Which of the following are potential signs of a malfunctioning heat pump?

Choosing unusual noises and inconsistent temperatures as potential signs of a malfunctioning heat pump is insightful because these factors directly indicate that the system is not operating effectively. A functioning heat pump should maintain a consistent temperature throughout the space while running quietly.

Unusual noises, such as grinding, hissing, or banging, suggest mechanical issues, such as loose or damaged components. Inconsistent temperatures could indicate a problem with airflow, refrigerant levels, or the heat pump's overall efficiency, potentially leading to inadequate heating or cooling and increased energy consumption.

The other options, while they may relate to the overall function or appearance of a heat pump, do not serve as immediate indicators of malfunction. Consistent temperatures and regular energy bills typically signify that the system is functioning correctly. Improper installation and aesthetic defects, while problematic, usually don’t reveal immediate operational failures but rather long-term efficiency issues. Lastly, infrequent maintenance and dust accumulation are maintenance-related concerns that, while detrimental over time, do not necessarily indicate the current operational status of the heat pump itself.