Mould (also called fungi or mildew) is an organism that is found both indoors and outdoors as they are a natural part of the environment, and play an important role in breaking down and digesting organic matter. Mould spores travel through the air, and if they land on a wet or damp spot they can begin to grow.
Mould is an almost unavoidable issue in homes around New Zealand, as wherever there is moisture there is a high chance that bacteria and mould can form and grow. Not only can this usually occur in and around bathrooms and laundry’s etc., but it can also occur in your heat pump / air conditioner.
During the cooling process of an air conditioner, the indoor coil temperature will at most times (depending on the relative humidity) be below the dew point of the surrounding air, and as a result, condensation will form on the coil. This condensation will then flow into the drain pan of the unit and then out the drain pipe to the drainage point. During periods of warm weather, and taking into account water tension, the drain pan may have prolonged periods of time where water may be in the drain pan.
Heat pumps / air conditioners also circulate large amounts of air, and the air circulated around the room carries dust, organic matter, and mould spores, in which case regular maintenance is required e.g. cleaning filters, and in some instances, more thorough maintenance is needed.
The growth of mould within a heat pump / air conditioner is not a manufacturing defect, as it is an environmental issue that is controlled by regular maintenance/cleaning similar to performing regular cleaning in the bathroom to prevent mould from forming there.
To remove the mould you will need to hire the services of a professional that speciailises in the cleaning of heat pump / air conditioning equipment.