Mechanical Extract Ventilation (MEV)

Mechanical Extract Ventilation (MEV) refers to both centralised and de-centralised systems which provide ventilation helping to reduce excess moisture using either a multi-point extract or single fans in wet rooms. MEV systems provide year-round good indoor air quality, protecting your home from condensation and mould.

MEV systems also come with a 2 year guarantee, giving you peace of mind when purchasing.

MEV is required when:

• You are doing a full renovation or building a new house rather than a retrofit.

• You want an easy to install, whole house ventilation solution.

• You want a fit and forget solution.

Mechanical Ventilation with Heat Recovery (MVHR)

Mechanical Ventilation with Heat Recovery (MVHR) is a whole‑house system that continuously supplies fresh, filtered air while extracting stale, moist air from kitchens, bathrooms, and other areas. A built‑in heat exchanger recovers up to 90% of the heat from the outgoing air and uses it to warm the incoming fresh air, without the two airflows mixing.

Key benefits:

• Improves indoor air quality by filtering dust, pollen, and pollutants

• Reduces heating costs by recovering otherwise wasted heat

• Helps prevent condensation and mould growth

• Provides consistent, draught‑free ventilation all year round

Positive Input Ventilation (PIV)

Positive Input Ventilation (PIV) also sometimes known as positive pressure ventilation work as a whole house ventilation system and create healthy living environments by supplying filtered air into a property at a continuous rate throughout.

Ventilation is mainly used to control indoor air quality by diluting and displacing indoor pollutants; it can also be used for purposes of thermal comfort or dehumidification. Positive Input Ventilation or PIV Systems work by encouraging the movement of air from inside to outside from a unit that is usually installed in a loft. These units reduce condensation and mould by replacing humid stagnant air with filtered air.

PIV is recommended in situations where:

• You don't want to do a full renovation.

• You require a whole house ventilation solution.

• You don't want to remove any walls or go back to brickwork.

Demand Controlled Ventilation (DCV)

It’s a ventilation control strategy where the airflow rate is automatically adjusted based on real-time demand, typically measured using sensors such as:

• CO₂ sensors (to measure occupancy levels)

• Humidity sensors (to detect excess moisture)

• VOC sensors (to detect air pollutants)

Instead of running the ventilation system at a constant rate, DCV only increases airflow when required, for example, when a meeting room fills up with people or when humidity levels rise in a building.

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Decentralised Mechanical Extract Ventilation (dMEV)

Decentralised Mechanical Extract Ventilation (dMEV) is a continuous ventilation system designed for individual rooms, typically wet areas such as bathrooms, kitchens, and utility rooms. Unlike centralised systems, each room has its own low‑energy, continuously running extract fan. These fans remove moist, stale air directly to the outside, helping to prevent condensation and mould.

dMEV fans often have trickle and boost modes, running quietly at a low rate most of the time, then increasing airflow automatically when humidity or usage levels rise.

Key benefits:

• Continuous, reliable extraction for improved air quality

• Targeted moisture control in problem areas

• Energy‑efficient operation with low running costs