Let's say it costs £5000 per installation and that has to be spread across 10 million homes, that's £50,000,000,000.... I don't even know what that number means (£50bn?) but what's been committed clearly isn't enough.I did see the size of the thing they were standing next to and thought it might be a problem in most places. I have a first floor flat!
as @inbetween touches on, it'll need a lot of engineers and time to fit them. It has a place, but only as part of a national, very expensive, plan. I don't see much in the Commons to suggest that is more than a pipe dream.
You can see why these things sound a good idea but in practice they're completely ridiculous.
I've just heard Boris say we will have zero emission flights but there is no such thing. Even electric cars don't emit nothing. Tesla's will soon be built in Germany and well that factory will emit something to power it and I don't know of any electric ships that can import them over here.
The biggest problem we have is coping with the fact that reducing consumption is the only way we can solve this problem. Having no car at all for example is 10000x better than having an electric car but has the government announced a massive investment in electrified cheap public transport? Nada.