Mechanical Ventilation Heat Recovery

MVHR (Mechanical Ventilation with Heat Recovery) provides fresh filtered air into a building whilst retaining most of the energy that has already been used in heating the building.

Heat Recovery Ventilation is the solution to the ventilation needs of energy efficient buildings. Mechanical ventilation with heat recovery (MVHR), heat recovery ventilation (HRV) or Comfort ventilation are all names for the same thing.

A heat recovery ventilation system properly fitted into a house provides a constant supply of fresh filtered air, maintaining the air quality whilst being practically imperceptible.

How it works

MVHR works quite simply by extracting the air from the polluted sources e.g. kitchen, bathroom, toilets and utility rooms and supplying fresh clean air to the ‘living’ rooms e.g. bedrooms, living rooms, studies etc.

The extracted air is taken through a central heat exchanger and the heat is then recovered and put into the supply air, effectively removing excess heat from the warmer areas and recycling that heat into the cooler areas.

This works both ways, if the air temperature inside the building is colder than the outside air, then the cool temperature can also be maintained inside the building.


  • Supply of fresh air to provide good indoor air quality
  • Elimination of bad odours
  • Filtered air: pollen filters are a great advantage for people with allergies
  • Preservation of the building fabric through steady ventilation
  • Keeps mould, fungus and dust mites in check
  • Active dehumidification in the cold season

Green Warmth is Wales longest serving MCS accredited company for renewable heating.

Established in 2007, Green Warmth is a family owned and managed West Wales based independent installer and supplier of renewables. As a trusted MCS accredited installer for heat pumps, solar PV and battery storage solutions, our clients have access to the Boiler Upgrade Scheme (BUS) and solar PV export tariffs.