The demand for energy savings in buildings will increase in the coming years, as the world’s attention is drawn towards environmental aspects and energy economizing. Windows which are able to dynamically control the sun radiation through-put will play an important role. In this respect we have studied two different electrochromic window configurations; one based on the two complementary electrochromic materials polyaniline (PANI) and tungsten oxide (WO3), the other one with the electrochromic coating Prussian blue (PB) in addition to PANI and WO3. The inclusion of PB enhances the transmission modulation. Integrating over the solar spectrum we find that the window based on PANI and WO3 is able to regulate 39% of the total solar energy, while with the inclusion of PB we manage to regulate as much as 50% of the sun radiation.