Aerosol-generating system having a fluid-permeable heater assembly

An aerosol-generating system, comprising:

• a fluid-permeable electric heater assembly, the fluid-permeable electric heater assembly including:
• an electrically insulating substrate;
• an aperture formed in the electrically insulating substrate;
• and
• a heater element fixed to the electrically insulating substrate, the heater element spanning the aperture and comprising a plurality of electrically conductive filaments connected to first and second electrically conductive contact portions, the first and the second electrically conductive contact portions being disposed on opposite sides of the aperture to one another, and the plurality of electrically conductive filaments forming interstices, and
• a liquid storage portion comprising a housing containing a liquid aerosol-forming substrate,
• wherein the first and the second electrically conductive contact portions are configured to allow contact with an external power supply;
• wherein the aerosol-generating system has a longitudinal axis and the heater element is substantially flat and extends parallel to the longitudinal axis;
• wherein the heater assembly is fixed to the housing of the liquid storage portion;
• wherein the liquid storage portion is disposed on a first side of the electrically conductive filaments;
• and
• wherein an airflow channel is disposed on an opposite side of the electrically conductive filaments to the liquid storage portion, such that air flow past the electrically conductive filaments entrains vapourised liquid aerosol-forming substrate.