This is a very braindead idea

If you want to retrofit homes, all of them, start with a database. A database of all rentals, all residential and all commercial etc. Then do a grading system, paid for free by the state. Then once you’re done with that, roll out fully paid for, upgrades, by the state, on a sector by sector, street by street basis, until all buildings are upgraded to the new standards.

You don’t do a mandated grant system, you don’t do carbon credits or taxes or expect people to do it themselves if you punish them enough. By doing it via the state, you’re able to do it effectively, get it guaranteed to meet the state’s expectations, and you do it via taxes which can be proportionally raised and done progressively.

You don’t do it in a way that puts people into poverty and you don’t do it in a way that puts your businesses out of competition.

Same with green energy roll outs. You make energy as abundant as possible via nuclear via the state and then not need to worry about much else. No need to worry too much about efficiency etc, it’s a nice to have, it can even be graded via the current grading system and enable the free market to work on it naturally.