Ensuring adequate ventilation for dwellings is more important than ever before with further changes to the Building Regulations having come into force in October 2010. With Part L dictating that carbon emission levels will have to be cut by another 25% compared to 2006 levels, and Part F ensuring that homes have to become more airtight, it is not surprising that interest in whole house ventilation systems has increased.
The two main types of whole house ventilation systems are Mechanical Extract Ventilation (MEV) and Mechanical Ventilation with Heat Recovery (MVHR). MEV systems can comprise either a whole building central extract system or low energy extract fans in individual rooms. Designed for simultaneous ventilation in separate areas of a building, the unit is located in a loft or airing cupboard, with ducts running to quietly remove pollutants at source from areas such as bathrooms, kitchens and utility rooms. Alternatively, individual continuous running extract fans can be installed to form a MEV system in new or refurbished properties.
MVHR continuously extracts polluted air from a building. This stale air is passed through a heat exchanger, which is then used to pre-warm incoming fresh air. This ensures a fresher, warmer and more comfortable environment. No window trickle ventilation is required avoiding noise ingress issues.
Technological advancements –
Whilst whole house ventilation has been around for decades, major technological advancements have been made in recent years. More energy efficient heat recovery cells have been incorporated that can recover up to 95% of a property’s heat that would otherwise be wasted. A move from AC to DC motors has also resulted in at least 50% less power required to run the system. More recently, EC (Electrically Commutated) motors, which have all the electronics built-in to them, have also been developed to save even more energy. There has also been a growing emphasis on aesthetic appeal, meaning the whole design, look and feel of a solution has been completely transformed.
The fact that these systems need a certain amount of ducting means they are ideally suited to the new build marketplace or the refurbishment sector where ducting can be installed without restrictions. To help, Xpelair has put together a step-by-step installation guide for its Xcell 150QVW – a new generation of MVHR units. With a highly insulated structural foam body and four 125mm top entry spigot connections, the range features a 90% energy efficient heat exchanger, EC ultra low energy multi-speed single inlet external rotor motors and long life G4 filters.
The unit, which weighs only 17kg, can be mounted direct onto a block or brick wall using the 3 mounting brackets supplied. If the wall is low density, a 15mm plywood board should be fixed to the internal frame of the wall and the unit mounted to that. Mark the positions for the holes using the diagram included in the installation booklet and use a spirit level to ensure that the installation will be level when completed in order to ensure effective drainage of condense. The condense drain will require connection to the waste water system via a trap, therefore consideration should be given to this when selecting where the unit will be sited along with future access for routine maintenance. The unit can be mounted R/H or L/H to assist in the later routing of ducting.
The condense drain can now be connected, this must be installed to the wastewater system in accordance with Building Regulation H1. If this is to run through a frost prone area, this will need heat tracing. To access the inner casing, rotate the access cover to the left, this will reveal the heat exchanger and filters, these can be carefully pulled out noting which side of the filters faces the heat exchanger. Fit the drain tube supplied through the hole on the underside of the machine ensuring the end with non slip tape is used. Once the condensate drain assembly is complete, the heat exchanger and filters can be replaced. The heat exchanger retaining bracket must then be fitted and the access cover replaced.