Which characteristic is less desirable in insulation materials for effectiveness?

High thermal conductivity is indeed a less desirable characteristic for insulation materials aimed at effectiveness. Insulation is intended to reduce the transfer of heat, keeping spaces warm in winter and cool in summer. Therefore, materials that exhibit high thermal conductivity allow heat to pass through more readily, diminishing their insulating capacity. Effective insulation materials should ideally have low thermal conductivity to enhance their performance in reducing energy loss.

The other characteristics mentioned are generally more favorable for insulation. Low dielectric strength is undesirable because it indicates that the material may not withstand high voltages, leading to electrical failures. Durability against physical damage is critical as insulation materials often need to endure wear and tear, ensuring longevity and maintenance of their insulating properties. Low moisture absorption is also favorable since moisture can significantly impact insulation performance, leading to reduced effectiveness and potential degradation of the material.