True or False: A gas furnace back-up system typically has the heat exchanger located upstream of the heat pump coil.

A gas furnace back-up system indeed typically has the heat exchanger located upstream of the heat pump coil. This configuration is common because it allows the gas furnace to preheat the air before it passes through the heat pump coil. When the outdoor temperatures are too low for the heat pump to operate efficiently, the gas furnace can provide supplemental heating, ensuring that the air delivered to the living space is warm enough.

By positioning the heat exchanger upstream of the heat pump coil, the system can maximize efficiency and maintain a better temperature balance. This arrangement also benefits from the fact that the gas furnace can effectively heat the air during periods of high demand, supporting the overall performance of the heat pump in colder weather. This design is particularly advantageous in climates where both heating sources might be required at different times within the same season.