In a conventional gas furnace, the hot flue gases are ____.

• A. used to heat water in a separate tank
• B. recycled back into the furnace for additional heating
• C. filtered and released into the room
• D. vented directly to the outside

Answer: (D)

Verified step by step guidance

1. Understand the role of flue gases in a conventional gas furnace: Flue gases are the combustion products formed when fuel burns inside the furnace.
2. Recognize that flue gases contain harmful substances such as carbon monoxide and other pollutants, which makes it unsafe to release them directly into the living space.
3. Recall that conventional gas furnaces are designed to safely remove these flue gases from the home to prevent health hazards.
4. Identify that the standard and safe practice is to vent these hot flue gases directly to the outside environment through a chimney or vent pipe.
5. Conclude that the correct answer is that the hot flue gases are vented directly to the outside, ensuring safe operation of the furnace.