Storm windows can reduce your heat loss through the windows by 25% to 50%. Storm windows should have weatherstripping at all moveable joints; be made of strong, durable materials; and have interlocking or overlapping joints. Low-e storm windows save even more energy.
When undertaking an attic or third floor renovation, consider using a crane for the heavy materials. For about $500 a day you can rent a small crane or lift. It can easily handle heavy materials like lumber and drywall, not to mention hot tubs. They can boom out about 42 feet, enough to get to the top floor of most homes.