow, the goal was to address these specific, highly vulnerable areas. By applying a targeted External Wall Insulation (EWI) system to the sections surrounding the windows, we were able to significantly boost the energy efficiency of the room without needing to render the entire brick facade.

Stopping Localised Heat Escape
The panels below and above windows are notorious for being thin and poorly insulated, pulling the cold in from the outside.
To solve this targeted heat loss, our team applied thick 90mm EPS (Expanded Polystyrene) boards directly to the vulnerable sections. This premium insulation layer immediately cuts off the thermal bridge in these specific zones. Instead of escaping through the thin panels, the warmth is now reflected back into the living space, eliminating cold draughts near the window.
To seamlessly blend this new, highly efficient layer with the existing property, we finished the panels with a premium 1.5mm Silicone Render. The smooth, modern grey finish provides a crisp, contemporary contrast to the traditional brickwork. Furthermore, the silicone is inherently breathable and highly water-resistant, protecting these previously vulnerable sections from dampness and harsh weather.
Project Specifications
Here is the technical breakdown of the system we used to upgrade these specific wall panels in Harrow:
| Feature | Specification | Why it matters |
| Location | Harrow, Greater London | Upgrading targeted heat retention in traditional properties. |
| System | Targeted External Wall Insulation | Eliminates specific thermal bridges around windows. |
| Insulation | 90mm EPS Boards | Delivers a massive boost to localised energy efficiency. |
| Finish | 1.5mm Silicone Render | Highly durable, weather-resistant, and visually sharp. |
Why London Homeowners Trust EWI Specialist Ltd
Whether we are insulating an entire property or performing a targeted upgrade, every project is executed to the highest industry standards. Our work on this Harrow property complies with strict PAS2030 government standards, ensuring the retrofit performs exactly as promised.
Furthermore, every installation is protected by our ironclad Triple Guarantee:
- System Guarantee: Full technical backing on the longevity of the materials used.
- Workmanship Guarantee: Our personal, uncompromising promise of installation precision.
- Insured Guarantee: Total third-party financial peace of mind.

Ready to eliminate cold spots in your home?
If you have specific rooms that are always cold, or want to upgrade the thermal performance of your window panels without rendering your entire house, our expert team is here to help.
[Get Your Free, No-Obligation Quote] – Let our experts design your bespoke EWI system today.
[Contact EWI Specialist Direct] – Have technical questions about heat loss? We are always happy to advise.


