Duct furnaces should be installed on which side of the circulating air blower?

Duct furnaces are designed to heat air that is then circulated throughout a space by a blower. Installing the duct furnace on the positive pressure side of the circulating air blower is essential for several reasons.

Firstly, when a duct furnace is placed on the positive pressure side, it allows the heated air to be forced through the ducts and into the desired rooms. This setup ensures that the furnace can efficiently deliver warm air without the risk of drawing in unconditioned cold air, which could undermine the heating process.

Additionally, placing the furnace on the positive pressure side helps prevent the potential for combustion gases to leak into the living space, ensuring that safety standards are met. A positive pressure installation reduces the risk of backdrafts, where the heated air in the system could cause exhaust gases to flow back into the ductwork.

The alternative options, such as the negative pressure side or neutral pressure side, would not provide the same level of efficiency or safety. On the negative pressure side, the system could potentially pull in air from undesirable sources, and on the neutral pressure side, neither heating nor optimal airflow characteristics would be effectively achieved.

Thus, the installation of a duct furnace on the positive pressure side of the blower is critical for efficient heating and maintaining a safe