To address all four questions, we first developed a capacity-fade economic model for DAC that includes sorbent degradation. We used the model to explore how various types and rates of sorbent degradation affect the viability of DAC, specifically through the carbon footprint and cost of captured CO2. The most critical sorbent characteristics and process features for minimizing the carbon footprint and cost were identified. We then experimentally synthesized a series of polyamines functionalized with various side chains (methyl, propyl, and 2-hydroxypropyl, with the latter made via 1,2epoxypropane functionalization) in mesoporous silica SBA-15 supports. The functionalization is used to systematically alter the working capacity, energy requirement, and degradation rate, and the experimentally-measured parameters are integrated into the model to compare the economic feasibility. Combining a capacity-fade economic model with experimental tuning of sorbents provides insight into how competing sorbent properties balance and influence the overall cost of direct air capture. These findings provide guidelines and priorities for sorbent performance properties as scale-up of DAC processes is pursued.