[Count'n the days]

I am considering what type of window treatments to purchase for our home. I know some provide more energy efficiency than others, but my preference is to be able to have blinds or shutters to be able to adjust the light in addition to providing privacy. Can anyone tell me if the windows in the new homes are very energy efficient? I'm sure they are not the best LowE windows, but assume much better than single pane windows. Are you able to leave your widow treatments open during the day and stay comfortable during the summer? Thanks for your help.