What initial temperature reading indicates a potential issue with indoor airflow in heat mode?

The initial temperature reading of 38°F in heat mode suggests a potential issue with indoor airflow because it falls within a range that might indicate insufficient heat transfer. In heat pump operation, especially in heat mode, the temperature measured at the supply vent or outlet should typically be significantly above the ambient indoor air temperature. A reading of 38°F could imply that the heat pump is not effectively distributing heat throughout the space, possibly due to problems such as blocked air filters, closed or obstructed vents, or issues within the fan or blower.

In contrast, higher reading temperatures like 41°F or 44°F would indicate that the system is generating and distributing heat effectively, whereas a considerably lower reading, like 35°F, might not provide enough context by itself. However, 38°F stands out as an indicator of a problem, as it suggests that the heat pump is neither adequately heating the space nor maintaining proper airflow, warranting further investigation.