Which statement best describes low-conductivity window frames?

• A. Frames made of metal
• B. Frames that conduct heat poorly or are insulated
• C. Frames with no insulation
• D. Frames that conduct heat well

Answer: (B)

Low conductivity means the frame resists heat flow. Frames that conduct heat poorly or are insulated fit this idea because they minimize heat transfer between indoors and outdoors, improving energy efficiency. Materials like vinyl, wood, or fiberglass typically have lower thermal conductivity than metal, and many frames include design features or insulation to further reduce heat transfer. Metal frames by themselves tend to conduct heat quickly, unless a thermal break or insulation is added to interrupt the path of heat flow, so they aren’t described as low-conductivity on their own. A frame with no insulation or one that conducts heat well would increase heat loss, not reduce it. So the best description is frames that conduct heat poorly or are insulated.