Within the IEE SAVE project ASIEPI studies on the impact of thermal bridges on the energy performance of buildings have been collected. Most studies dealt with the influence on the heating energy use, which can be considerable if the building is a high performance building (with a low heating energy use). Then it makes as much sense to focus on good building component joint design and realisation as to include even more insulation or a system with even better efficiency.
We have found however only one study dealing with the thermal bridge impact in summer. The study on a Greek building found out that there is only a very small increase in the cooling energy, but a bigger influence on the cooling load which can be as high as 15 %. The cooling load of a calculation including the additional thermal losses (gains) of thermal bridges was compared to the same calculation without considering the thermal bridges.
This was discussed quite vividly during an European experts meeting this week with some South European experts stating that the influence is not as big.
What is your experience on that? Have you made any study on the impact of thermal bridges on the cooling energy and cooling load of a building?
French Studies on influence of thermal bridges on the energy performance
In first we studied effect on heating consumption. The increas of U value (global transmittance) is accompanied by an increasing of heating energy saved.
When we studied cooling, the effect was inverse. The increase of U value is accompanied by an increase of cooling consumption.
Through this study we conclude that if we are looking to have a comfortable building in winter and in summer, we must make an optimisation study.