Vents, more often than not, are dysfunctional. Either ineffective or obsolete and need replacing with an appropriate solution or be closed off.
Up to date building code now specifies, this applies to new-build.
– Single Room – Mechanical Ventilation Heat Recovery
– Connect Kitchen extractor to the outside and install good backdraught shutter. Not all extractors have backdraught shutter.
– Bathroom extractor
– Envirovent pressure and humidity controlled unit
SR-MVHR (Single Room – Mechanical Ventilation heat recovery)
– MVHR would extract moist air from kitchen and bathroom and supply fresh air to bedrooms. A good option in a rental property.
Lindab – back draught shutter
[Envirovent – SR-MVHR single room heat recovery unit](https://www.envirovent.com/specifier/products/single-room-heat-recovery-unit/heatsava/)