Phase change materials (PCM) have received considerable attention over the last decade for use in latent heat thermal storage (LHTS) systems. PCMs give the ability to store passive solar and other heat gains as latent heat within a specific temperature range, leading to a reduction of energy usage, an increase in thermal comfort by smoothing out temperature fluctuations throughout the day and a reduction and/or shift in peak loads. The interest around PCMs has been growing significantly over the last decade. Hence, several commercial products have arrived on the market with various areas of use in building applications. This study reviews commercial state-of-the-art products found on the market and show some of the potential areas of use for PCMs in building applications. Examples of how PCMs can be integrated into buildings, and furthermore building materials and projects using PCMs that have already been realised, have also been reviewed. There seems to be a scarcity of data published on actual performance in real life applications so far. However, many laboratory and full scale experiments have shown positive results on energy savings. Furthermore, future research opportunities have been explored and challenges with the technology as of today have been discussed.

Low-emissivity (low-e) materials can be used in order to reduce energy usage in both opaque and transparent areas of a building. The main focus for low-e materials is to reduce the heat transfer through thermal radiation. Furthermore, low-e materials will also influence on the daylight and total solar radiation energy throughput in windows, the latter one often characterized as the solar heat gain coefficient (SHGC). This work reviews low-e materials and products found on the market, and their possible implementations and benefits when used in buildings. The SHGC is often left out by many countries in energy labellings of windows. With opaque materials, research is still ongoing to correctly calculate the effect with regard to thermal performance when applied in buildings. Future research perspectives on where low-e technologies may develop are explored. To the authors' knowledge, there seems to be little available literature on how ageing affects low-e materials and products. As this is of large significance when calculating energy usage over the lifetime of a building, ageing effects of low-e materials should be addressed by manufacturers and the scientific community.

Vacuum insulation panels (VIP) are regarded as one of the most upcoming high performance thermal insulation solutions. At delivery, thermal conductivity for a VIP can be as low as 0.002-0.004 W/(mK) depending on the core material. VIPs enable highly insulated solutions, and a measure to reduce the energy usage in both hot-water applications, cold applications and for the construction industry in general. This study gives a state-of-the-art review of VIP products found available on the market today, and explore the future research opportunities for these products.VIPs have been utilized with success for applications such as freezers and thermal packaging, and during the last decade they have also been used for building applications in increasing numbers, where one of the main driving forces is the increased focus on e.g. passive houses, zero energy buildings and zero emission buildings. Hence, VIPs are now in the early market stages as a building product. Implementation of VIPs in various building constructions have given an increased interest in the possibilities of this product, both in new and refurbished constructions. Even though there is not enough data to conclude the effect over a lifetime of a building yet, the immediate result in decreased energy usage can be seen. However, the problem of guaranteeing a set lifetime expectancy, along with high costs, are some of the major reasons why VIPs are met with scepticism in the building industry. Aiming to give better quality assurance for the users, make further advances in envelope technologies and the development of core materials, along with a further cost reduction is crucial for VIPs to become a competing thermal insulation solution for buildings.

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