Why does soot reduce the efficiency of heating appliances?

Soot reduces the efficiency of heating appliances primarily because it reduces heat transfer. When soot accumulates on the heat-exchange surfaces, it creates an insulating layer that hinders the flow of heat from the combustion gases to the water or air being heated. The presence of soot means that less heat is effectively transferred to the intended medium, leading to lower efficiency in heating.

In heating systems, optimal performance hinges on maximizing heat transfer; when soot interferes with this process, the appliance has to work harder to achieve the desired temperature, ultimately leading to increased operational costs and potential damage over time. This condition can also prolong the time required to heat the space effectively, which is another factor that further diminishes overall efficiency.

While other factors like blockage, fuel consumption, and corrosion do play roles in the performance of heating appliances, the immediate and significant impact of soot accumulation is its direct effect on the heat transfer process.