The extreme cold and fluctuating weather in Minnesota make energy efficient windows a must. Look for windows with Extruded Polystyrene foam-filled frames, multi-chamber profiles, triple-pane glass, and two low-E coatings to maximize efficiency. Wood, vinyl, or fiberglass frames insulate well. And make sure to choose metal reinforcements and laminated/insulated glass for impact resistance. Both Pella and Alliance offer window lines specifically built for cold Midwest climates like Minnesota.