Hi
I'm sorry you have been impacted!
As a host with these significant impacts, I would be immediately offering a partial refund. I have done so when oven has failed, roof has leaked over a bed, etc etc.These are impacting events just like no water or A/C working. I think what is fair is at least 2 nights free given you have a 6 night stay.
I had a TV stop working, but that I did not refund for. There was another TV in another lounge room. And I replaced in 24 hrs on Day 2 of their Day 7 stay.
Guests know these things are usually outside host control, but it is still impacting their stay, and it is the cost for the host of doing business.
Because the host hasn't indicated anything, you have every right to mark them down in the review if they don't offer some compensation. Definitely ask, its a shame that you have to, and see how you go. Don't do your review until you have some resolution you are happy with. You have 14 days, if you don;t get any money back from host, then you can do a review of host indicating that they didn't satisfactorily resolved some major issues and complain to airbnb to see if you can get some money back. I don't know if this will work, haven't had this happen to me.
Was this a super host? It sounds like not? I only ever book with super hosts as I expect a superior level of guest service.
Hope this helps]
Regs
MK