Zehnder ComfoFond-L Q ST

The Zehnder ComfoFond-L Q brine-earth heat exchanger has been developed for use in conjunction with the Zehnder ComfoAir Q350/450/600 comfort ventilation units. It combines the highest comfort with very high efficiency in a compact installation. In winter, when the outdoor temperatures are low, it pre-heats the outdoor air to prevent freezing. This ensures optimum operation of the ComfoAir Q ventilation unit, even at outdoor temperatures below freezing. In summer, the ComfoFond-L Q sub-soil heat exchanger lowers the temperature of the outdoor air, and helps to support a conventional air-conditioning system.


  • Energy saving due to use of renewable energy from the ground
  • Maximum comfort due to pre-heating of outdoor air in winter using geothermal energy and temperature control of outdoor air in summer and winter for a comfortable indoor climate
  • Compact, quick installation directly adjacent to the ventilation unit
  • Simple and sustainable use of geothermal energy with a low power consumption
  • Brine pump with energy efficiency class A
  • Balanced ventilation even with low outside temperatures
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