U-values for EnergySaver
The Building Regulations target thermal performance requires that external walls achieve a minimum U-value of 0.27 W/m2K. it may not be physically possible to achieve the target U-value with an existing cavity wall, due to the width of the “as built” existing cavity. However, any improvement upon the buildings thermal performance will assist in reducing your heating bills and CO2 emissions.
The table below shows the thermal improvements of an un-insulated cavity wall when filled with Rockwool HP Energy Saver.
Typical U-value of an uninsulated cavity wall = 1.70 W/m2K
| HP EnergySaver Thickness/ cavity width | U-value (W/m2k) |
| 50mm | 0.58 |
| 65mm | 0.48 |
| 75mm | 0.43 |
| 100mm | 0.34 |
| HP Energysaver has a thermal conductivity of 0.040 W/mK | |
| The contractor will be required to state the U-value achieved on their submission to SEI on completion of work |
