The Zehnder ComfoClime is an air temperation device which is used in conjunction with the Zehnder ComfoAir Q range of MVHR units. It sits on top of the MVHR unit. The ComfoClime reduces the humidity of the incoming fresh air before distributing it to the habitable rooms. In addition to this dehumidification, it also helps to temper the incoming air, resulting in comfortable supply air during warmer periods. 

ComfoClime isn’t the same as air conditioning, since air conditioning recirculates stale cooled air, whereas the ComfoClime delivers fresh filtered air. This helps to meet ADF ventilation rates whilst having the added benefit of dehumidification and air temperation. The ComfoClime also doesn’t require any external unit like an air conditioner would.

Zehnder ComfoClime with ComfoAir Q

The ComfoClime only works together with the Zehnder ComfoAir Q range of MVHR units, which have a unique modulating summer bypass. If the external temperature is lower than that of the internal temperature, the summer bypass will activate to bring the cooler air into the property without the need for activating the ComfoClime. This can activate down to much lower temperatures than a standard summer bypass, whilst avoiding hitting the dew point due to it being able to partially recover some of the heat. The ComfoAir Q range of units also have three temperature profiles which react to the average external temperature. This means that during spikes in external temperature the unit is more inclined to react to these sudden changes by opening the bypass or activating the ComfoClime accordingly.

There are two Zehnder ComfoClime models available:

  • ComfoClime 24 – Compatible with Zehnder ComfoAir Q350
  • ComfoClime 36 – Compatible with Zehnder ComfoAir Q450/Q600

Enthalpy heat exchanger

We would recommend using the ComfoAir Q range that comes with with a Zehnder enthalpy heat exchanger. This recovers some of the moisture from the extract air and puts it back into the incoming air. Moist air holds more cooling energy and therefore carries a higher cooling load, and so will deliver cooler air to the property than a standard heat recovery heat exchanger. The Zehnder Enthalpy Exchanger is available for all ComfoAir Q models.

Energy modelling at the outset

If you’re considering heating or cooling via MVHR, we always recommend that an energy model is carried out at the outset to determine the heating and cooling load of the building, and whether there is an overheating risk. Whilst the Zehnder ComfoClime is a good option for air tempering it’s important to note that it is not a replacement for good architectural design and energy modelling, such as Passive House’s PHPP.


The ComfoConnect KNX C or LAN C enable the end user to control and monitor the unit using the KNX building automation infrastructure or the ComfoControl free app (available on iOS and Android). These can be used to set activation points including an activation schedule of the ComfoClime in addition to enabling remote activation and support via the ComfoControl app.