I love to hear that nowadays most of the people who are building new homes are paving very importance for natural lighting and energy efficient windows and doors. Many opt for windows and door replacement also. You can check this. . For you,I can suggest that you must go for a perfect design of the windows. Winter seasons are as difficult as summer to be bearable.If you are looking for a window to maximize heat gain, it must have a U-factor of 0.35 or less. Also the air gap must be considered. Windows such as awning, casement, fixed and hopper are designed so that they can be closed tightly with little air escaping.
Thank you for reading me.