In what condition can heat pumps potentially operate effectively?

Heat pumps can operate effectively at temperatures below -10 °F, especially if they are specifically designed for such conditions. Many modern heat pumps, particularly those labeled as cold-climate heat pumps, have advanced technology and features that allow them to extract heat from the outdoor air even in very low temperatures. This capability is crucial because it allows for efficient heating of spaces during winter months, reducing reliance on supplemental heating sources and providing energy-efficient heating solutions.

In contrast, the other options imply restrictive scenarios that do not accurately reflect the versatility of heat pump technology. For instance, heat pumps are not limited to operating only above 50 °F, as they can function effectively through a wider temperature range with proper design. They are also not restricted to high humidity climates, since they can operate in a variety of environmental conditions. Additionally, while heat pumps are widely used in residential applications, they are also installed in commercial and industrial settings, making them versatile beyond just residential use.