Natural Resources Canada ENERGY STAR certified ENERGY STAR® the Natural Resources Canada (NRCan) website English Natural Resources Canada outlines some key features skylight Energy-efficient windows Natural Resources Canada According to National Resources Canada Energy Star windows, doors and skylights Excellent Energy Star and NAFS-11 energy efficiency ENERGY STAR Most Efficient Energy Star Looking for Energy Efficient Windows? Natural Resources Canada Natural Resources Canada energy-efficient skylight Looking for Energy Efficient Windows? Looking for Energy Efficient Windows?