A cartridge for an aerosol-generating system is provided, including: a liquid storage portion including a housing containing a liquid aerosol-forming substrate, the housing having an open end； and a fluid-permeable heater assembly including: an electrical heating element configured to heat the liquid aerosol-forming substrate to form an aerosol, the electrical heating element including a planar filament arrangement having one or more electrically conductive filaments, an electrically insulating substrate including a ceramic material and having a planar attachment face, the filament arrangement disposed in contact with the planar attachment face, and connectors arranged at opposite ends of the electrical heating element and forming two separate electrical contacts configured to apply power to the filament arrangement, the fluid-permeable heater assembly being arranged over the open end of the housing.
