Action Surrey: Surrey's Low Carbon Community

Call us:

Domestic ventilation systems

30 April 2020

No comments

What types of ventilation systems are there and what do they do?

Mechanical Extract Ventilation (MEV) is a ventilation system for the whole dwelling, extracting air continuously at a low rate. It is designed with multiple extract points in order to draw dirty air out of the various moisture or dust generating rooms within a house.

It is possible to get Mechanical Ventilation with Heat Recovery (MVHR). The aim of this mechanism is to extract air from the rooms that produce dirty air (e.g. bathrooms, kitchens, etc.) whilst supplying clean air through filtration to all habitable rooms. Heat from the polluted air is utilised and fed into the air supply to regulate the temperature of house. Reusing the heat present in the polluted air aids in regulating the temperature of the dwelling without the requirement of additional energy use.

Another option available on the market is natural ventilation and the most effective form of this is Passive Stack Ventilation (PSV). Where the mechanised systems actively extract air, this system relies on the warm air to naturally rise up through vents to the roof where it escapes. Fresh air is drawn in through trickle vents in windows and doors (or other appropriate places). Working without mechanisation does remove the need for any electricity, but this in turn does bring into question the level of ventilation achieved. In comparison to MEV and MVHR this system offers very little control, though it is important to note that it can still be effective (it is just less consistent). Also, due to the design of this sort of system, it is only really appropriate for new builds or major renovations.


Why are these systems important?

The removal of moisture and pollution of the indoor air are important if good air quality is to be maintained. Good air quality is important for many reasons. If we first consider personal health, MVHR systems filter the incoming air (to various extents depending on the model) and so can remove not only pollen, insects and dust from the air supply, but also pollutants related to exhaust fumes. It is clear that this can have a dramatic impact on the long-term health of the occupants in a particular house.

If we consider the health of the property, having any of the above ventilation systems in place can play an important role. When these systems extract polluted air from the various sources within a house, they are working to reduce the likelihood of damp and mould.  If these signs of damage are ignored and allowed to build up then costs may be incurred that could have been avoided had an effective ventilation system been in place.

Having a functioning ventilation system provides a far cleaner environment for occupants and contributes not just to their health but also to the health of the property itself. It is therefore important that we utilise these systems where possible.


The future of residential ventilation:

Ventilation is due to become a central issue as modern housing increases. A central consideration in modern building is quality insulation, and part of this is ensuring that heat can’t escape easily. This is certainly important, but if it is being made harder for air to move in and out of spaces then ventilation systems will be essential to ensure stale, polluted air is extracted and fresh, clean air is supplied. The market for domestic ventilation systems is sure to grow over the coming years.

PSV offers something the other systems can’t, and that is zero energy use. Whilst this is tempting for many homeowners, the reality is that the mechanised systems are far more efficient and reliable in their purpose.

MEV and MVHR are both expected to become increasingly common in houses across the UK, and as a result it is worth considering where this technology is going and how it may look in the future. The most commonplace prediction is that this technology will become “smart”. Much like smart heating controls which have become increasingly widespread, smart ventilation would utilise technology to ensure maximum efficiency. These systems could even work in unison to ensure that optimum comfort is achieved. This would allow energy use in the home to be streamlined.