Air humidification simply explained:
What is a diffusion humidifier?
How a diffusion humidifier works
Diffusion humidifiers are based on the principle of natural moisture diffusion through a waterproof but breathable membrane. This concept is also applied in modern functional clothing to remove moisture from the body in the form of water vapour. Materials that can only be penetrated by water vapour are used here also. Although the membrane is completely impermeable to liquid water, it is highly permeable to water vapour. This enables very effective moisture diffusion while preventing the air flow from coming into contact with wet surfaces.
Installing a diffusion humidifier is simple as the system can be installed in the plant room without the need for major conversion work and uses the existing controlled domestic ventilation network. The duct element is inserted into the supply air duct of the controlled domestic ventilation. The hydraulic box supplies the duct element with tempered water. Existing heat sources such as underfloor heating, a heating circuit or even domestic hot water preparation can be used to treat the humidifier water energy-efficiently. And with an existing photovoltaic system, it can be self-powered.
Patented diffusion fleece
The patented diffusion fleece is based on a highly-efficient sterile membrane. It is arranged as a compact fleece package through which humidification water flows. Although the diffusion fleece is completely impermeable to liquid water, it is highly permeability to water vapour. This enables very effective moisture diffusion while preventing the air flow from coming into contact with wet surfaces.
Unwanted water components cannot penetrate the sterile membrane. The fleece structure was designed in such a way that only very little space is required for the actual humidification process.
Humidifier unit (duct element)
The aesthetic chassis made of powder-coated sheet steel is used to hold the fleece package and is easy to integrate into the air duct. Matching connection pieces are available in different sizes, making the installation as easy as possible. The required water connections are already pre-assembled. Installation in the air duct can therefore be carried out quickly and accurately.
Hydraulic unit
The unit control and all hydraulic components are combined in the control unit in a compact manner. The humidity values are set quickly and easily via an ergonomic touch-screen display. The control unit can be connected to Smart Home systems as an option. For easy installation, all cable connections are also pre-mounted here.
System structure & model overview
A HumiLife controlled domestic ventilation humidifier consists of the hydraulic unit and the humidifier unit. It is available in four versions and at two humidification capacities (1 kg/h or 2 kg/h). The humidifier unit is installed at least 300 mm above the hydraulic unit in the central supply air duct upstream from the distributor and downstream from any existing silencer. It can be mounted on the ceiling (standard) or on the wall (optional). The hydraulic unit is mounted on the wall at least 300 mm below the humidifier unit using the supplied mounting rails. The water circulating in the humidifier is heated in the hydraulic unit depending on the required humidifier capacity (25 to 45°C). This heating can be carried out using various methods. These methods or the conditions on site define the design of the hydraulic unit:
EL variant
Heating of the humidifier water with integrated electrical heating. In this variant, the humidifier water is heated using heating elements in the hydraulic unit’s water tank.
FB variant
Heating of the humidifier water via a heat exchanger connected to an underfloor heating system. In this variant, the humidifier water is heated via the heat exchanger integrated into the hydraulic unit, which is in turn connected to the heating circuit of an underfloor heating system. The heating water circuit is ensured by means of the circulation pump of the underfloor heating. If the underfloor heating flow is rarely or never above 29°C, ordering an optional heating element to be installed in the water tank is recommended. This ensures an optimal supply of moisture to the living spaces even during very cold periods in winter.
HW variant
Heating of the humidifier water via a heat exchanger connected to the hot water system of a heating system. In this variant, the humidifier water is heated via the heat exchanger that is integrated in the hydraulic unit, which is in turn connected to a hot water storage tank. The hot water circuit in this variant is ensured by a pump in the hydraulic unit, which can be operated autonomously from the existing heating circuit.
WW variant
Heating of the humidifier water via a heat exchanger connected to the hot water system. In this variant, the humidifier water is heated via the heat exchanger integrated into the hydraulic unit, which is connected to the hot water system (heated drinking water). The hot water circuit in this variant is ensured by a pump in the hydraulic unit, which can be operated autonomously from the existing hot water circuit. Note: The max. hot water temperature is 65°C. A reduction below 45°C must be avoided in order to ensure continuous control of the heat transfer and thus an optimum supply of humidity to the duct air.
Condair HumiLife humidifier for controlled domestic ventilation
Model |
Humidification capacity* |
Heating type |
Condair HumiLife EL |
2 kg/h |
Electric heating element integrated into the hydraulic unit’s water tank |
Condair HumiLife HW |
2 kg/h |
Heating water (47°C - 65°C) |
Condair HumiLife FB |
2 kg/h |
Underfloor heating (min. 29°C) |
Condair HumiLife WW |
2 kg/h |
Hot water (45°C - 60°C) |
* The stated humidification capacities are maximum values. The effective humidification capacities depend on the performance of the heating source, the condition of the supply air and the configured humidity setpoint. The capacities have been measured by the Fraunhofer Institute for Solar Energy Systems ISE at Freiburg, Germany. The functionality of all basic models can be extended through the addition of various options.
Various accessories and consumables are also available.
Humidifier structure
The HumiLife humidifier consists of a hydraulic unit and the humidifier unit. The humidifier unit is installed at least 300 mm above the hydraulic unit with transition pieces in the central supply air duct upstream from the distributor and downstream from any existing silencer. The humidifier unit can be mounted on the ceiling (standard) or on the wall (optional).
Power supply
The hydraulic unit is equipped with a 3-metre mains cable with Euro plug and is connected to a three-pin mains socket 200 to 240 VAC, 50/60Hz. The mains socket must be protected by a separate FI switch (max. 30 mA) and a separate circuit breaker (min. 10A, slow). The control and monitoring devices (humidity and temperature sensor, maximum hygrostat, airflow monitor) are supplied via an internal 24 VDC voltage.
Water drain
The water drain of the hydraulic unit is connected to the building’s waste water pipe via an open drain funnel with siphon.
Fresh water installation
The HumiLife humidifier comes with a filling cup tested by DVGW [German association for gas and water] and can be connected to the drinking water pipe directly.
Leakage kit
If the room where the humidifier is installed does not have a floor drain, installing the optional leakage set is recommended.