Extractor fans remove moisture at source in bathrooms and kitchens. A PIV unit supplies filtered air to the home and may help dilute indoor humidity. The right option depends on the building, existing ventilation and diagnosed cause.
Start with source extraction
Effective kitchen and bathroom extraction deals with moisture where it is generated. Fan performance can be reduced by long or restrictive ducts, dirty grilles, unsuitable controls or a lack of replacement air. These issues should be checked before assuming the fan itself is too small.
Where PIV may fit
A PIV unit is commonly installed in a suitable loft and introduces filtered air to the dwelling. It may help with whole-home humidity where the layout, loft conditions and air escape paths are appropriate, but it does not repair leaks or replace source extraction from wet rooms.
Flats, homes without a suitable loft and properties with combustion appliances or unusual ventilation arrangements need particular care. Product selection and installation should follow the property assessment, applicable requirements and manufacturer guidance.