Is the ventilation system noisy?

The ventilation system itself is housed in a very well insulated and airtight cabinet which is normally positioned in a utility room. The noise from the fans is no greater than that from a modern fridge. The ducting is fitted with what are referred to as ‘attenuators’ and combined with acoustic insulation, which reduce the sound of air passing through the system. In bedrooms, if designed correctly and properly fitted, air passing through the system should be barely audible at normal flow rates.