Properly installed energy-efficient windows make homes more comfortable by reducing drafts and increasing the temperature of the interior side of the window, reducing condensation. Energy-efficient windows will have many of the following features:

• double-, triple- or even quadruple-glazing
• low-emissivity (low-E) glass
• inert gas, such argon or krypton in the sealed unit
• low conductivity or warm-edge spacer bars
• insulated frames and sashes
• good air tightness

If your inspection has revealed serious problems with a window's glazing, sash or the entire unit, your best option will be to replace all or part of the window.

For example, if the glazing is only a single pane of glass or is in poor condition, you can buy a new sealed glazing window insert. If the frame is in poor condition, it may be time to replace the unit.