Don’t send spam, behave nicely, have proper configuration on postfix and dovecot, set up SPF and preferably DKIM, keep your domains reputation clean and so on. You’ll likely still end up on some lists, so you need to manually dig them trough and ask nicely for removal.

Self hosting email has a pretty bad reputation and many will strongly advice against it, but in reality it’s really not that bad. But email as a whole is more complex beast to manage than simple website or running Jellyfin for your family and friends. You need to understand how the mail routing side of things work (SMTP itself, authentication for it encryption included and so on) and also you need to understand how DNS works and how various entries are related to mail transport. Then you’ll likely want at least some kind of spam filtering and so on. And with email you’ll need to have proper backup scenario too so that you don’t lose the likely pretty important data. All of that is perfectly doable and it’s not as difficult as many claim it to be, but there’s a bunch of stuff you need to understand and implement all of them correctly.

There’s various permission errors on the log file, I’d start from those. Also your dovecot configs seem a bit funny to me, usually mails are not stored to user home directories with dovecot, but instead somewhere under /var, likely you’ll want /var/vmail. Logfiles are pretty good with these tools, so pay close attention to those.

And take your time to understand what the config options actually do. Too permissive configurations will get your sever to every spamlist on the world pretty quickly.

Fines are just the cost of doing business.

In theory fines in EU don’t have a ceiling. 10% fine of companys turnover with OpenAI (or any other company running on borrowed money) would be a pretty steep cost of doing business and I don’t think all (if any) of AI-hype entities could actually swallow that.

Obviously that’s just in theory, so far the fines have been a slight slap on the wrist, but mechanisms are in place to give actually meaningful fines for unethical practices. No one will go to jail tho, as EU doesn’t really have the power to jail US citizens.

That style stoves are pretty common around here on older buildings. We have one and it really helps during winter and cuts down the electricity bill, at least as long as we have enough firewood to keep that thing going.

The main material could be smashed/pulverized glass.

As in sand. Glass is recyclable material, it makes no sense to use that for this kind of application since sand is already everywhere. Also at least some flavours of glass can melt on temperatures used on these which I’d imagine could cause problems.

I hear aircrete is an insulation thats already prevalent in europe is this true?

At least here in Finland it is not. It could be, but it’s not really widely available right now. Maybe in the future, but that would need at least some changes on how things are built.

It’s interesting piece of technology, but it’s not ‘radical’. The company behind the storage has done their homework and they seem to be well engineered, but the “technology” itself is pretty much as old as bonfires, people have used hot rocks to heat up tents for ‘a while’.

But sand has pretty good thermal properties and size of these new iterations of old tech makes them pretty decent solution for energy storage with renewables. I’ve been following various ‘sand battery’ products for our own house, but the main problem with all of them tends to be the size required. In practise for our own house we’d need a sand battery roughly the size of 6m storage container (with heat pumps and all the other hardware) and that’d be so expensive that the investment wouldn’t pay itself back in my lifetime.