Paul Croughan, Head of Sales – New build at EnviroVent, looks at how the new build sector is meeting ventilation requirements and improving the air quality in new homes.
The Government’s plan to build at least 200,000 new homes per year by 2020 means the emphasis is on the affordability of new properties, whilst this must be combined with a fabric of the building which is fit for purpose and an internal environment that is healthy for occupants.
Requirements for increased levels of air tightness mean that around 25 per cent of new homes are now being specified with Mechanical Ventilation with Heat Recovery (MVHR) systems, according to research by the NHBC (National Housebuilding Council).
MVHR systems are being more widely specified in order to achieve the required ventilation when building airtight properties. These systems are usually located in a centralised position in the home, either in the loft space of a house or a utility room in an apartment. They provide both supply and extract ventilation, extracting warm and moisture-laden air from the bathroom, kitchen, WC and utility room of a property which is drawn into the main system and passes over a heat exchange cell, before being ducted outside to the atmosphere.
At the same time, fresh air is drawn from outside into the system, the heat from the extract air is then transferred to the supply air through the heat exchanger. Many units can transfer over 90% of the heat from the extracted air to the supply air as it passes through the heat exchange cell. This helps to reduce the overall energy requirement of the building, as well as its carbon footprint. This fresh, filtered and tempered air is then supplied into the living areas of the home. The result is that it reduces the overall energy requirement of the building, as well as its carbon footprint. The fresh, filtered and tempered air is then supplied into the living areas of the home, providing a good level of indoor air quality and preventing humidity which can lead to condensation and mould growth.
Where greater levels of air tightness (of 3m3/h/m2@50Pa or below) are required, MVHR is often specified to secure a larger percentage reduction between the DER (Dwelling Emission Rate) and TER (Target Emission Rate). A high performing MVHR system through SAP (Standard Assessment Procedure) may lower the DER.
For new homes, MVHR is helping to cost effectively contribute towards the improvements in CO2 emissions required by Building Regulations. With MVHR, the incoming air is filtered, improving internal air quality and it also negates the need for window trickle vents. In addition, MVHR is an attractive option for properties requiring acoustic measures as there is no requirement to open windows. For example, for homes located near busy roads or airports.
It is essential that a ventilation system is correctly sized to be able to perform effectively. If the unit is undersized, it can lead to under performance of the unit and noise issues. This is the reason why we work closely with housebuilders from the design stage to ensure that new homes not only meet the requirements for ventilation but also that the products specified are the correct size and performance to meet the application.
Correct installation is also essential with MVHR systems to ensure their effectiveness.
Since 2010, revisions to Building Regulations Part F meant domestic ventilation became notifiable work, requiring ventilation provision to be installed by a competent and qualified person. It is vital that the installation of any domestic ventilation system is correct and meets the minimum requirements set out in regulations and standards. Over 90 per cent of faults with ventilation systems are down to poor installation.
Housebuilders are increasingly requiring their installation teams to be NICEIC trained, which means they can work with the latest types of domestic ventilation products efficiently, receiving technical information and advice, plus practical support. Training via our NICEIC approved centre in Harrogate also ensures that installers are qualified to inspect and test ventilation systems, as well as to commission them effectively.
Latest technological developments are helping with both the commissioning of MVHR systems and with their control. For example, the myenvirovent app designed for our MVHR units gives greater control to the homeowner, plus speeding up commissioning for the installer and making it much simpler and more efficient. It allows them to connect directly to the unit through the app without the need for a wireless internet connection.
The latest generation of MVHR systems are highly efficient and can recover over 90 per cent of the heat that would normally be lost to the outside via trickle vents or extract fans. As this energy is then supplied back into the house as warmed, fresh air, it ensures that developers are able to reduce the overall energy requirement of the building. There are obvious benefits to homeowners who are looking to reduce their energy bills.
Installing MVHR systems has proven to be the most effective way that the new build sector can meet Part F requirements and improve SAP ratings. The trend towards fitting MVHR systems in new homes therefore looks set to continue as part of improving indoor air quality and achieving compliance.