External Wall Insulation
Wrap your home in warmth and slash energy bills
About External Wall Insulation
External wall insulation (EWI) is one of the most effective ways to reduce heat loss from solid-walled properties common across East Anglia. Many Victorian and Edwardian homes in Cambridge, Bury St Edmunds, and Norwich have solid brick walls with no cavity, losing up to 35% of heat through their walls. By wrapping your home in insulation and protective render, we can cut that heat loss by up to 70% and improve your EPC rating by two or more bands.
Key Benefits
Heat Pump Costs (After BUS Grant)
Insulation is the essential first step before installing a heat pump. These heat pump costs show the savings you unlock once your walls are insulated.
| Property | Heat Pump Size | HP Net Cost | Annual Running |
|---|---|---|---|
| 1-2 bed | 5-6 kW | £0 - £2,500 | £610 - £720 |
| 3-bed semi | 8-10 kW | £500 - £5,500 | £610 - £720 |
| 4-bed detached | 10-12 kW | £3,500 - £10,500 | £610 - £720 |
Helpful Guides
Our Installation Process
Property Assessment
We survey your property, assess wall construction, check for damp issues, and measure all elevations for accurate quoting.
System Selection
We recommend the optimal insulation thickness and render finish based on your wall type, budget, and aesthetic preferences.
Installation
Scaffolding is erected and insulation boards are mechanically fixed and adhesive-bonded to external walls, followed by mesh reinforcement and render application.
Finishing
Final render coat is applied in your chosen colour and texture. We remove scaffolding, clean up, and update your EPC certificate.
Typical Timeline
Works Well With
Insulate first, then install a smaller, cheaper heat pump. The correct order saves thousands.
Airtight insulated homes need mechanical ventilation to maintain fresh air quality.
Insulation reduces total energy demand, meaning solar can cover a larger share of your bills.
Financing
EWI costs £90-£150/m². Mid-terrace £6,000-£10,000; semi £8,000-£15,000; detached £18,000-£30,000. ECO4 may cover full cost (ending 31 Dec 2026). Warm Homes Local Grant (up to £15,000) from 2027. U-value improves from 2.1 to 0.29 W/m²K (86% improvement).
Warranty
- 25-year system warranty
- 10-year workmanship guarantee
- BBA certified EPS, mineral wool, or phenolic systems
- Range of render finishes available
Popular Combinations
Combine services for greater savings. All figures based on typical East Anglia households.
Insulation + Heat Pump
Insulate first, then a smaller heat pump works harder for less. The correct upgrade order.
Insulation + Heat Pump + MVHR
The complete fabric-first retrofit. Airtight, insulated, ventilated, and efficiently heated.
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Frequently Asked Questions
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