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Vacuum insulation panels (VIPs) represent a high performance thermal insulation material solution offering an alternative to thick wall sections and large amounts of traditional insulation in modern buildings. Thermal performance over time is one of the most important properties of VIPs to be addressed, and thus the ageing effects on the thermal properties have been explored in this work.Laboratory studies of ageing effects are conducted over a relatively limited time frame. To be able to effectively evaluate ageing effects on thermal conductivity, accelerated ageing experiments are necessary. As of today, no complete standardized methods for accelerated ageing of VIPs exist. By studying the theoretical relationships between VIP properties and external environmental exposures, various possible factors for accelerated ageing are proposed. The factors that are found theoretically to contribute most to ageing of VIPs are elevated temperature, moisture and pressure. By varying these factors it is assumed that a substantial accelerated ageing of VIPs can be achieved.Four different accelerated ageing experiments have been performed to study whether the theoretical relationship may be replicated in practice. To evaluate the thermal performance of VIPs, thermal conductivity measurements have been applied.The different experiments gave a varying degree of ageing effects. Generally the changes in thermal performance were small. Results indicated that the acceleration effect was within what could be expected from theoretical relationships, but any definite conclusion is difficult to draw due to the small changes. Some physical changes were observed on the VIPs, i.e. swelling and curving. This might be an effect of the severe conditions experienced by the VIPs during testing, and too much emphasis on these should be avoided.

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