Boiler in utility room - a few questions

[CobaltRewind]

I’m thinking about different options for my kitchen extension (using garage space)

I definitely need a utility and WC area partitioned off the new living space (with a stud wall.)

The existing boiler is a very decent Grant combi boiler, but it is noisy. I’ve assumed I’ll need to put it outside but someone said it will add extra heat if I keep it in?

How do I get around the noise of it? Yes it’s technically in the next room but it’s only a stud wall. I imagine I would get ‘used’ to the noise and replace with a quieter one when the current boiler came to the end of it’s life span but any idea of things I could do to minimise the noise?

Why is it so noisy?
What sort of noise - the burner (does it need servicing), water gurgles (have you got air in the system).
Can't think of any more reasons myself, but a specialist may be able to improve the situation.

If you put it in a cupboard then you probably won't hear it. I have a utility with stud wall off my kitchen. I couldn't hear my integrated washing machine at all. I now have a free standing one and with the door closed I can't hear it much. We have hard floors and there is a gap under the door - without those I don't think I'd hear it at all. I've never heard the boiler either, although it's quiet anyway.