How does demand defrost differ from timed defrost?

Demand defrost functions by activating only when it is necessary based on specific conditions, such as the accumulation of frost on the evaporator coil. This method is designed to enhance system efficiency by ensuring that defrost cycles are initiated only when needed, rather than at regular intervals regardless of frost build-up. This helps to maintain higher operational efficiency, reduces unnecessary energy consumption, and minimizes the disruption of heating.

In contrast, timed defrost operates on a pre-set schedule, triggering defrost cycles at regular intervals without considering the actual frost conditions. This can lead to unnecessary defrost periods and potential energy waste if there is not enough frost present to warrant a defrost cycle.