Insulate glass blocks through a front panel

I think fixed glazing is good – and it is cheaper than windows. Since you will presumably subdivide the surfaces anyway, the frames provide a good design element. I would avoid secondary glazing, that smells like trouble. The only exception is if you do it like in the museum village, then air exchange is ensured. If you shift the dew point, it is still somewhere inside, and it’s not clear where the moisture should go. Show me a facade view of the part with the glass blocks.

Best regards
Gabriele

Only exception, you do it like in the open-air museum village, then air exchange is guaranteed.

I'm confused about this.

You look at monument conservation. I see fascinating solutions, for example at the Vogtsbauernhof, also in other open-air museums, in Tyrol, but actually everywhere where the old building was constructed with enough money and where it gets quite cold in winter. In some areas there are as a treat solutions without metal, great. What you can learn from is basically what is possible to keep out the cold without it turning into a dripstone cave.

But I still messed up, the glass blocks could sit flush in a wall that is too thin, then at least on one side there is no space at all. I don't know any glass blocks that are worth such an effort. If I wanted to save money, I would rather divide the surfaces nicely myself, have the locksmith produce powder-coated frames, get the glazing as a finished composite directly from the glass factory, and put it in.

Best regards
Gabriele

good luck with your house,
you also always have the option to do only the essentials. Roof sealed, downpipes, facade and windows sealed and simply heat expensively (3000-5000€/year should not scare you), 100K€+x full energy renovation might never pay off.
I would renovate with a lot of money and enjoy step by step with little money in EL as a long-term hobby as well
Regards Nida