Which function does a central heating radiator primarily serve?

A central heating radiator primarily serves the function of distributing heat throughout a space. When hot water or steam circulates within the radiator, it emits heat into the surrounding air, which raises the overall temperature of the room. This process creates a comfortable living environment, especially during colder months.

Radiators are designed to maximize this heat transfer efficiency by having a large surface area to release heat and often being placed in strategic locations in a room to ensure even warmth. The design and material of the radiator also help in this function, allowing for optimal conductivity and heat dispersion.

By contrast, while cooling, air purification, and moisture absorption are helpful functions in certain contexts (like air conditioners or dehumidifiers), they do not pertain to the primary role of a central heating radiator. This focus on heat distribution clearly establishes why it is the correct option in this context.