Climate mitigation pathways impose uneven burdens across income groups, yet analyses typically focus on revenue recycling rather than on how pathway architecture shapes distributional outcomes. We examine 17 pathways to 1.5°C and trace their impacts to household energy burdens across income deciles in India and the United States. Pathway architecture is a primary determinant of whether mitigation is progressive or regressive. Technology, pace, and cost-optimal pathways are regressive: the poorest households bear cost increases up to an order of magnitude larger than the richest. Demand-side pathways lower carbon prices by curbing demand among high-income consumers, creating development space that alleviates burdens in developing countries. Historical responsibility pathways with international transfers generate progressive outcomes for recipient countries at the expense of donor households. These patterns persist under consumption rebound, albeit attenuated. Distributional consequences are embedded in pathway design, not correctable through revenue policy alone.