What is Mechanical Ventilation with Heat Recovery?

MVHR provides fresh filtered air into a home 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.

An MVHR unit is constantly ventilating a property, meaning that everyday moisture has no time to settle on surfaces as it is extracted to the outside, eliminating the risk of structural and cosmetic damage caused by condensation and mould. They are also extremely efficient, being able to recover up to 90% of heat lost through extraction and transferring it to incoming air.

Benefits of Heat Recovery Ventilation

MVHR systems are considered the most energy efficient method of ventilating an airtight dwelling and offer benefits to your health and your home.

  • Constant cleaned, warmed, fresh filtered air
  • Reduces symptoms for asthma and allergy sufferers
  • Contributes to the energy efficiency of the home

How does MVHR Work?

MVHR systems work on air supply, air extract within the building. A heat exchanger in the MVHR unit is at the heart of the system, whilst fans provide the air movement.

  1. Habitable rooms are provided with fresh air and wet rooms and kitchens are extracted on a continual basis.
  2. Before the extracted air is exhausted out of the building, the heat in the air is transferred by means of a heat exchanger into the fresh air, which is introduced into the building.
  3. The pre-warmed fresh air is introduced into all habitable rooms on a continual basis. Thereby the need to completely heat the fresh air as it enters the building is eliminated. Efficient systems typically heat cold outside air from 0ºC to 18ºC through the heat transfer, when the extract air is 20 ºC.
  4. No extract air is re-introduced or re-cycled, thus extracted germs and pathogens will not spread through the system.
  5. A gentle cooling effect in the warm season is achieved by a potential summer bypass. The cooling effect is limited and needs to be supplemented by cross-ventilation if there are excessive solar gains.