Silencing a boiler

[WWilts]

How to stop ground floor boiler noise going upstairs to bedrooms or through wall to kitchen? Yet to be installed.
Probable location: in a utility cupboard about 1000mm square, with blocks on 3 sides (incl external wall) & cupboard doors at foot of stairs.
All this is still being built (1m high from floor level so far)

Options considered so far:

Acoustic box with mass loaded vinyl (around boiler only)
Fibreglass curtains across the doorway of the utility cupboard (washing machine & tumble dryer will live there too)
Soundproof doors
Parge coat of 3 walls

 

Others? One obvious solution that works?

 

PS

Boiler dimensions about 700 mm x 350 x 400
Noise level about 55dB. Presumably lots of low frequency noise.
 

 

[SteamyTea]

I assume this is a gas boiler?

Ask the resident expert @Dave Jones he claims his is silent, unlike all ASHPs which have to be noisier.

 

I have recently been staying in a house with a gas boiler.  I was surprised how noisy it was.  Not a horrible noise, just a background roar.

I will be back there next week, so may take some sound readings.

 

I am also surprised, in my house, how good the cheap, panel doors are at reducing noise.  I can heat my E7 cylinder heating up when I am in the kitchen, but not upstairs when I am next to it.

[WWilts]

2 hours ago, SteamyTea said:

I assume this is a gas boiler?

Yes

[Nickfromwales]

Do you really expect a new gas boiler to be this noisy?

[WWilts]

55 dB is the claimed performance. Google searches suggest low frequencies are the main challenge. 
Family members concerned about boiler noise going upstairs.

Any recommendations for 21kW boiler that is relatively silent?  

Edited October 24, 2021 by WWilts