Internal insulation system for solid walls
Cost savings and reduction in carbon emissions
Reduction in carbon emissions
Carbon emission savings in representative properties:
| Property type | Bedrooms | Emission savings (kg CO2e p.a.) | |
|---|---|---|---|
| Gas | Electricity | ||
| End terrace house | 2 | 626 | 1806 |
| Semi-detached house | 3 | 530 | 1530 |
| Detached house | 4 | 1903 | 5493 |
| Fuel | Factor |
|---|---|
| Electricity | 0.58982 |
| Gas | 0.20435 |
Cost savings
Based on typical UK energy usage patterns and recent cost data (as of 2025-2026), insulating a house to provide a ~39% improvement in thermal U-value (a common outcome for solid wall or improved cavity insulation) can lead to annual savings of roughly £300 to over £800, depending on the property size.
Below are estimated annual gas and electricity costs (dual fuel) for 2025/2026, assuming uninsulated vs. improved insulation (approx. 30-40% savings on heating, which is generally 60-70% of a bill).
Estimated Annual Energy Bills (Gas & Electricity)
| House Type | Uninsulated Annual Bill | With 12mm Ultrotherm | Estimated Annual Saving |
|---|---|---|---|
| 2-Bed End Terrace | £1,700 – £2,000 | £1,150 – £1,350 | ~£550-£650 |
| 3-Bed Semi-Detached | £2,200-£2,600 | £1,500-£1,800 | ~£700-£800 |
| 4-Bed Detached | £2,800 – £3,500+ | £1,900 – £2,400 | ~£900-£1,100+ |
Note: These figures are estimates based on standard, non-electric heating, and 2-3 occupants, with energy prices around the 2025-2026 Ofgem price cap levels.
Savings when using Ultrotherm
- Impact of U-Value Improvement: A 39% improvement in U-value implies a significant reduction in thermal transmittance (heat loss). While wall insulation reduces heat loss by up to 40%, overall household energy bill savings are typically in the range of 15% to 35% for the whole house (as some heat is lost through roofs and windows).
- Solid vs. Cavity Walls: The largest savings are often realised in older, uninsulated solid wall properties (common in pre-1930s homes) where 35% of heat is lost through walls.
- Highest Savings: 4-bed detached houses have the highest potential for savings because they have the largest surface area for heat loss.
- Secondary Benefits: Improved insulation not only cuts bills but also raises EPC ratings and increases property value by 2-6%.