I bought a TEQOYA TIP9 ioniser because I sleep well only when the window is open, with the feeling of fresh air circulating. But it isn’t always possible in winter time or when it’s noisy outside. When I’m working, I also need to get out regularly to get some fresh air. After I plugged in my TEQOYA ioniser in our bedroom, I quickly felt that the air around me was fresher, cooler and more invigorating. I sleep much better even with closed windows. And this in a large,35m2 surface-area bedroom! My wife was rather skeptical, but after a few weeks she acknowledged feeling the same. It definitively strengthened my thought that I had made a good purchase!