Ian Mitchell, Product Marketing Manager – New Build Residential at Vent-Axia, explained how the market is developing and what housebuilders need to consider when specifying MVHR.
Housebuilders are looking for a ventilation solution that saves energy, reduces carbon emissions and provides good indoor air quality (IAQ). With Mechanical Ventilation with Heat Recovery (MVHR) ticking all the right boxes it is no surprise that the industry volume is 50,000 units a year and still growing – with it set to dominate ventilation in most new homes post-2016.
Energy efficiency
For housebuilders energy efficiency is still the most important specification factor when it comes to ventilation as they seek the most cost-effective way to achieve carbon reductions and reduce dwelling emission rates (DER). The 2014 amendments to Part L of the Building Regulations introduced the FEES (Fabric Energy Efficiency Standards) which focuses on the efficiency of the fabric of the building in new homes.
As a result of this fabric first agenda there has been a move from intermittent to continuous ventilation since it is important to ventilate effectively and efficiently in airtight thermally efficient homes. This is further driving the adoption of continuous centralised MVHR systems as well as driving design innovation as manufacturers strive to develop ever more efficient units.
Specifying an MVHR unit which boasts low energy usage and high thermal efficiency is key to reducing a home’s DER. However, this move towards more airtight, better insulated dwellings also means a greater focus on the installed performance of ventilation.
Competent Person
To ensure optimum installed performance it is key an MVHR system is fitted by a ‘Competent Person’ that has undergone training. For housebuilders this has two benefits, as well as helping to ensure installed performance, using a Competent Person to install an MVHR offers a benefit in PCBD by rewarding housebuilders with a lower DER.
The NICEIC now offers a new competency qualification for installers of Domestic Ventilation Systems. Once installers hold the qualification then they can apply to NICEIC Competent Persons Scheme for Ventilation so they can self-certify their work in England & Wales.
Noise reduction
However, it is not only energy efficiency which is driving developments in housebuilding ventilation. Interestingly the latest product design influences are coming directly from consumers, such as silent ventilation. With increasingly busy, stressful lives silence is now a valued commodity and comfort issue for consumers and so an attractive specification feature for housebuilders. This is driving innovation in developing quiet ventilation solutions.
Air quality
Another area consumers are becoming aware of is indoor air quality (IAQ), which follows a raft of research. Most recently the high profile report, ‘Every breath we take: the lifelong impact of air pollution’ from the Royal College of Physicians starkly set out the dangerous impact air pollution is currently having on our health.
As consumers have become more informed of the health implications of IAQ MVHR is coming to the fore as the ventilation solution of choice. ‘The Future of Indoor Air Quality in UK Homes and its Impact on Health’, a recent report by Professor Hazim Awbi, at The University of Reading, states the health risks associated with poorly ventilated homes in no uncertain terms.
The research suggests there should be a legal requirement for new homes, and guidance for retrofitted homes, to have an air exchange rate of at least 0.5/hour, to help protect human health. It also advises that the most cost-effective solution for achieving this exchange rate, whilst still satisfying energy efficiency requirements, is the standardised fitting of effective continuous mechanical ventilation, preferably with heat recovery (MVHR).
An additional benefit of MVHR systems when it comes to IAQ, is that they provide filtration of the outside air before it enters the building. This contrasts with traditional ventilation systems where replacement air is drawn directly from outside without filtration, this means any external pollution is brought straight into the building and into the air households breathe.
Maintenance
As New Build homes become more air tight and IAQ increases in importance, maintenance of MVHR systems is also coming to the fore. It is not only important to specify an MVHR unit that can provide good IAQ, it is also vital to ensure this continues by maintaining the system and changing filters.
To help address this, in January 2016 European legislation (ERP) came into force which requires MVHR producers to meet minimum technology requirements. These include an indication of the ventilation unit status (e.g. fault condition) visible to the home owner so that they know if their MVHR system is operating correctly. (This has been available from Vent-Axia since 2008.)
Meanwhile, the NHBC has also issued guidance to housebuilders, which recommends ventilation units are placed in an accessible position in a home rather than a loft where it may be difficult to maintain.
Design solutions
The latest MVHR units address all these market drivers, such as Vent-Axia’s Sentinel Kinetic Advance. Designed for the new build residential market, the Advance fulfils housebuilders’ desire for efficiency, topping the PCBD list as the best performing MVHR unit in its class, offering valuable reductions in DER.
However, the Advance also achieves the holy grail of high efficiency and low sound levels with trickle settings of up to 40% that still stay below 20dBA. It boasts a specific power (SFP) as low as 0.38W/l/s, combined with 93% heat recovery and an airflow of 100l/s at 150Pa.
So as MVHR continues to increase its penetration the market is maturing, raising the bar on specification. Housebuilders are therefore increasingly asking for greater levels of control and more innovative product features. Controls and connectivity are set to be the next key trends in MVHR as well as a clear focus on reducing sound levels for the end-user as we move towards the technology dominating new build residential ventilation.
