Both the window frame and sash construction and the glass itself contribute to the window unit's energy-savings performance. Choosing a window with an insulating frame, good sash construction and a high performance glazing will help save energy and result in lower heating and cooling costs for your home. Start with a good frame and solid construction For good thermal performance, it's important to choose a well-constructed window made from a sturdy, insulating material. Wood and vinyl are the most common window frame materials, and both are excellent insulators. Although wood windows were once favored by homeowners because of their traditional place in house design, vinyl is now selected more often for replacement windows.
Homeowners choose vinyl because it's much easier to maintain than wood.
Simply washing vinyl windows with soap and water will leave them looking like new. Wood has kept a place in house design because it can be stained or painted, giving homeowners many choices for interior decoration. Its drawback is that it requires heavy maintenance. But now, a new technology offers homeowners the interior design flexibility of wood with the durability and easy maintenance of vinyl. A well-constructed window also will have features that ensure good insulation and protection against air and water infiltration.