What is the term for the temperature at which the cost of heat energy supplied by the heat pump equals that of the backup fuel source?

The term that describes the temperature at which the cost of heat energy supplied by the heat pump equals that of the backup fuel source is known as the economic balance point. This concept is crucial as it helps homeowners and energy professionals determine when it is more cost-effective to utilize the heat pump for heating versus relying on an auxiliary heating source, such as a gas furnace or electric resistance heater.

At temperatures above the economic balance point, the heat pump operates effectively and is more economical compared to the backup source, while at temperatures below this point, the backup system becomes the more cost-effective option. Understanding this point allows for better energy management and potential cost savings in residential heating applications.

The other options do not accurately represent this specific intersection of cost effectiveness concerning the temperature threshold between heat pump operation and backup sources.