Where is an outdoor ambient thermostat typically set?

The outdoor ambient thermostat is typically set slightly above the initial balance point to enhance the efficiency of heat pump operation. The initial balance point refers to the outdoor temperature at which the heat pump alone can meet the heating demands of the space without needing auxiliary heating. By positioning the thermostat slightly above this point, the heat pump can effectively operate in temperatures where it is still capable of providing sufficient heating.

This placement helps prevent the unnecessary activation of supplementary heating, which can decrease overall system efficiency and increase operating costs. It allows the heat pump to function optimally for a longer duration, ensuring that it can handle moderate cold conditions effectively while avoiding excessive cycling, which can lead to wear and tear on the system.

In contrast, settings at freezing point or lower than the initial balance point may lead to reliance on auxiliary heating, and a cooling load point setting is not relevant for heating applications, which is the primary purpose of the outdoor thermostat in this context.