You know that lively Sixties’ song by the Hollies: “Look through any window, yeah, what do you see?” Well, if all you can see when you look out your window is dirt and grime, that’s a problem. And if ...

On the rare occasions when the weather is truly perfect, you probably enjoy opening your windows to let in some fresh air. On every other day, when they’re closed, you have no choice but to stare at ...