For most Naperville homes, double-hung windows fit traditional bedrooms and second-floor openings, casement windows create a tighter seal and strong ventilation, sliding windows fit wider horizontal openings, picture windows maximize light, and bay or bow windows work as feature windows in larger rooms.
The window type is only the first decision. Material, glass package, frame condition, room exposure, and installation method decide how well the final system performs in Chicagoland weather.