Which of the following components is NOT typically found in a high-efficiency furnace?

High-efficiency furnaces are designed to maximize energy efficiency and typically use advanced technology to achieve this. One of the key features of high-efficiency furnaces is the presence of a secondary heat exchanger. This component captures additional heat from the flue gases after they have passed through the primary heat exchanger, allowing for more heat to be transferred into the home before the gases are vented outside.

In contrast, a single heat exchanger is not characteristic of high-efficiency models, which usually utilize two heat exchangers to facilitate this extra heat extraction and reduce wasted energy. Thus, the absence of a single heat exchanger aligns with the design philosophy of maximizing efficiency.

DIP switches are often included for configuration and adjustments but are not a defining component of furnace efficiency. Similarly, a combustion blower is necessary in both standard and high-efficiency furnaces to facilitate proper combustion and venting. Therefore, the identification of a single heat exchanger as the component not typically found in a high-efficiency furnace correctly reflects the technology that distinguishes these systems from standard models.