Importance of indoor air quality in energy-efficient homes

By Stephen Glass, Technical Sales Engineer at Nuaire

The report by the Royal College of Physicians, published in February 2016, highlighted to risks posed by poor indoor air quality, and put the NHS at the forefront of the debate on IAQ.

This report, coupled with research from NICE and the World Health Organisation on the sources and effects of indoor air pollutants, gives weight to the arguments put forward by the ventilation industry that IAQ must become a greater focus by the government and within Building Regulations and for the Government.

A further report by Professor Awbi: ‘The Future of Indoor Air Quality in UK Homes and its Impact on Health’, argues that building regulations aren’t taking into account the impact of improved air-tightness and increased energy-efficiency on indoor air quality and people’s health.

Prof. Awbi recommends that 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 protect our health. Continuous mechanical ventilation is, he says, the most effective way of hitting these rates whilst saving energy. So for new build homes, MVHR is the key.

What retrofit ventilation products will help

But what about the millions of existing homes across the UK, especially those in areas of high air pollution? What retrofit ventilation products will help? We see Positive Input Ventilation, a technology invented by Nuaire in the 1970s, as the more effective retrofit solution.

Nuaire’s Solutions For Improving Indoor Air Quality

The ‘Fabric First’ approach to building new homes helps to achieve sustainability, high thermal performance and cost-efficiency without the need for solar technologies. These air-tight construction methods can result in poor indoor air quality as condensation and indoor pollutants remain trapped inside the home.

Adequate ventilation is key to the ‘fabric first’ approach

MVHR is still the most effective ventilation strategy for homes built with high thermal values and high air-tightness. Our range of low-energy systems include models that are designed to fit around the size and use of the new build property. From low-profile systems designed to fit into apartments shallow ceiling voids, up to our largest units for properties with up to six wet rooms. By running continuously, an MVHR system will extract stale air which has been contaminated by indoor pollutants whilst filtering out pollen, pollutants and dust particles from the incoming air, thus ensuring good indoor air quality.

Changes to Building Regulations Part L

Which focus on conservation of fuel and power, have put an even greater focus on cutting carbon usage through improving the fabric energy-efficiency of new build homes. This is good news for the environment and for homeowners who will benefit from the 6% improvement on carbon reduction from the 2010 regulations; however, the regulatory changes don’t include advice on ensuring good indoor air quality. In an age where many homeowners filter their tap water through fear of drinking chemicals, many are unaware of the chemicals and pollutants they breathe in on a daily basis in stale air that is trapped inside the home.

At Nuaire, we are going a step further with the launch of our new Q-Aire Carbon Filter. It is specifically designed for homes in urban areas and it supports the MVHR system by ensuring the air is properly filtered before it enters the property. This measure protects the homeowner from damaging air pollutants such as carbon dioxide and nitrogen dioxide.

The Carbon Filter is suitable for specification and allows contractors to meet planning obligations when building homes and apartments in areas with high air pollution. We’ve designed it to be easy to install but also easy for the homeowner to maintain, because, as we know, effective maintenance is the only way to ensure the MVHR system does its job properly. The filters are built with innovative Colourcell ™ technology, which provides a visual indicator of when the filters need to be changed: a simple change of colour.

What Can Go Wrong If the Wrong System Is Specified?

Planning and installation are the key to an effectively operating MVHR system. Manufacturers like Nuaire offer a great deal of advice and support to consultants at the planning stage, to ensure that the right system is specified. However, a recent trend in apartment building is for MVHR systems to be selected based on the size of the cupboard or wall space, not on the requirements of the apartment.

Added to this, the MVHR systems are then run at top speeds to tackle the common problem of over-heating, problematic in areas of high air or noise pollution where openable windows are ruled out by planning restrictions. A unit that is too small to ventilate the size of property, also run at maximum speeds to tackle over-heating, will no-doubt be noisy.

Nuaire has designed a solution to this problem with its Q-Aire MRXBOX-ECO-1Z, a unique all-in-one acoustic enclosure that removes breakout noise and vibration. This solution allows contractors to meet the strict noise requirements set out by CIBSE guidelines.

Importance of indoor air quality in energy-efficient homes

Positive Input Ventilation

Drimaster-Eco range as well as being able to provide more traditional mechanical ventilation solutions, Nuaire is able to offer an alternative and equally robust approach when heat recovery is not required.

Our alternative approach is a strategy called is Positive Input Ventilation (PIV) which was invented by Nuaire back in the 1970s. It’s now installed in over 1 million UK homes as a low-energy, low cost solution to combat condensation and indoor pollutants, and it’s suitability to new build ventilation is now being recognised.

Importance of indoor air quality in energy-efficient homes

This strategy works by providing a continuous supply of fresh, filtered air into the house through a fan mounted in the loft. The gently warmed input air enters the home through a ceiling diffuser, creating a positive pressure effect that reduces humidity levels and forces out air pollutants, improving indoor air quality and helping to minimise the entry of harmful Radon gas.

Positive Input Ventilation (PIV) will work without the need for any trickle ventilators down to an air permeability of 3m3h/m2 ensuring an additional saving for the homeowner. The Drimaster-Eco range includes three models. A unique feature is the sleek, circular ceiling diffuser which houses the system controls, allowing adjustments and commissioning to be carried out from the hallway without having to enter the loft.

Added controllability comes from the remote sensors and controls that instruct the PIV system to respond accordingly to changing humidity and CO2 levels. This controllability improves indoor air quality and helps save energy. Nuaire is excited to be the first manufacturer to full demand-control through these energy-saving controls and sensors. This development marks an exciting change of direction for PIV.

Unlike other PIV systems on the market, the Drimaster-Eco range offers twice as much filter area so the filters are more effective for longer. Small and light, the new unit offers an extended duct length to overcome installation restrictions, and can be hung at the right height to maximise heat gains within the loft space. The DRI-ECO-HEAT features an integral heater which is sited uniquely between the flexible duct and the diffuser. The unique heater position offers the same performance whilst using up to 20% less energy than the competition. This means lower running and life cycle costs.

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