MVHR is widely specified to deliver internal air quality required in increasingly airtight new dwellings, however as John Kelly at Airflow Developments explains, the next step to efficiency is to integrate smart, internet-capable systems.
Pressure for all new buildings to be low energy, plus the requirement for more affordable living developments as well as low-cost eco homes – allied to an increased desire from homeowners to be greener and reduce energy bills – is driving greater insulation and increasingly hermetic sealing of buildings.
Whether a building is earmarked for domestic private housing or social housing, architects will be focused on the need to provide effective ventilation to counteract reduced air infiltration rates. This is because a sealed building is more susceptible to damp, mould and condensation, especially in areas such as kitchens and bathrooms where higher levels of heat and moisture are generated through activities such as cooking and bathing.
Without effective ventilation the building fabric can deteriorate leading to costly and time-consuming repair work. It can also pose potentially serious health problems for homeowners. We spend more than 90 per cent of our time indoors and when you consider the average adult requires 15,000 litres of clean air every day, you begin to see how crucial effective ventilation solutions are to extract stale and polluted air and providing fresh, healthy air to occupants.
Mechanical Ventilation with Heat Recovery (MVHR) is a solution to the problem, continuously preheating the incoming cool supply air using heat from outgoing exhaust air. Heat which would otherwise be expelled is therefore put to use, thanks to a heat exchanger. In some cases, this technology can achieve upwards of 90 per cent thermal efficiency.
It has been estimated that 41 per cent of UK homeowners currently have some form of connected technology installed in their home; by 2020 it is predicted every household will contain an average of 10 connected devices.
This, plus homeowners becoming more energy aware means that smart ventilation systems capable of allowing real-time monitoring and control of indoor air environments via a computer or portable device – at home or on the move – are becoming a wise specification choice.
The integration of smart ventilation can help homeowners reduce energy consumption and maximise indoor air quality. Units designed with different profiles to choose from offer users the ability to program the units according to their personal routines and preferences. Setting ventilation to ‘Away’ during workdays will ensure the unit recognises the decreased levels of CO2 and avoid unnecessary heat recovery and ventilation into the premises – reducing energy costs and wastage.
Some smart MVHR units also have the option to install two external switches. This allows one switch to be set to ‘Boost’ profile within a kitchen or bathroom to accommodate for fluctuating indoor atmospheres, and another can be programmed to alternate between ‘Home’ and ‘Away’ profiles – saving energy simultaneously.
Architects should also expect internet-capable MVHR systems to be designed with an integrated humidity sensor that monitors the humidity level of the dwelling and automatically adjusts the ventilation to an optimal level.
Specifying a unit that incorporates frost protection so the unit does not freeze in the winter, and a 100 per cent effective summer bypass mechanism so that the dwelling does not overheat during the summer, are also essential features. It is advisable to choose a ventilation system that includes a 100 per cent effective bypass mechanism to ensure the MVHR unit reduces solar gain by guaranteeing that the supply air is never warmed unnecessarily by the hot extract air passing through the heat recovery core.
As our buildings become increasingly tightly sealed and properly insulated it is only reasonable to assert that noise from the outside will permeate less. This means the noise output of ventilation systems will become more noticeable to clients. Therefore it is also important to specify ventilation units that incorporate low energy/noise EC fans and a thick insulation casing to significantly decrease noise levels. High-performance ducting can also help reduce noise by up to 29 dB and ensure zero leakage of incoming and outgoing air.
Advice for architects
Those responsible for planning ventilation in any building and wishing to take advantage of the latest energy recovery and interactive technology should always seek advice from reputable manufacturers to help specify the most effective solution. Specialist firms will be able to examine the size and type of the building and look at where an architect is planning to have ventilation installed to suggest how each dwelling can optimise air quality – and which system will ensure the right rate of air extraction per room.
Effective control of the chosen ventilation system is an absolute prerequisite for an energy efficient dwelling. Without controls that are correctly set up (as well as understood and used by end-users) maximum efficiency can never be achieved. Giving homeowners the ease and accessibility to simply register their smart ventilation unit to the Cloud and control air flow settings via a computer, mobile or fixed controller is one route to success. Not only will this mitigate energy wastage and improve air quality – but also help contribute to a better quality of life.
John Kelly is marketing manager at Airflow Developments.