I'd pick #1 too. It's the clearest and simplest one, IMO.

Oh, that's nice to hear, thank you!

I already had some sales. Just thinking about how would I ask them for testimonials xD Maybe I'll just ask by email if they are willing to give them.

Fantastic feedback, thanks!

Yeah, I am still playing around with the price. I was planning to sell it as a package with a calculator, but you might be right; if the person wants just an eBook, it's quite a steep price to pay. Maybe I need to create two bundles: just a book and another with a calculator, future updates, etc.

Will add other things, thanks!

I had one with the tube that goes out of the window around 7 years ago, and it was absolutely terrible. I couldn't close my window, it was extremely noisy, it was constantly leaking, and it didn't cool that much, to be honest (partly because the window was open as well). Maybe there is a better model nowadays, though, but make sure to check the reviews.

I'm not sure what the costs are for proper ACs in Berlin, but here in the Netherlands, they cost around €2k-€2.5k. I'd rather overpay a bit but get an adequate AC.
Also, try to install it in winter, they usually way cheaper.

Another route that I decided to take eventually is a hybrid heat pump (it still requires drilling into the wall) and a standing AC unit, which connects to your radiator, so no drilling is required (www.quatt.io/quatt-chill). In that case, you would also replace most gas usage with electricity.

I think there are many people on YouTube who are doing this, and it usually goes well with visual content. I watched several "I Built My Van" series, and building a cabin seems even more interesting.

I'm not sure about Twitter, though. I'd prefer something less obscured by the algorithm. But it might work, too.

Thank you! I'll check it out!

I fully agree with @hboon. Checking the previous issues is crucial for me to decide whether to subscribe or not.
I'd also make "1300 founders read it" much smaller.

I'd check popular platforms like Substack and others, see their UI, and steal parts from it. I think they put tons of research into making people subscribe.

PS Also, I think you need to add a link to the newsletter in this post :)

Thanks for the tips and the course link!

Do you narrow your audience type right away or give broader settings and leave it up to the algorithms?

For keyword research only, I'd recommend using Keywords Everywhere or Keysearch instead.
They're as good, but at a much lower price. In combination, I don't feel the need to use ahrefs (although it's fantastic, of course).

There is nothing better than YouTube for making video content.
TikTok/IG are also good options for making short videos.