An aerosol-generating system comprising a main unit (10) and a cartridge (20) that is removably coupled to the main unit, wherein the cartridge comprises a liquid storage portion containing a liquid aerosol-forming substrate and a fluid-permeable heater assembly (30), and the main unit comprises a power supply, the heater assembly comprising:an electrically insulating substrate,an aperture being formed in the electrically insulating substrate； anda 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 second electrically conductive contact portions positioned on opposite sides of the aperture to one another,wherein the first and second electrically conductive contact portions are configured to allow connection with the power supply, and wherein the heater assembly is provided at an end of the cartridge that is opposite to a mouthpiece portion (12) of the system.
