SMARTLAB partners Carrig Conservation International are experts in heritage buildings, and their team will be carrying out a number of u-value measurements on participating heritage buildings.

U-value is a measurement of the thermal insulation properties of a building element, eg. a wall.

The BER standard U-values given for solid walls of historic construction does not always reflect their real performance. An in-situ U-value test allows the actual U-value of the wall to be tested and calculated.

In-situ U-value testing is non-invasive: two small sensors are taped to an internal wall at about head height and a third small sensor is taped to the exterior of the wall at the same point and connected to the others by a slim wire. The sensors measure the indoor and outdoor temperatures and the heat flux through the wall.

The sensors have to be located so that they are not too close to any nearby windows or cross-walls etc. The sensors need to be set up and then left in place for a minimum of 72hrs (3 days); 6-7 days is recommended to get the data required. The temperature difference between inside and outside must be at least 5 degrees Celsius over the duration of the monitoring period. Dry-lining and cavity walls present a barrier to getting accurate in-situ U-values, so if your building has either of these, please flag this with the team.

`Figure 1: Heat flux sensor and internal temperature sensor
Figure 2: External temperature sensor

If you have further questions or would like to discuss installing a u-value monitor through the SMARTLAB project, please contact us (here).