> Copper is used for 12 and 14 gauge branch circuits. Aluminum branch circuits are currently strongly discouraged.
Maybe you're already saying this: there was a period (maybe ~70s) where aluminum was used for household wiring because of the advantages you mention. Unfortunately it oxidizes resulting in higher resistance leading to heat and potentially fire at connections. Where I am, insurers ask you if you have aluminum wiring when you buy a house (and penalize you for it), and it is generally regarded as a failed experiment.
Maybe you're already saying this: there was a period (maybe ~70s) where aluminum was used for household wiring because of the advantages you mention. Unfortunately it oxidizes resulting in higher resistance leading to heat and potentially fire at connections. Where I am, insurers ask you if you have aluminum wiring when you buy a house (and penalize you for it), and it is generally regarded as a failed experiment.