Energy Savings for a Wood Based Modular Pre-fabricated Façade Refurbishment System Compared to Other Measures

There is a need to focus on energy efficiency for the existing buildings, especially buildings erected before the energy crises in the seventies, as these buildings provide a massive potential for improvements in energy performance. The facades of these buildings are also facing an increased need for a face-lift. There are a large number of such facades in all these countries. One problem is that these buildings must be refurbished at low costs and with limited disturbance to the users/tenants. In this study we have investigated the energy efficiency of a modular pre-fabricated façade refurbishment system based on wood and compared it to two existing systems for on-site mounting of additional insulation. These existing alternatives require a lot of on-site works. Hence pre-fabricated solutions would, of course, offer advantages. There have been several attempts to develop such solutions in recent years but so far none of them have provided an acceptable solution. This approach is based on an alternative with small scale prefab elements with a simple assembly process. The energy analyses concentrate on thermal bridges and U-values, relating it to the total energy performance and compared to the current situation and comparable refurbishment methods. We have mainly focused on the wall structures but as a comparison also other energy saving measures has been investigated shortly. For the very common reference building the pre-fabricated solution is the third most effective energy measure. We have also conducted a study of the energy efficiency regulations in different Nordic countries in order to see what the current legal framework is, and tried to sort out how far it is possible to improve energy efficiency by means of improving the U-value of the exterior walls. The outcome is a verification of the energy efficiency of the chosen prefab structure as a solution for refurbishment. The advantages are to be found in the dry production process combined with a simple and fast assembly on site. Similarly, there are advantages in the reduced number of thermal bridges and in the potential for the use of recyclable materials. Another advantage is that it has an integrated air tightness that is mounted on the outside of the existing wall. This is part of a larger research project aiming at cost efficient and sustainable solutions for refurbishment of facades in a Nordic context. In the larger research project, we have also conducted a cost-benefit analyses and studie