What effect does outdoor temperature have on heat pump performance?

The performance of heat pumps is significantly affected by outdoor temperature, and the correct choice indicates that efficiency typically decreases as temperature drops.

Heat pumps operate on the principle of transferring heat from outside to inside a building. As outdoor temperatures decrease, the amount of thermal energy available in the outside air diminishes, making it more challenging for the heat pump to extract sufficient heat. This leads to a drop in the heat pump's coefficient of performance (COP), which measures its efficiency. In colder conditions, the heat pump must work harder to maintain indoor comfort levels, resulting in increased energy consumption and decreased efficiency.

This relationship highlights the importance of considering outdoor temperatures when evaluating heat pump performance. While the actual mechanisms are complex, the fundamental understanding that lower temperatures lead to reduced efficiency is essential for effective heat pump operation and energy management in residential heating systems.