Fresh-air units


With fresh-air systems consisting of the fresh-air unit, the duct system or piping system and the fresh-air ceiling, the air which has been fed away by the paint-mist exhaust system is replaced.

The fresh-air unit is used to convey, filter and heat up the required outdoor air to the required fresh-air temperature. The unit is equipped with a fan, a plug-in filter and a heat exchanger (heating register).

To save heating energy and to reduce the required heating capacity, the fresh-air unit can be supplied with a second heat exchanger for heat recovery. Via this second heat exchanger, the exhausted warm outgoing-air and the sucked cold outside air are guided and thereby up to 65 % of the heat energy contained in the outgoing-air are recovered. Since generally relatively large volumes of outgoing-air and fresh-air are conveyed, the investment in heat recovery is amortized in a relatively short time due to the expected steadily rising energy prices. Another important factor to be taken into consideration in some cases is the lower required heating capacity. This advantage means for many applications that the heating capacity of the existing boiler system is sufficient to cover the heat demand of the fresh-air.

practical examples

fresh-air unit with outdoor air duct and fresh-air duct as well as heating connection
fresh-air unit in pancake design
Zuluftgerät - Wärmetauscher
movement by crane of a fresh-air unit
fresh-air unit with heat recovery



The fresh-air units are modular and designed as stable box construction, consisting of a hot-galvanized profile frame construction, screwed to corner connectors of die-cast aluminium to form a unit. The profile frame can completely be dismantled and is extremely stable. Into the frame, hot-galvanized, double-skin panels with intermediately positioned sound insulation and thermal insulation are screwed in airtight, being removable from all sides.

The following elements are installed in the fresh-air units:

  • radial fans sucking one-side, particularly quietly working with high efficiency degrees for minimal power consumption. Optionally, the power supply can be made via frequency converter for speed adjustment or speed control.
  • shutter flap on the suction side.
  • bag filter built into a pull-out filter frame to clean the sucked in outside air.
  • heat exchanger (heating register) to heat the pre-filtered outside air to the required fresh-air temperature. As a freezing protection, the heating register is equipped with a capillary tube sensor.
  • suction and pressure side elastic nozzles for connection of the duct system.

Special paint types require compliance with certain target values for both, fresh-air temperature and air humidity. For these applications, the fresh-air unit is additionally equipped with a humidification module and a cooling module. This allows the outdoor air to be cooled and dehydrated (summer operation) or to be heated and moistened (winter operation). Devices of this type are no longer referred to as fresh-air unit but are called air conditioning units.

The fresh-air units and air conditioning units can also be supplied with a weatherproof casing and improved sound insulation for outdoor installation.

SPÄNEX-fresh-air units

standard fresh-air unit with heat recovery
Zuluftgerät mit Wärmerückgewinnung
fan module fresh-air units
Ventilatormodul Zuluftgerät
heating register module fresh-air units
Heizregistermodul Zuluftgeräte
cooling module fresh-air units
Kühlmodul Zuluftgeräte
climate control unit in weather-proof execution with heat recovery
standard fresh-air unit
Zuluftgerät Standardausführung


  • heat exchanger for heat recovery (plate heat exchangers, rotating heat exchangers and circulation system)
  • pneumatic drive for anti-freeze shutter flap
  • motor-three way valve to connect the heating register to the heating system
  • wall consoles
  • weather protection grate
  • directly fired air heater (alternatively to the heating register)


  • variety of execution variants
  • modular construction
  • solid frame construction
  • high total efficiency
  • many accessories
  • serviceability