Keeping the cold air from coming in through your windows is tricky. Since you cannot insulate a window like you can a wall, you have to increase the R-value in other ways. Window technology has improved over the years, becoming more and more efficient. Window manufacturers now are creating new ways to improve energy efficiency by creating coating on the glass and adding multiple glass panes in each window. Most new houses use double panes in their construction where the more efficient soulution is the triple pane windows. Insulation is only the benefit of better windows, they can also block out the sound more. Thus your home can feel more like a home.