Where should combustion air openings be located for a water heater installed in a confined space?

For a water heater installed in a confined space, the correct placement of combustion air openings is crucial for proper ventilation and to ensure safe operation. The recommendation to have two openings, one within 12 inches of the top and another within 12 inches of the bottom of the confined space, is based on the principle of air movement.

Having openings at these locations allows for a continuous flow of air, which is essential for combustion. The opening near the top helps to vent out the warmer air that naturally rises, while the opening near the bottom allows fresh air to enter. This setup aids in maintaining the air balance within the confined space, ensuring there is sufficient oxygen available for the combustion process. It also helps prevent the build-up of harmful combustion gases, thereby enhancing safety.

Additionally, placing the openings within 12 inches of both the top and bottom ensures that they are accessible and effective without hindering the overall design and functionality of the space. This configuration adheres to common building codes and best practices for safe water heater installation.