kathieb wrote:
which is better window? installer is quoting me same price for both at approximately $500 per window installed. Is that reasonable?

I paid more then that for the Imperial LS. Hope I didnt pay too much. Not that I am complaining, I love these windows, my thanks to all that recommended Soft Lite Imperial LS to me. After going over the installation with a fine tooth comb, and noting the LS air infiltration rating of .02, I wonder where even that tiny amount of air will come in through.
I also have 2 Garden windows I would like to replace. Could I replace them with Casements or Sliders? Please advise.
It depends on the size for casements. Generally they aren't made wider than 36". However you could put multiple casements together. Casements have much lower air infiltration rates than sliders but, sliders are usually less expensive.