You have the perfect underfloor heating for winter. What if, in summer, instead of sending hot water, you set the Heat Pump to send chilled water through the pipes? The floor would cool the entire home in complete silence, without the annoying draughts of conventional air conditioning!
It sounds magical, but nature has a strict rule. If you push it too far, your living room will turn into a water-soaked ice rink. Underfloor cooling absorbs your body heat and the heat from the walls (via radiation), creating the sensation of a cool cave in the height of summer.
Take a cold bottle of water from the fridge and leave it on the table on a hot summer day. Within 2 minutes, the outside of the bottle will be covered in water droplets (it will "sweat"). The bottle is not leaking - what happened is called Condensation.
The warm air (full of water vapour) touches the freezing surface and cools abruptly. Cold air cannot hold as much moisture, so it "drops" it on the surface as liquid water. The exact temperature at which this liquefaction starts is called the Dew Point.
If we send 7°C water to the underfloor system (as conventional air conditioners do), the floor will freeze. The humid room air will touch the floor and the tiles will "sweat" exactly like the bottle.
The tiles will become dangerously slippery - a fall hazard especially for elderly people and children. An uncontrolled puddle of water forms across the floor, damaging everything.
Wooden floors (laminate or engineered wood) will absorb the water, swell and be destroyed completely. Repair requires full removal and replacement of the entire floor.
To achieve cooling without "sweating", the engineer never allows the water to become excessively cold. In a cooling system, the water entering the floor is strictly regulated (via a three-way mixing valve) at around 18°C to 20°C. Never lower!
In each room, a specialised thermostat with a built-in hygrometer is installed. This brain continuously measures the temperature and humidity of the air and calculates the Dew Point in real time.
If the humidity in the room rises dangerously (e.g. you opened the patio door or are boiling pasta), the thermostat commands the three-way valve to slightly warm the water (from 18°C to 21°C) to keep the floor safe.
The three-way valve works like a "mixer" of hot and cold water. Depending on the thermostat's command, it blends warm water into the chilled water to keep the temperature above the Dew Point.
If the thermostat raises the floor temperature to 22°C to prevent sweating, the home stops cooling effectively! You will feel warm. That is why we need Solution No.2.
To solve the problem at its root, we must dry the air. If we lower the room humidity (e.g. from 70% to 45%), the Dew Point drops dramatically. The floor can then safely operate at 16°C and cool you properly!
Do NOT use ordinary portable dehumidifiers on wheels. They emit heat as they operate, completely cancelling out the cooling effect. The correct installation requires integrated systems.
Concealed in the ceiling. They take the same chilled water (7°C) directly from the Heat Pump. Because they have a drainage connection, we let them "sweat" freely! They pull in the air, trap the moisture (sending it to the drain) and blow out dry, chilled air.
Specialised units installed in the false ceiling and connected to the ventilation ductwork to dehumidify the entire home centrally. Ideal for large residences and commercial spaces.
Fan Coils remove humidity → Humidity drops → Dew Point lowers → The floor can now safely operate at a lower temperature → Cooling becomes effective. The two systems work in parallel and complement each other perfectly.
Underfloor cooling is not air conditioning. It removes sensible heat (warmth), but it cannot remove latent heat (humidity). A cooling system without Fan Coils or central dehumidification is practically incomplete and carries enormous risk for your floors on scorching, humid days.
A reversible Heat Pump (for heating + cooling), thermostats with hygrometer, three-way mixing valve, Fan Coils with drainage connection and a proper HVAC design study.
To the floor: 18–20°C (controlled above the Dew Point). To the Fan Coils: 7°C (free dehumidification via drainage). The two systems work in parallel and complement each other.
Unlike air conditioners, underfloor cooling is 100% silent - no fan, no air current. The cooling comes via radiation, like the coolness of a marble staircase on a hot day.
In exceptionally dry climates (e.g. Aegean islands with meltemi winds), dehumidification may be needed less. But never install underfloor cooling without Fan Coils - even if the installer claims "they are not needed".
⚠️ An underfloor cooling system without Fan Coils or central dehumidification carries enormous risk for your floors, especially on days of extreme heat combined with humidity. Do not risk your wooden floors and your safety!
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