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Introduction to MVHR

Mechanical Ventilation with Heat Recovery is an ideal solution for controlled ventilation in any modern home.

A central unit is installed in a hot press, utility room or attic. Extract ducts are piped to each wet room where moisture is generated, e.g. Kitchen - Utility Room - Bathrooms - WCs. The unit then extracts the stale air from these rooms and uses it to preheat incoming cold air. This warmed air is then supplied to all the inhabited rooms. MVHR units are up to 90% efficient at recovering heat from the extracted air.

Why choose a MVHR unit?

By law, there are only two permissable ways of providing ventilation in a home. According to part F of the building regulations, the following methods are acceptable methods of ventilation:

A. Natural fresh air supply via vents with extract ventilation provided by fans or passive stack vents

Natural Ventilation with Mechanical Extract
Natural Ventilation with Mechanical Extract

Using this method, fresh air is supplied through vents in each room. Extract fans or passive vents allow for extraction of stale air. In small homes or apartments, this may provide a valid option. However, the more vents and fans that are used, the worse the Building Energy Rating of the home will be.

B. Mechanical ventilation with heat recovery (MVHR)

Mechanical ventilation with heat recovery (MVHR)
Mechanical ventilation with heat recovery (MVHR)

Using Mechanical ventilation with heat recovery is a better option in most cases. MVHR systems can provide better control of ventilation, leading better air quality, excellent comfort for inhabitants, and improved BER ratings in most cases.

Benefits of a MVHR unit from RVR

RVR supply products from French company Aldes. They are one of the largest ventilation manufacturers in Europe and have annual revenues in excess of €200m.

What makes the Aldes System Unique?

  1. The Aldes MVHR unit provides a constant airflow so one simply sets the ventilation level needed for the dwelling. The unit adapts the fan speed to maintain constant airflow even when filters get dirty.
  2. Intelligent self balancing extract grilles control the extract rate from the wet rooms according to the humidity level or occupancy. Other systems use crude core grilles which do not vary the airflow and are almost impossible to balance.
  3. Supply airflow is balanced using specially designed Aldes distribution units. These ensure that the correct airflow is supplied to all outlets.

These important system features ensure that the system is self balancing and truly PLUG AND PLAY.


An Aldes MVHR unit has the following benefits:

  • Improves comfort and hygiene in the home
  • Saves energy by recovering wasted energy from wet rooms
  • Self-balancing system is easy to install and commission, unlike other MVHR units
  • Micro-watt motor offers excellent efficiency
  • Boost mode for optional use during cooking

Further information

For further information on system sizing, installation and ducting, please read the associated pages in the menu to the left.