AirBnb Guest: How much of a refund to request? [Canada]
I am currently in a basement apartment for an eight-night stay. The place is well rated, clean, good kitchen items. There is only one issue - there is a water heater on the other side of the bedroom wall at a constant low-grade rattle. It becomes louder and disruptive for several minutes at a time (it woke me up yesterday morning at 7:45am) when the family upstairs uses water.
The host checked on the heater, agreed it gets louder with use, but didn't say anything about a fix. She said they would avoid water use after 9:30pm but couldn't do anything about the morning. She suggested I use ear plugs or a white noise machine they provided.
There is nothing on the posting about this issue. The louder mechanical stuttering is impacting my sleep in the morning and now the low rumble is testing my sanity.
I am thinking about leaving but I need the place for its proximity to a workshop I'm attending. What is best way to handle a refund? I was thinking 25% but am wondering if it should be more. I tend to lean on the understanding/peacemaking side and don't want to ask more than is fair, especially if I endure the noise and stay here. Thanks for any suggestions!
Edit: Thanks to a few commenters for the clarifications that a refund is only if I decide to leave. This doesn't seem quite fair, as I can't afford a last-second alternative in the area. Strange that there isn't a solution for "this is definitely not what I'm paying for". Is this hotel brain?