Ceiling Heating/Cooling System

What is a ceiling heating and cooling system?

A ceiling heating and cooling system is a water-filled radiant surface in the ceiling. It heats a room with warm water and cools it with cool water. Heat moves mainly by radiation between the ceiling surface and the people, walls and furniture in the room. In Slovak practice the name is stropné vykurovanie a chladenie. One water circuit serves both seasons, so the same surface works in winter and in summer.

There are two main ways to build it. The first is a capillary mat, a mat of thin tubes just under the ceiling surface. The second is a prefabricated panel hung below the ceiling structure. The two follow different standards, which the section on standards explains below.

How does a ceiling surface heat and cool a room?

Clina, a German maker of capillary mat ceilings, describes the principle on its product page. Warm or cold water flows through very thin capillary tubes with an outer diameter of 3.4 or 4.3 mm. The tubes sit under the surface of the room enclosing surfaces, and heat transfer is mostly radiant with a small convective part.

In heating mode the warm ceiling sends heat down to everything below it. In cooling mode the surface is cooler than the room, so it absorbs heat from the surfaces and the people. The room needs no fan for this, so the operation is quiet and draught-free. These statements come from the same manufacturer page, so treat them as the maker's description and not as independent test results.

What water and surface temperatures does it use?

The same Clina page gives typical values for its capillary mat ceilings. They show that the system runs at moderate temperatures in both modes.

These are manufacturer figures for one product family. The output of another system depends on its construction, so ask the supplier for the test data of the exact product.

How do you prevent condensation when the ceiling cools?

A cooled surface carries a risk of condensation, because water forms on a surface that is colder than the dew point of the room air. Clina calls this risk manageable and describes two measures. Each control zone has dew point sensors. If a risk appears, the control valve closes and stops the flow of water through the mats. The page also states that ventilation keeps the relative humidity at about 50 %.

This means the controls and the ventilation are part of the cooling system, not an optional extra. A ceiling that cools without humidity control can run wet. The sensing and the valve logic should be written into the design from the start.

Which standards apply, EN 14037 or EN 1264?

The two series cover different constructions. The scope of STN EN 1264-1:2021 states the split. The Slovak standards office published that edition in August 2021. The EN 1264 series covers water based heating and cooling systems embedded in the enclosure surfaces of the room. These systems are joined to the structural base of the surface. The same scope excludes ceiling systems in a suspended ceiling, where a designed open air gap separates the system from the building structure. For those, the EN 14037 series and EN 14240 give the thermal output.

The Slovak standards catalogue lists two parts of the EN 14037 series that are valid:

• STN EN 14037-1, released 1 January 2017: pre-fabricated ceiling mounted radiant panels for space heating.
• STN EN 14037-4, released 1 January 2017: pre-fabricated ceiling mounted radiant panels, test method for cooling capacity.

A capillary mat embedded in the ceiling belongs to the embedded systems of EN 1264. A free hanging panel belongs to EN 14037. When you compare offers, ask which series the quoted output refers to.

How does a ceiling compare with wall and floor emitters?

Clina states a typical capacity for each surface on its page. The floor figure is cited there according to DIN, and the other figures carry no standard. The numbers below are the maker's and are given only to show the order of magnitude. See also radiant floor heating, the wall heating system and the wider principle in radiant cooling.

A chilled ceiling is the name for the same surface when it is used for cooling only.

Why does a ceiling system suit a house with a heat pump?

The UK Passivhaus Trust explains in its guide How to build a Passivhaus that with a heat pump the heating system temperature is critical to performance. Energy use is roughly proportional to the difference between the outside and the heating system temperature, so low temperature systems are better. A ceiling that heats with water at 28 to 35 °C, as Clina states, is a low temperature emitter in that sense. The same circuit can then supply cool water in summer.