Making a brand new house low-carbon costs either £5k if built like that, or £20k to householder after, for retrofit. If kitted out at construction, inconvenience + some cost borne by housebuilder; if later, all by homeowner. Guess which happens in UK? https://www.theguardian.com/environment/2021/jan/23/buyers-of-brand-new-homes-face-20000-bill-to-make-them-greener?CMP=Share_iOSApp_Other

Btw, we don’t have to wait for the technology to make houses low-carbon to be beamed in from an alien civilisation - it exists now. Housebuilders just don’t build it in as standard to new UK houses because it would cost them (a very small amount).

And it is easier for them to pass the buck on to homeowners, who will have to pay for their brand new home to be retrofitted at some point, as well as facing higher bills in the meantime.

And who could force the housebuilders to do the right thing and make new houses low-carbon now, as standard?

Well, that would be the government, wouldn’t it. Who are planning to build more than 1m houses before they bring in rules that would require them to be low-carbon.

Thus saving the construction industry £5k on each of those new houses. £5k x 1m. Not a bad return on the housebuilders’ investments on lobbying and influence.