Mechanical Ventilation And Heat Recovery

mechanical ventilation system
The current building regulations demand better insulated and air-tight buildings to reduce the heat loss and therefore the amount of heating the building requires. But air-tight, well insulated buildings prevent natural ventilation which can result in the formation of mould through damp stagnant stale air, both detrimental to the building structure and the health of the occupants.

The standard method of complying with these regulations is to provide extract fans in the wet areas of the house such as the kitchen and bathroom, whilst stipulating that all other areas have minimum ventilation typically provided by trickle vents in every window.

Whilst this addresses the need for ventilation it also means that there can be considerable heat loss.

An alternative is to provide a Mechanical Ventilation system that manages all of the air flows within the house, both in and out, but also incorporates a Heat Recovery unit – MVHR

air flows

How Does It Work?

The extract fan within the ventilation system extracts air from the wet rooms (kitchen, bathroom, WC) on a continual basis, this stale warm air is then passed through a heat exchange. This extracts the heat and passes it onto a supply of fresh, filtered air, that is being extracted from outside and pumped into the other rooms of the house (living room, bedrooms, hallway).

This method means that the fresh air and stale air do not mix. Instead up to 95% of the heat is recovered from the air leaving the building. This is used to pre-heat the fresh incoming air. As a result far less heating is required of the building as a whole

ventilation systems

Benefits Of Mechanical Ventilation

  • Healthy – Fresh filtered air 24/7 – Extracts cooking and other smells
  • Allergy Friendly – British Allergy Approved Filtration
  • Quiet – Cuts out the noise from the street
  • Energy Saving – Reduces the heating demand by 30% or more

Key Selection Questions

What to do if my home gets too warm?

During the summer months, there is a summer bypass system. This means that the intake air will not be diverted around the heat exchange block and only cool outside air will be circulated in the building

Can I leave my windows open?

MVHR units can run with the windows open, however this will make the unit less efficient during the winter months.

How will it work with my heating system?

MVHR systems are designed to ventilate your home, it does not actually heat your home. The two operate completely independently. However, the benefit is that you do not lose the heat you have paid to have generated as you would with a standard ventilation system, as the MVHR system will recover up to 95% of this heat energy.

Is much maintenance needed?

There is very little maintenance, we recommend that you check your unit filters annually. The filters can either be cleaned or replaced. However, this will depend on the environment in which you live and how clean the is the air around your location and your home.

How much will it cost to run?

This can vary depending on factors such as environmental factors and airtightness of your home. MVHR units run typically cost an average of 15p per day for a constant 24hr period

Key System Components

heat exchange unit
Ventilation & Heat Exchange Unit

semi rigid duct
Rigid and Semi Rigid Ducts

grilles and diffusers
Grilles and Diffusers