My study catches a lot of sun in the summer. It's lovely in winter because it keeps the room quite warm but it was getting to be a problem in summer when the room was really hot and glarey which made it hard to focus on my computer monitor. In the end I did some research and found that by replacing my windows to a more glare proof style of glass I would be able to make the room a lot more comfortable. Now it's a really pleasant and easy to use study. This blog has tips on switching to glare minimising windows.