What energy-efficient features should your replacement windows have? According to the Efficient Windows Collaborative (http://www.efficientwindows.org), a group of insulation and window manufacturers that comply with federal energy requirements, new windows should have low-e coatings, which let in visible light but block radiant heat losses to cut heating bills.
The nonprofit Alliance to Save Energy (http://www.ase.org) in Washington, D.C., maintains that replacing windows adds value to a house in several ways. It improves the appearance and resale value of the home. It reduces maintenance costs such as painting and makes cleaning easier with tilt-sash designs.