Government incentives designed to encourage energy efficiency, coupled with technological advancements, have applied pressure on the construction industry to build increasingly airtight buildings of late. However, high levels of airtightness and poor ventilation are building up major health problems in new housing, according to a study by Glasgow School of Art’s Mackintosh Environmental Architecture Research Unit (Mearu). Building Specifier’s Joe Bradbury investigates:

Researchers at Mearu have uncovered serious indoor air quality (IAQ) problems in a wide range of new homes that had been built to be airtight and, as a result, were increasing instances of asthma and other respiratory problems in occupants.

Mearu studied 200 modern homes and found widespread evidence of poor ventilation, with bedrooms being a particular problem. The unit has produced a public awareness film urging people to ventilate their homes properly by “keeping vents or windows open when cooking, showering and cleaning; drying laundry near an open window; and opening windows at night.”

Head of Mearu Professor Tim Sharpe said “Poor indoor air quality is hard for people to detect. There are clear links between poor ventilation and ill health, so people need to be aware of the build-up of CO2 and other pollutants in their homes, and their potential impact on health.

“Modern homes are increasingly airtight and can also contain a great number of pollutants and chemicals, many of which can have serious health effects.”

Airtightness in a post-COVID world

Covid-19 has shone a spotlight on the devastating consequences of having respiratory issues. Seeing people gasp for air in hospital beds on respirators is hardly an image we are likely to forget in a hurry. However, it isn’t just coronavirus that attacks the lungs. Poor indoor air quality is linked to cancer, lung disease, COPD and asthma amongst other potentially fatal conditions.

On average, 3 people a day die from asthma alone. There are 5.4 million people (1.1 million children and 4.3 million adults) in Great Britain known to be suffering from the condition… and they are just the ones that came forward for treatment. An untold number battle through their symptoms undiagnosed. The UK has some of the highest asthma rates in Europe. Every day, the lives of three families are devastated by the death of a loved one to an asthma attack, and tragically two thirds of these deaths are preventable.

Indoor air quality is essential in the treatment and prevention of Asthma, along with many other respiratory conditions.

If you are building a new domestic property or commercial property of a certain size, it will need to undergo air tightness testing. This assesses the building for ‘air permeability’, checking for air leakage through gaps, holes and other areas. The Government has SAP (Standard Assessment Procedures) in place for air tightness testing, setting standards buildings must comply with to be energy efficient.

Airtightness in buildings has improved to such a degree in recent years and ventilation has had to play catch up. Adequate ventilation in airtight buildings is essential and mechanical ventilation with heat recovery (MVHR) systems offer that effective, efficient and clean way of ventilation so sorely needed by people living in poor quality air across Britain today.

Ventilation is the answer

MVHR (Mechanical Ventilation with Heat Recovery) provides fresh filtered air into a building whilst retaining most of the energy that has already been used in heating the building. Heat Recovery Ventilation is the solution to the ventilation needs of energy efficient buildings. Mechanical ventilation with heat recovery (MVHR), heat recovery ventilation (HRV) or Comfort ventilation are all names for the same thing. A heat recovery ventilation system properly fitted into a house provides a constant supply of fresh filtered air, maintaining the air quality whilst being practically imperceptible.

MVHR works by extracting the air from the polluted sources e.g. kitchen, bathroom, toilets and utility rooms and supplying air to the ‘living’ rooms e.g. bedrooms, living rooms, studies etc. The extracted air is taken through a central heat exchanger and the heat recovered into the supply air. This works both ways, if the air inside the building is colder than the outside air then the building will retain its nice and cool temperature.

In a recent article featured on renewables experts Mitsubishi’s news site ‘The Hub’, Paul McLaughlin, chief executive of the Building Engineering Services Association (BESA) said “a well-sealed building envelope combined with effective filtration of incoming supply air can reduce particle penetration by 78%. Considerable investment has already been made in improving the airtightness of buildings to reduce energy consumption and that same process can be used to manage air quality.”

“The general public already understands the impact temperature has on healthy and productive conditions inside buildings — we now need to stress that the same principle should apply to air quality.

“When it is too hot or cold outside, people now expect to be able to enjoy comfortable temperatures inside. They should also expect similar protection from rising air pollution.”

As an industry, we are responsible for the comfort and wellbeing of the occupants of the buildings we make and maintain. It’s also our duty to ensure we are taking adequate steps towards renewables. Especially these days! MVHR can tick both of these boxes, so it’s time to sit up and take note.

Bringing the fresh air indoors

When we are inside the home, an indoor workplace (or any other type of building, for that matter), we are placing ourselves unwittingly at the mercy of the air within that building. Any chemicals, toxins or pollutants are drawn into our bodies and can cause headaches, eye irritation, skin problems, allergies and fatigue. Prolonged exposure to more serious pollutants can even cause certain types of cancers and other long-term health complications. As specifiers building structures designed for people, we have to consider this in our projects and ensure we do everything within our power to protect occupants from the invisible menace of unclean air.

MVHR (Mechanical Ventilation with Heat Recovery) provides fresh filtered air into a building whilst retaining most of the energy that has already been used in heating the building. Innovations within the field of airtightness in buildings have happened so rapidly in recent years and ventilation and heat recovery have had to play catch up to keep up with the momentum. Adequate ventilation in airtight buildings is essential and mechanical ventilation with heat recovery (MVHR) systems offer that effective, efficient and clean way of ventilation so sorely needed by people living in poor quality air across Britain today.

In summary

The general public understands the impact temperature has on healthy and productive conditions inside buildings sadly all too well; fuel poverty and winter deaths take centre stage in our newspapers and magazines. Unfortunately, the fact that air quality is equally as impactful on society is regularly overlooked, especially in 2021 when the news is dominated with COVID, Brexit and not much else…

Regardless of how hot or cold it may be outside, people have come to expect comfortable indoor temperatures. They demand that from their buildings. They now need to invoke the same demand for protection from harmful air pollution. Get either wrong and you run the risk of harming your occupants.

Warmth and clean air to breathe is essential. As an industry, we are responsible for the comfort and wellbeing of the occupants of the built environment. We must also ensure we are moving forward towards renewables, otherwise I would argue that we aren’t moving forward at all. MVHR just might be the answer.

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