Determining the most energy-efficient window involves considering various factors such as frame material, glazing options, and insulation features. Generally, triple-pane windows with low-emissivity (Low-E) coatings and insulating gas fills, such as argon or krypton, are considered highly energy-efficient. These windows provide better insulation against heat transfer and outside elements, resulting in reduced energy consumption for heating and cooling. Additionally, frames made from materials like fiberglass, vinyl, or wood-clad fiberglass offer excellent thermal performance, minimizing heat loss or gain through the window frame. Combined with proper installation techniques to prevent air leakage, triple-pane windows with advanced glazing and insulated frames stand out as some of the most energy-efficient options available in the market. However, it's essential to consider your specific climate, budget, and aesthetic preferences when selecting the most suitable energy-efficient window for your home. Consulting with a window specialist can help you navigate the available options and make an informed decision based on your needs and priorities.