Table 1.

Suitability of household-scale applications by AWH category

	Passive AWH devices	Active AWH devices
Diurnal AWH (single cycle per day)
Device types:	Dew harvesters (near-condensed droplets)	Sorption-based
Energy Requirements:	None	0 to 1 l kWh−1 (ref. 32)
Size requirements:	Low mass, but requires large catchment surface area	Mass-driven: water outputs scale proportional to sorbent mass37
Global assessment:	Niche potential7	Wide climate applicability but mass intensity limits economic reach7,31
Continuous AWH (or multiple cycles per day)
Device types:	Fog harvesters (pre-condensed droplets)	Sorption-based, cooler–condensers*
Energy requirements:	None	Sorption-based: 0 to 1 l kWh−1 (ref. 32); cooler–condenser: 2 to 4 l kWh−1 (ref. 32)*
Sizing requirements:	Low mass, but requires large catchment surface area	Climate-driven and modular: scaled by available resource and solar harvesting area4*
Global assessment:	Niche potential7	Global potential not previously studied12†

Select categorization of AWH devices with low or no energy requirements. *Promising categories for low-cost, off-grid devices at household scale. ^†There is a gap in the literature on global assessment, which is addressed in this study.