Decentralised Mechanical Ventilation with Heat Recovery dMVHR

Welcome to the forum @Amy_Squire.

Generally over specified units are quieter as they will not be running outside their comfort zone. You set a restriction to your required air change rate when setting them up.

The topic has been discussed in a few threads. Have you tried searching for dMVHR, distributed MVHR or decentralised MVHR?

You could start with