My low-e glass seemed just as bright as any other glass, but it blocked almost all of the UV rays, which seems to be more of a factor than anything. One thing I loved about those windows is that nothing in the house faded. Wish I could say the same for the windows in this house. My couch took a hit! But, I can grow tomatoes in the kitchen window now, so it evens out!
We'll eventually replace the windows in this house too, but I've decided that the kitchen window isn't going anywhere! I have lots of windows along the south side of the house, but the sills are really low, and the dogs are always looking outside, when they are inside. So, the only safe place is the kitchen. I wish I could line every window sill with seedlings before those windows get replaced!