Well it makes more sense finacialy to use steel framing instead of aluminum.

Kelly. you need to check your math on your MWh to CO2 conversions. Your numbers are inconsistent. Also for an apples to apples comparison you need energy per frame, including required coating for steel and differing fabrication energy costs. Energy per ton of metal is pretty useless. Lastly, you need to factor in the near universal recycling of aluminum and the vast energy savings achieved when this is done. On more point of fact. You say steel is inherently stronger than aluminum. Since all other measurements in your article are by weight, this is false. Aluminum is far stronger than steel by weight. That is why they don’t make steel airplanes.

In the article, it says: “it takes 13.5 MWh of thermal power to produce one tonne of aluminum (equivalent to 11.2 tonnes of CO2), while it only takes 4.5 MWh to make one tonne of steel (1.8 tonnes of CO2).”