For the construction sector, energy efficient refurbishment is absolutely crucial in reaching the EU 2050 goals considering the fact that about half of the existing building stock in 2012 will still be operational in 2050 and approximately 85% of the dwellings was built before 1990 with poor insulation (R ~ 1.6 m2K/W). Ensuring a high quality indoor comfort is largely responsible for the energy consumption of buildings, on which the envelope, separating indoor from outdoor, has a major impact. Therefore the focus of refurbishment should lie on using the envelope (façade and roofing) to improve indoor environment at reduced energy consumption. Current retrofitting solutions to upgrade the envelope are mainly aimed at drastically increasing the insulation (R values > 3 m2K/W). Unfortunately, this requires thick insulation packages, airtight construction and consequently, additional ventilation and heat recovery systems to keep indoor comfort and air quality at the desired levels. As a result, housing corporations and owners are faced with time consuming and expensive refurbishment related to complex installations, while end users experience discomfort related to reduced space, over-heating and poor ventilation and may still have high energy bills related to additional ventilation and heat recovery systems. As a consequence, full replacement of facades is not often considered in refurbishments. A major market potential therefore exists for construction companies and building material producers if they obtain a cost-efficient, easy and quick to install solution for building envelopes, keeping thickness and additional ventilation installations to an absolute minimum while achieving optimal indoor comfort at significant reduced energy consumption.