We recently moved from London to a country house. Our new neighbors are nice and we get along very well. In August they installed an air source heat pump pool right next to our fence with a fan facing us. This was included as they kept the pool at 31C. They don’t hear it in their house or garden, and we have a constant buzz. Our spare room was almost directly above it, so the windows could not be opened at night.
I mentioned to them and they were very sorry but after talking to the pool company they said there was nothing they could do. I measured decibels – 50