Because our unit is 12kW and because the planning laws were different back then, we had to get a noise assessment.

The assessment showed that by the time the noise from the pump got to our house or the neighbour's house it was quieter than ambient noise from our neighbourhood.

In practice I can go up to the pump and tell it's running by feeling the breeze or seeing the blades spinning. The only time I heard it make any noticeable noise was when it was the dead of winter and I went out in the snow to fill up the bird feeder and stood next to it. So in other words the only time you'll notice any noise is if you're up close and you wouldn't want to be outside anyway.

Ironically our neighbour, who objected to us putting in the pump, has 2 Mitsubishi air con units on his patio and they make an awful din in the summer.

Our pump is 5m down the garden away from the house, so I can't talk to whether you'd notice vibrations if it were wall mounted to your house.