After how many days of a not-working heating in the whole building that you live in, would you ask your landlord for less rent?
I don't need/have heating, but I'd ask them about it first. If they have no intention of fixing it, then I would immediatly ask for a rent decrease
Retrospring uses Markdown for formatting
*italic text* for italic text
*italic text*
**bold text** for bold text
**bold text**
[link](https://example.com) for link
[link](https://example.com)
