How to build a cooling ceiling

Cooling is not air conditioning

An air conditioner produces cold and blows it. A chilled ceiling does the opposite: it absorbs the heat of the warm masses in the room by radiant exchange, with no air movement. You do not feel a cold draught, you feel the ambient heat gradually going away.

The cold pane principle

A surface held colder than the room takes in the infrared emitted by walls, floor, furniture and people. The body gives up its heat by evaporation and by radiation towards that surface. That mechanism, not an air flow, is what produces the sensation of coolness.

The limit not to cross

The ceiling must never drop below the dew point of the ambient air, or it condenses. The entire design of a chilled ceiling rests on that constraint, and it is what separates it from a simple chilled water loop in the ceiling.

The ventilation that goes with it

Air renewal takes place around the perimeter of the ceiling, along the walls, or through the fabric itself when it is micro-perforated. The air has no velocity, so no perceptible draught, and the noise of a supply grille disappears.

The case of houses over several floors

Since cold does not travel down from one floor to another on its own, each level gets its own exchange surface. That is what makes the same temperature possible everywhere, which a split unit in the living room will never do.

The system is described on the eClim, cooling and heating radiant ceiling page, and the evenness obtained on the page about even cooling.