Recommended Types of Ventilation
Continuous Extract Ventilation (dMEV / MEV)
Mechanical Ventilation with Heat Recovery (MVHR)
Continuous Extract Ventilation (dMEV / MEV)
Continuous systems run at a low level all the time, providing consistent background ventilation.
dMEV fans are installed in individual wet rooms, while MEV systems can extract from multiple rooms via a central unit.
Best suited for ongoing condensation and mould issues
Provides consistent and reliable airflow throughout the day
Positive Input Ventilation (PIV)
Mechanical Ventilation with Heat Recovery (MVHR)
Continuous Extract Ventilation (dMEV / MEV)
PIV systems introduce filtered air into the property, usually from the loft space.
This creates a slight positive pressure that helps push moist air out and reduces condensation levels throughout the home.
Best suited for whole house condensation issues
Particularly effective in properties with limited existing ventilation routes
Mechanical Ventilation with Heat Recovery (MVHR)
Mechanical Ventilation with Heat Recovery (MVHR)
Mechanical Ventilation with Heat Recovery (MVHR)
MVHR systems provide continuous ventilation while recovering heat from outgoing air.
Fresh air is supplied to living areas while stale air is extracted from wet rooms, improving air quality while maintaining energy efficiency.
Best suited for modern airtight homes or major renovations
Higher installation cost but offers the most efficient long term solution
Non-Recommended Types of Ventilation
Natural Ventilation
Intermittent Extract Fans
Intermittent Extract Fans
Natural ventilation relies on air movement through openings in the building.
This includes open windows, trickle vents, air bricks, and chimneys. While this method has traditionally been sufficient in older properties, modern upgrades such as double glazing and increased insulation often reduce natural airflow.
Best suited for older, less a
Natural ventilation relies on air movement through openings in the building.
This includes open windows, trickle vents, air bricks, and chimneys. While this method has traditionally been sufficient in older properties, modern upgrades such as double glazing and increased insulation often reduce natural airflow.
Best suited for older, less airtight properties
Limitation: airflow is unpredictable and heavily dependent on weather conditions
Good for: background airflow
Limitations: inconsistent, weather dependent, often inadequate in modern homes where heat retention is a concern
Intermittent Extract Fans
Intermittent Extract Fans
Intermittent Extract Fans
These are the most commonly installed fans in UK homes and operate only when needed.
Typically found in bathrooms and kitchens, they remove moisture at source when switched on manually or triggered by humidity or timers.
Best suited for localised moisture control
Limitation: no continuous airflow, often underperform due to poor ducting or installation.