Reducing energy consumption and CO2 emissions becomes more and more important. Not only because of climate change related issues, but also to realize our ambition to become energy independent. To increase the energy-efficiency in buildings, we developed a thermochromic coating for smart windows which is optimized for climates with seasonal changes. Here we present the first results of our smart window performing in real environment. We show that measured solar transmission and thermochromic performance is comparable to measurements in the lab. Furthermore, we present a further optimized thermochromic coating with record optical properties of Tvis = 70% and ΔTsol = 20.1%. Via a building energy simulation study using data from this high performing coating, we show that energy savings between 17-37% can be achieved in the Netherlands, depending on the building type. Furthermore we show that by the use of our new smart window annual energy cost savings between 266 – 553 EUR/a for a single household can be achieved. The thermochromic coating usually accounts for 60 – 70% of these cost savings equaling between 8 – 10 EUR/a per m2 glass. Due to the low material and processing costs for the thermochromic coating, an attractive return on invest with market conform profit margin is possible.

With constantly progressing climate change and global warming, we face the challenge to reduce our energy consumption and CO2 emission. To increase the energy-efficiency in buildings, we developed a thermochromic coating for smart windows which is optimized for intermediate climates. Here we present a building energy simulation study for the use of our smart window in the four main residential building types in the Netherlands. In the study we show that for all building types energy savings between 15-30% can be achieved. Hereby the impact of the windows on energy consumption is dependent on the window surface area as well as the total floor space. Furthermore we show that by the use of our new smart window, where the thermochromic coating is combined with a standard low-e coating, annual cost savings for energy between 220-445 € for a single household can be achieved. The thermochromic coating usually accounts for half of these cost savings, that is an addition in cost savings between 6-7.5 €/m2 glass. Due to the low material and processing costs for the thermochromic coating, a return on invest within 7 years should be feasible with these annual cost savings.

Building integrated photovoltaics (BIPV) offer aesthetics and freedom of design for architects and home owners. This can accelerate implementation and free up new spaces for solar energy harvesting at building level, which is a necessary step towards a climate neutral built environment. Colored solar panels with high conversion efficiency and low cost price are an important development for large scale market penetration of BIPV. Here we report a solution processed structural color coating for solar panels and solar collectors. We show that virtually any color can be prepared, that the desired coating stack can be designed using optical calculations and that the exact color can be produced via a low cost solution process. Furthermore, we show that the light transmission for the colored glass plates is still very high, exceeding commonly used absorbing colors and enables very high solar cell efficiency. The colored PV panels have been tested in real environment and via accelerated lifetime testing for 3 years without any performance decline or degradation.